# SPEAKER WIRING



## Guv'nor

The most common methods to wire up speakers are Series and Parallel.

It is also quite common to wire Speakers in a Series/Parallel Combination.





Single speaker

Wiring up Speakers correctly to provide the best possible sound, requires some knowledge of Loading, Phase, and Impedance, while understanding Ohms Law will help you to connect your speakers properly.

*SERIES*






Adding Speakers in series increases the overall resistance of the circuit. 

Therefore the resistance of each Speaker is added together, For advanced installations with Multiple Speakers, Series Speaker wiring can be used to increase the resistance of the “equivalent” or “overall” resistance that the Amplifier sees. This allows the Amplifier to run cooler and more efficiently. 

Series Circuits are “voltage dividers”, and using Ohms Law, one sees the result as a decrease in amplified voltage audio signal to each Speaker. Since Series Circuits are “voltage dividers” each Speaker sees a percentage of the amplified output from the Amplifier. It is often assumed the Amplifier is producing less output, but it still produces the same output, because each Speaker only gets a percentage of the overall power. 

Formula: Znet = Z1 + Z2 + Z3 + .... + Zn

_Example:_

2 x 4 Ohm Speaker = 4 + 4 = 8 Ohm Load
2 x 8 Ohm Speaker = 8 + 8 = 16 Ohm Load

*PARALLEL*






Adding Speakers in parallel decreases the overall resistance of the circuit 

Parallel Speaker Wiring combines all Speakers (+) positive Speaker leads together, and all (-) negative Speaker leads together. 

Adding additional Speakers is as easy, however, adding Speakers in Parallel causes the overall resistance of the circuit to drop, as resistance drops, the current must increase according to Ohms Law. So, each time a Speaker with the same resistance is added to the parallel circuit, the current draw on the amp increases. The circuitry of the amp must be able to handle this increase in current at the reduced resistance. 

Formula: Znet = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)

_Example:_

2 X 4 Ohm Speaker = 1 / (1/4 + 1/4 ) = 2 Ohm Load
2 x 8 Ohm Speaker = 1 / (1/8 + 1/8 ) = 4 Ohm Load
_
Note:_ If more than 2 Speakers are connected in Parallel, so long as they are all the same impedance then the net impedance of the load is equal to the impedance of the one Speaker divided by the total number of Speakers. For Example 3 8 Ohm Speakers in Parallel, the Impedance is 8/3 or 2.667 Ohms.

*A COMBINATION OF SERIES & PARALLEL*






In reality this is just two sets of Series Speakers wired in Parallel 

Formula: Znet = Znet1 + Znet2 + ... + Znetn; where Zneti = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)

_Example:_

4 X 8 Ohm Speaker = [1 / (1/8 + 1/8 )] + [1 / (1/8 + 1/8 )] = 4 + 4 = 8 Ohm Load

*WIRING A FULL STACK*

The amp usually has two speaker outputs (one for each cab)

The output jacks are wired in parallel. It means Znet = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)

Therefore having 2 cabs at 8Ohm the head will see 1 / (1/8 + 1/8 ) = 4 Ohm Load

Enjoy!


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## superleadfixer

Also the serie/parallel combination in a 4x12 cab will have a draker sound and a little harcher, if your amp (set up) is too dark one way to help this out would do a Parallel/series connection instead, that will give a little bit cleaner and brighter sound.........


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## surfdog777

Correct me if this is wrong, I'm running both cabs in a full stack 16ohm mono, the head is set at 8 ohms....this is the correct setting, eh?


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## Guv'nor

1 / (1/16 + 1/16 ) = 1 / (0.0625 + 0.0625) = 1/0.125 = 8 Ohm Load 

You're ok.


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## Jimib

I am looking at buying a cab that has 2 16ohm speakers in it, am i correct in saying my amp should be set at 8 ohms?

Thanks


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## Pearse

I have a 1960A cab and looks like the speakers were refitted. there are 4 15 ohm speakers its not wired the same way as celestion would have said to wire it in their series diagram, its simpler like one speaker connected to another speaker and the two end wires are conected to the terminals. What do i choose, or do. It still works fine on the 16 omh output.


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## KingKong

Howdi all,

I just signed up on the forums and am in need of assistance!

I just bought a nearly new tsl 100 head, and I want to make sure my cabinet is wired for 16 ohm impedance. I'm attaching a pic. The lower terminal of the upper right speaker (as you look at the pic) is positive. I believe the top speaker terminals on the speakers on the left are positive (marked with red dot). The speakers are each 16 ohm. I believe the top two are wired together in series, the bottom two are wired together in series, and the upper pair is wired to the lower pair in parallel.

If anyone could take a look at this and share an opinion I'd appreciate it!

I'm thinking it's 16 ohms total impedance, but I'd like another opinion before I use the 16 ohm output from the tsl 100.

Thanks!
Kong


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## Adwex

KingKong said:


> Howdi all,
> 
> I just signed up on the forums and am in need of assistance!
> 
> I just bought a nearly new tsl 100 head, and I want to make sure my cabinet is wired for 16 ohm impedance. I'm attaching a pic. The lower terminal of the upper right speaker (as you look at the pic) is positive. I believe the top speaker terminals on the speakers on the left are positive (marked with red dot). The speakers are each 16 ohm. I believe the top two are wired together in series, the bottom two are wired together in series, and the upper pair is wired to the lower pair in parallel.
> 
> If anyone could take a look at this and share an opinion I'd appreciate it!
> 
> I'm thinking it's 16 ohms total impedance, but I'd like another opinion before I use the 16 ohm output from the tsl 100.
> 
> 
> Thanks!
> Kong




Welcome, Kong.

It's tough to see in the pic exactly how the bottom pair is wired, but the way you describe everything is correct: top pair in series + to -, bottom pair in series + to -, with the two pairs wired together in parallel + to +, and - to -. Wired this way, if all the speakers are the same impedance individually, the total impedance of the 4 will be the same as the impedance of one, so use the 16 ohm output on the TSL.

Interesting mix of speakers. I recognize the V30, but what are the others?

Can you take a better pic detailing the wiring on the bottom pair? ...and exactly which terminals are used to connect the top and bottom pairs in parallel?

Adam


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## KingKong

Adwex said:


> Welcome, Kong.
> 
> It's tough to see in the pic exactly how the bottom pair is wired, but the way you describe everything is correct: top pair in series + to -, bottom pair in series + to -, with the two pairs wired together in parallel + to +, and - to -. Wired this way, if all the speakers are the same impedance individually, the total impedance of the 4 will be the same as the impedance of one, so use the 16 ohm output on the TSL.
> 
> Interesting mix of speakers. I recognize the V30, but what are the others?
> 
> Can you take a better pic detailing the wiring on the bottom pair? ...and exactly which terminals are used to connect the top and bottom pairs in parallel?
> 
> Adam



Thanks for the response and the welcome Adam.

I bought this cabinet in about 1990, used and battered. One of the speakers was blown, and I replaced it with the V30. After a phone call to Marshall and some checking on the internet I dated the cabinet to the late 70's and was told it was a bass cabinet. 

It's pretty late here and I'm headed to bed, but tomorrow I'll open it up again and post some more detailed pictures of the wiring and speakers.

Thanks again!

-Kong


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## KingKong

Adwex said:


> Welcome, Kong.
> 
> It's tough to see in the pic exactly how the bottom pair is wired, but the way you describe everything is correct: top pair in series + to -, bottom pair in series + to -, with the two pairs wired together in parallel + to +, and - to -. Wired this way, if all the speakers are the same impedance individually, the total impedance of the 4 will be the same as the impedance of one, so use the 16 ohm output on the TSL.
> 
> Interesting mix of speakers. I recognize the V30, but what are the others?
> 
> Can you take a better pic detailing the wiring on the bottom pair? ...and exactly which terminals are used to connect the top and bottom pairs in parallel?
> 
> Adam



OK, I took some more pics and here they are...

The lower 2 are original G12H 30 Watts. Above are a G12C-30 and a G12 Vintage 30.

I have no idea where these speakers rank in quality, I just know the thing sounds great. I'd love to hear anyone's assessment of this setup and if there's any reason these speakers should not be mixed!


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## Adwex

KingKong said:


> OK, I took some more pics and here they are...
> 
> The lower 2 are original G12H 30 Watts. Above are a G12C-30 and a G12 Vintage 30.
> 
> I have no idea where these speakers rank in quality, I just know the thing sounds great. I'd love to hear anyone's assessment of this setup and if there's any reason these speakers should not be mixed!



Well the wiring looks correct. As far as ranking, I'd say those G12H's on the bottom rank pretty high on the quality scale. I have one new G12H Heritage, and it's a killer speaker (expensive too). The V30 is a V30...good, but not quite a G12H. I know nothing about the G12C, but from the looks of the small magnet, I'd guess that it's the weak link in your chain. I don't know, maybe it adds something the others don't have.

Good heavy gauge speaker wire too.

Post a sound clip if you can.


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## kharvelan

since none of the images are showing, I was digging around to find a site that had good diagrams of both series and parallel wiring in both 2x12 and 4x12 configurations.

I found this site which I think spells it out very easily exactly how to wire:

Wiring a 4 X 12 Speaker cabinet

Wiring a 2 X 12 Speaker cabinet

hope that helps!


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## ironmaidencanada

does anyone know how to hook up 4 cabs(8ohms each) to one amp head, all the cabs have outs and i have 4 8 and 16 ohm outputs on the head,any help would be greatly appreciated!!thanks


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## Pturpin1

Need Help wiring my DSL 100 to 1 4x12 and 2 4x10 cabinets. Any help would be greatly appreciated.

Thanks


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## Adwex

Pturpin1 said:


> Need Help wiring my DSL 100 to 1 4x12 and 2 4x10 cabinets. Any help would be greatly appreciated.
> 
> Thanks



Are the cabs both the same impedance?


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## Pturpin1

Yes They're both 8 ohms.

Thanks


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## Adwex

Then it's simple...connect the cabs to the speaker jacks labelled something like "4 or 8 ohms only", and make sure the switch is set for 4 ohms.

Since you are connecting 2 cabs, 8 ohms each, and the speaker jacks on the back of the amp are wired in parallel, the resultant impedance will be 1/2 the impedance of just one cab alone. That's why 2 cabs, at 8 ohms each will be the same as 1 cab at 4 ohms.


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## Pturpin1

Thanks
So the DSL should be set on 4 ohm.
One Line should go to the 4x12 switched to 4 ohm.
I now have two 4x10 8 ohm cabs. left to hook up.
Should I use a Y Connector?


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## Adwex

Pturpin1 said:


> Thanks
> So the DSL should be set on 4 ohm.
> One Line should go to the 4x12 switched to 4 ohm.
> I now have two 4x10 8 ohm cabs. left to hook up.
> Should I use a Y Connector?



Huh??!!

NO !!!

Wait, I'm sorry, I mis-read your original post, I didn't know you had 2 4x10 cabs.

You cannot use all 3 cabs, you can only use 2 of them.


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## Pturpin1

Bummer
thanks for the info.


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## Pturpin1

Just Curious.

What would happen if I did use a y connector?

Is there no way of wiring the 2 4x10 cabs (8ohm) to essentially be 1 8x10 cab 4(ohm)?

Thanks


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## Adwex

Pturpin1 said:


> Just Curious.
> 
> What would happen if I did use a y connector?
> 
> Is there no way of wiring the 2 4x10 cabs (8ohm) to essentially be 1 8x10 cab 4(ohm)?
> 
> Thanks



Yes, you can...2 4x10 cabs wired in parallel will equal 4 ohms, but if you combine that with the 8 ohm 4x12 cab, the resulting impedance will be 2.66 ohms. I don't think your amp has a setting for that.


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## Pturpin1

Thanks Again


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## arantes71

Hello there, I have a strange (at least in my opinion) case with a 412 cabinet that a friend actually gave to me together with his JMP head because he doesnt have the energy to bother with garbage that doesnt work... His loss I suppose.

Anyway, the cabinet is a 8412 with 4 8 ohm Celestion G12L speakers, and for some reason just two of them work. 

I tried the 9v battry check, and they all popped, and I followed the link above to that helpful site with wiring for dummies like me, and as far as I can see the cab is set up in series/parallell combination. The wires look completely ok as far as I can see, but just the same, the upper two speakers are dead. 

I should mention too that the input socket has suffered some beating and is fixed with some of that ole duck tape.

Anyone got a clue?


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## Adwex

First thing I would do is take off the duct tape and see what's going on with the connections. Obviously the top 2 speakers aren't connected properly.


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## arantes71

Thank you for the reply!

I did take the duct tape off, and it looks the way it should - the damage is just the plastic, not the wiring. But I have a theory about how the two speakers closest to the input is not working while the others do - I believe it has to be the first minus-plus connector between the two speakers that is broke somewhere - gonna try bypassing it...


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## arantes71

Must have been cheating with the 9 volt battery yesterday - one speaker is actually dead... Wonder how expensive a G12L is these days, and where to find one...


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## Adwex

arantes71 said:


> ... Wonder how expensive a G12L is these days, and where to find one...



G12L = V30

Buy Celestion Vintage 30 Speaker online at Musician's Friend


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## rmrunner

can some one help me....i am running two cabinets. each cabinet has a 8 ohm horn(has condenser) and a 500W 4ohm 10''. should i run this in series arrangement or parallel arrangement? amp impedance is 6-16 ohms


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## cadaver_occulta

Adwex said:


> Yes, you can...2 4x10 cabs wired in parallel will equal 4 ohms, but if you combine that with the 8 ohm 4x12 cab, the resulting impedance will be 2.66 ohms. I don't think your amp has a setting for that.



Out of curiosity, if 1 8x10 (or 8x12 i hope) cabinet equals to 4 ohms, then would there be any problem running 2 8x10 (12) cabs from 1 head if the amp has two speaker outputs?


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## Adwex

cadaver_occulta said:


> Out of curiosity, if 1 8x10 (or 8x12 i hope) cabinet equals to 4 ohms, then would there be any problem running 2 8x10 (12) cabs from 1 head if the amp has two speaker outputs?



Yes, there is a problem. 2 8x10 cabs, at 4 ohms each, will equal 2 ohms when you them both into the amp. I don't know of any amp that can run at 2 ohms.

You could wire the two cabs in series with each other, then they would combine to equal 8 ohms.


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## tim warner

I was going to ask in another thread but you guys are already started.
I have 2 g12m 16 ohm speakers that I want to hook these up to my 100 watt superlead,
I know I won't be able to (give'er all she's got), but what is the best way to wire these?


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## Adwex

tim warner said:


> I was going to ask in another thread but you guys are already started.
> I have 2 g12m 16 ohm speakers that I want to hook these up to my 100 watt superlead,
> I know I won't be able to (give'er all she's got), but what is the best way to wire these?



There is only one way to wire them, in parallel. The result will be 8 ohms.
The max power handling of this combination will be 50 watts. Your 100 watt superlead is quite capable of blowing the speakers if you crank it.


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## Jimib

cadaver_occulta said:


> Out of curiosity, if 1 8x10 (or 8x12 i hope) cabinet equals to 4 ohms, then would there be any problem running 2 8x10 (12) cabs from 1 head if the amp has two speaker outputs?



If your amp can go to 2ohms then it's not a problem but running two 4ohm cabs on 4ohms could get nasty so no lol ....


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## cadaver_occulta

Adwex said:


> Yes, there is a problem. 2 8x10 cabs, at 4 ohms each, will equal 2 ohms when you them both into the amp. I don't know of any amp that can run at 2 ohms.
> 
> You could wire the two cabs in series with each other, then they would combine to equal 8 ohms.




So 2 8x10 (or 12) cabinets could not be plugged in the same way that 2 4x10 (or 12) cabinets could but plugged in to make a full stack...is that correct? Even if each individual speaker is 16ohms each (which would come out 4ohms?) it shouldn't be done? 

Btw, please correct me of any incorrect information, I REALLY dont wanna fry any equipment that I can't afford to replace!!!


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## Jimib

A question myself...
Would it be possible to run a 16ohm cab and an 8ohm cab at 4 ohms? thanks


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## Adwex

cadaver_occulta said:


> So 2 8x10 (or 12) cabinets could not be plugged in the same way that 2 4x10 (or 12) cabinets could but plugged in to make a full stack...is that correct? Even if each individual speaker is 16ohms each (which would come out 4ohms?) it shouldn't be done?
> 
> Btw, please correct me of any incorrect information, I REALLY dont wanna fry any equipment that I can't afford to replace!!!



If the 8x10 cabs are 4 ohms each (the total is what's important, not the individual speakers), then when you connect 2 of them to your amp, the total your amp "sees" is 2 ohms.

If your amp does not have a 2 ohm setting (and I don't think it does), do not connect the 2 8x10 cabs.


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## Adwex

Jimib said:


> A question myself...
> Would it be possible to run a 16ohm cab and an 8ohm cab at 4 ohms? thanks



No.

A 16 ohm cab and an 8 ohm cab when connected in parallel will equal 5.33 ohms.
I can show the math if you want.


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## Jimib

right... I thought that it would be ok then at 5.33 considering its not below 4? please excuse my ignorance lol


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## Jimib

Jimib said:


> right... I thought that it would be ok then at 5.33 considering its not below 4? please excuse my ignorance lol



Am I incorrect in saying that?


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## Adwex

Jimib said:


> right... I thought that it would be ok then at 5.33 considering its not below 4? please excuse my ignorance lol



You MIGHT be ok, but you'll be taking a risk.

You should always match impedance.


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## Radiokt3k

I have:
1 jcm2000 head with 4,8, and 16 selectable switch.
1 1960A 4x12 cab with 4 G12T-75 Celestions wired in Parallel

Can I come out of the 16ohm mono jack from the head with switch
set to 4 ohms to the cabinet?

Thanks,
John


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## Purgasound

NO.

If you only have one cabinet, it's
16 amp out to 16 cab in
or
8 amp out to 8 cab in
or
4 amp out to 4 cab in

The back of the 1960 cab is clearly marked on the right input, MONO 16ohms. Have the switch set to MONO also. Mismatching the impedance will severely damage your amp.
Even safely running the amplifier at 4ohms from the amp to 4ohms on the cab runs your amp harder and stresses it out for no reason. There is no auditory benefits for running low impedance. Stay at 16ohms and keep your amp happy.


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## Adwex

American Viking said:


> NO.
> 
> If you only have one cabinet, it's
> 16 amp out to 16 cab in
> or
> 8 amp out to 8 cab in
> or
> 4 amp out to 4 cab in
> 
> The back of the 1960 cab is clearly marked on the right input, MONO 16ohms. Have the switch set to MONO also. Mismatching the impedance will severely damage your amp.
> Even safely running the amplifier at 4ohms from the amp to 4ohms on the cab runs your amp harder and stresses it out for no reason. There is no auditory benefits for running low impedance. Stay at 16ohms and keep your amp happy.



American Viking speaks the truth...words to live by.

Always match impedance.

Always.


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## wizard_37

I have a quick question, I am fixing to rewire my cab because the wiring is pretty old and I would like to upgrade it, I was thinking about using thicker wire because the exsisting wire is pretty small, which wire would be the best to use?


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## Adwex

wizard_37 said:


> I have a quick question, I am fixing to rewire my cab because the wiring is pretty old and I would like to upgrade it, I was thinking about using thicker wire because the exsisting wire is pretty small, which wire would be the best to use?



I used standard speaker wire I got at Radio Shack (or any electronic store).
I think I chose 14 or 12 gauge, I don't remember. 16 would be ok, but like you, I wanted to upgrade. Btw, in case you didn't know, the lower the gauge number, the thicker the wire.


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## grobinson

so i thought id attach something ive been working on.
16ohm mono / 4ohm mono switching using jacks only and no DPDT switch.

you could use a similar setup (just one switcing jack) to copy the stereo 2x12 input jack plate and just add 2 more 16ohm speakers in parallel to the original two (in two pairs) to get 4ohm mono and 8ohm stereo.


anyway. my diagram.
if someone can take a look at check my wiring and maths is right, i would be happy.
i just boshed this up in photoshop. the green lines mark 'live' signal routes when the jack is put into a socket. the lower switches are all Tip, the upper switches are Sleeve


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## funkplayer

Greetings and salutations from one of your newest members -

I have a Marshall AVT150H w/1960A (300W)- We pratice in a small space and the sound from the cabinet just blows by me at like knee level. I would like to connect a EV-Force I 8ohm 15" spkr with ti horn as a monitor in front of me. The 1960A cabinet is currently plugged into the 8/4ohm jack from the AVT150H. There is another 8ohm jack on the AVT150H. Can I use this jack to run the EV monitor as well as leaving the 1960A plugged into the 8/4ohm jack?


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## Mr69bungle

Please help I am trying to convert my 8 ohm MONO cab to a Stereo cab!
I've checked here- Wiring a 4 X 12 Speaker cabinet for a diagram but as this is my first wiring experience and as i don't want to botch it up I thought I'd ask you're advice. 

The mono setup is shown in the attached pic which is wired up red wire to A1 and black wire to B1 which from my thinking is Speakers in Series-Parallel?

So I'm just not sure where to connect the mono and stereo wires to get a 4 Speaker Switchable Stereo/Mono setup.

I'm thinking that maybe i have to connect the stereo wires to red C1 and black D1??? is that right or do i have to do something different???

Please help - thanks in advance P


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## Adwex

Mr69bungle said:


> Please help I am trying to convert my 8 ohm MONO cab to a Stereo cab!
> I've checked here- Wiring a 4 X 12 Speaker cabinet for a diagram but as this is my first wiring experience and as i don't want to botch it up I thought I'd ask you're advice.
> 
> The mono setup is shown in the attached pic which is wired up red wire to A1 and black wire to B1 which from my thinking is Speakers in Series-Parallel?
> 
> So I'm just not sure where to connect the mono and stereo wires to get a 4 Speaker Switchable Stereo/Mono setup.
> 
> I'm thinking that maybe i have to connect the stereo wires to red C1 and black D1??? is that right or do i have to do something different???
> 
> Please help - thanks in advance Porl




First thing you need to realize is that the ohm values written on the jackplate will be wrong, it is intended to be used with 16 ohm speakers, not 8. It will work electrically, but the cab will not be 4/16 ohms mono or 8 ohms stereo, it will be 2/8 ohms mono or 4 ohms stereo.

In order for the system to work correctly, each half of the cab needs to be wired in parallel. When the switch is set for mono, the internal circuitry in the jackplate connects both sides in series. When set for stereo, both sides are separated from each other.

That's the theory of how it works, I could look closer and help with the actual connections if you want.


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## Mr69bungle

Thank you for your reply. 

Yes i appreciate that the Ohms printed on the back plate would be different.

Oh right i didn't realise it would be 4 Ohms stereo - is there anyway to wire it up as 16 Ohms stereo? 2 x 8 ohm speakers = 16 ohms?

If you could specify which connectors need to go where ie. A1, B2 etc that would be awesome 

Thanks again for you help

Bigger connection picture to follow


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## Mr69bungle

Photo attached of existing wiring and terminals marked up A1-4 etc.

Thanks in advance
P


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## Adwex

Mr69bungle said:


> Thank you for your reply.
> 
> Yes i appreciate that the Ohms printed on the back plate would be different.
> 
> Oh right i didn't realise it would be 4 Ohms stereo - is there anyway to wire it up as 16 Ohms stereo? 2 x 8 ohm speakers = 16 ohms?
> 
> If you could specify which connectors need to go where ie. A1, B2 etc that would be awesome
> 
> Thanks again for you help
> 
> Bigger connection picture to follow



In order to have it wired for 16 ohms stereo, you would have to wire each half of the cab in series. As I said before, the switch on the jackplate when in mono connects both sides in series, so then you would have 32 ohms mono, with all 4 speakers wired in series.

The whole problem with all this is that you have 8 ohm speakers, not 16's. It'll work, but it's unusual, so the markings on the jackplate will be wrong, and you won't be able to use the cab in mono by itself.


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## Adwex

Mr69bungle said:


> Photo attached of existing wiring and terminals marked up A1-4 etc.
> 
> Thanks in advance
> Porl



Just for clarity, could you also indicate the + and - terminals on the speakers.


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## Mr69bungle

Oh i didn't realise that the 8 ohm speakers would be a problem - is there any way around it? Different wiring? 

I wanted to use it with two separate signals going to a 16 ohm (or 8 ohm) 2 speaker configuration on 1 side and another 16 ohm (or 8ohm) 2 speaker configuration on the other side.

I originally saw it here - Wiring a 4 X 12 Speaker cabinet

in the Cabinet Wiring Options sections about half way down
it said this:-

Mono/Stereo in same cabinet
4 Musical Intrument Speakers. Mono/Stereo selectable by using a Switch. 

Option 1
4 - 4 ohm speakers = 8 ohms to each channel if run in Stereo, 4 ohms in Mono mode. 

Option 2
4 - 8 ohm speakers = 16 ohms to each channel if run in Stereo, 8 ohms in Mono mode.

is that right or are they wrong?? 

Thanks again


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## Mr69bungle

I've checked the Polarities and marked them up - hope this helps.

Thanks
Porl


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## Mr69bungle

Is it possible to do the wiring as the attached diagram suggests?

I found this on the net and wondered if it was a solution to my problem as I have 8 ohm speakers?

Mono/Stereo in same cabinet
4 Musical Intrument Speakers. Mono/Stereo selectable by using a Switch. 

**Option 2**
4 - 8 ohm speakers = 16 ohms to each channel if run in Stereo, 8 ohms in Mono mode. 
*Is this in your opinion correct?* I really don't know


The Right channel jack is completely disconnected when in Mono Mode. Do Not alter this configuration (you risk doing serious damage to your power amps if wired differently). 

Mouser Electronics Sells 1/4 inch phone jacks that have a built in DPDT switch - the switch contacts are electrically isolated from the 1/4 inch Jack connection (they have to be in order for you to wire this correctly) - Marshall used this type of Jack/Switch to automatically set the speaker selection mode. They are expensive and prone to failure over time, however, using them often simplifies set-up of your rig. If you decide to use these, the Mono/Stereo switch functionality would be associated with the Right channel, where when nothing is plugged into the Right channel, the cabinet is operating in Mono Mode. 

WARNING: Never run a Tube Type power amp to the Right channel if the switch is set to Mono mode - it will damage the output transformer. 

NOTE: If you want Tweeters or Piezos in this configuration, you will need 2 of them, 1 per set of Woofers. This is because the speakers can be operated as seperate channels, using 2 completely different power amplifiers. The Tweeters or Piezos will be wired in parallel with the Woofers. The same arrangement as the above Dual Impedance systems. 

WARNING: The Left and Right jacks cannot be mounted on the same metal plate (serious damage to some power amps will occur if you do this). Use a seperate jack plate for each channel, mounted on a non-conductive surface 

*Thanks for all your help so far *


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## Mr69bungle

Hi can anyone please help? With the wiring question above please? I need advice.. 
Cheers


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## Mr69bungle

I'm going to have a go after thinking it over - i'll let you know how i got on


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## uncletiki

Is it a BAD thing to drop 1 G12M 25Watt speaker into a 4x12 cab with 3 G12T 75 Watt speakers if there all the same ohms? I could use that as my main record speaker. That would save me some cash.


----------



## Landshark

Adwex said:


> Yes, there is a problem. 2 8x10 cabs, at 4 ohms each, will equal 2 ohms when you them both into the amp. I don't know of any amp that can run at 2 ohms.
> 
> You could wire the two cabs in series with each other, then they would combine to equal 8 ohms.



This is interesting because if you have Four (4) 16 ohm cabs you can actually run two Y cables (with the four ends in the cabs) into the two cabinet outputs with the selector set to 4 ohms. Sweet set up! I just need three more cabs and two Y cables...


----------



## Landshark

Mr69bungle said:


> I'm going to have a go after thinking it over - i'll let you know how i got on



Are you wanting to run two heads through the same cab but want the cab 16 ohms mono per side? Cause if that's what you're going for then just use one side (or if you are wiring the cab top and bottom) wired in series to one of the jacks, then the other side (or bottom) in series and wired to it's own separate jack That will give you a double 2x12 in one cab with each half operating 16 ohms mono through each side individualy powered by it's own head.

Hope this is what you are wanting because if you are wanting to get four 8 ohm speakers wired to 16 ohms it can't be done. You would need 16 ohm speakers.


----------



## Landshark

uncletiki said:


> Is it a BAD thing to drop 1 G12M 25Watt speaker into a 4x12 cab with 3 G12T 75 Watt speakers if there all the same ohms? I could use that as my main record speaker. That would save me some cash.



As long as all four speakers are the same ohms rating I don't think it will hurt anything. It won't have the same output as the 75 watt speakers but if the ohm rating is the same it should be fine.


----------



## Nikki Lamar

Ive got a 50 watt head with a 4X12 16ohm 30 watt speaker cabinet. Whats the difference bewteen paralell, series , or series paralell in terms of sound? Is one better than another? I'm confused.

Thanks.


----------



## mare

Hi everybody,
I need an advice, opinion
I use Marshall jcm 800 lead 100W 2203, and jcm 800 bass cab 1935B 4x12 (celestion g12-65 1777)

So, I have opened my JCM 800 bass series 1935B 4x12" cab and I saw this!

I thought it was 16 Ohm cab, but it's, I think serial, so 4x16=64Ohm. Correct me if I'm wrong. I bought It 8 years ago, used ofcourse.

First thing that confused me was 1777 code on cone, because I thought it was code for guitar speakers, and this is bass cab, than I saw they are serial wired, and impendance selector on my amplifier is on 16 Ohm.

Questions:
1. Are these speakers suitable with my 2203?
2. Should I wire parallel/serial this speakres to get 16 Ohm total cab impendance.

PS Sorry for my english, it's not the best.


----------



## Purgasound

Jumbo Sunshade - Speaker Wiring Diagrams
there's every wiring diagram you need


----------



## deadendindustres

ANY ONE KNOW HOW TO WIRE UP 2 8 ohm celestion with 2 16ohm in one 4x12 marshall cabnet. I have looked all over the net but nothing


----------



## MartyStrat54

I posted a response to your thread. The bottom line is you can't do it without putting your amp in harm's way.


----------



## dudewheresmybass

American Viking said:


> Jumbo Sunshade - Speaker Wiring Diagrams
> there's every wiring diagram you need



hi.
noob to this forum, and i'm probabaly going to ask a complete noob question!

i have a 7200 DBS head rated to run with amin of 4 ohm load.
however i have two MBC410 cabs each rated at 4 ohms.
i want to use both cabs, so am i right in thinking that i should get my cabs rewired to run in series, and therefore push their rating/ load to 8 ohms each? (assuming the individual speaker impedances are suitable)

i hope some one is able to helps.

Cheers


----------



## Reginald

KingKong said:


> Howdi all,
> 
> I just signed up on the forums and am in need of assistance!
> 
> I just bought a nearly new tsl 100 head, and I want to make sure my cabinet is wired for 16 ohm impedance. I'm attaching a pic. The lower terminal of the upper right speaker (as you look at the pic) is positive. I believe the top speaker terminals on the speakers on the left are positive (marked with red dot). The speakers are each 16 ohm. I believe the top two are wired together in series, the bottom two are wired together in series, and the upper pair is wired to the lower pair in parallel.
> 
> If anyone could take a look at this and share an opinion I'd appreciate it!
> 
> I'm thinking it's 16 ohms total impedance, but I'd like another opinion before I use the 16 ohm output from the tsl 100.
> 
> Thanks!
> Kong




What's difference there's between wire connection of both?Which's in series/parallel and which in parallel?
And with which between them the amp/the OTtransformer ,the whole circuit too)work much less hard with? I'm sorry I don't able to insert also cab photo of him,help me,please....but you can see at the first page on this topic


----------



## Reginald

what's the differences?


----------



## Wilder Amplification

Reginald said:


> what's the differences?



I think this is what you meant to draw.











What's the difference? Well if you take the Series Parallel drawing and you add a wire between the series connection point of the left pair of speakers and the series connection point of the right pair, you now have Parallel Series.

Other than that...they both give the same total load impedance out, which will be equal to the impedance of one of the 4 speakers if they're all equal impedance, which they should be. The amp don't know the difference between the two. Some people claim there's a tonal difference but personally I don't buy it.


----------



## Purgasound

dudewheresmybass said:


> hi.
> noob to this forum, and i'm probabaly going to ask a complete noob question!
> 
> i have a 7200 DBS head rated to run with amin of 4 ohm load.
> however i have two MBC410 cabs each rated at 4 ohms.
> i want to use both cabs, so am i right in thinking that i should get my cabs rewired to run in series, and therefore push their rating/ load to 8 ohms each? (assuming the individual speaker impedances are suitable)
> 
> i hope some one is able to helps.
> 
> Cheers



If both cabinets are 4x10 then you can rewire them from 4ohm to 16ohm and when using both cabinets (now at 16) you set the head to 8ohms. 
Here is a link that has the diagram that you need. I believe the Jumbo Sunshade has left this one out. 
Wiring a 4 X 12 Speaker cabinet

If the speakers are 4ohms each, then you need to wire like this...
*Four 4ohm speakers wired in series to yield a final load of 16ohms*





If the speakers are 16ohms each then you are more than likely wired like this... *edit, thanks JohnH!
*Four 16ohm speakers wired in parallel to yield a final load of 4ohms*





So you need to change to this...
*Four 16ohm speakers wired in series/parallel to yield a final load of 16ohms*





I highly recommend getting a multimeter if you don't already have one and always check the impedance of any finished work you have performed. I do, every time just to be 100% sure.


----------



## JohnH

careful AV! that second diagram is 4x16 Ohms to give 4Ohms total
J


----------



## Wilder Amplification

JohnH said:


> careful AV! that second diagram is 4x16 Ohms to give 4Ohms total
> J



Good catch on that typo!


----------



## Buggs.Crosby

Also from the Shavano site is this jem
Shavano Music Online - Speaker Wiring; Impedance Calculator
it is great for figuring out mismatched speaker impedance


----------



## TheGummy

hello, I've got a 2x12 master volume combo and have noticed that the two speakers sound drastically different.

its not necessarily a bad sound, in fact its quite nice, but im concerned that it's a sign that something isn't right. the amp was serviced before i bought it so i would have thought it was all good.

the amp seems to be wired to one speaker (one with a fuller, clearer sound) first and then the cables go on to the other speaker (duller and muddier)

i believe that the document that came with it said they were wired in parallel, but i dont know enough to recognise whats going on.

would appreciate any help,

Thanks.


----------



## Wilder Amplification

TheGummy said:


> hello, I've got a 2x12 master volume combo and have noticed that the two speakers sound drastically different.
> 
> its not necessarily a bad sound, in fact its quite nice, but im concerned that it's a sign that something isn't right. the amp was serviced before i bought it so i would have thought it was all good.
> 
> the amp seems to be wired to one speaker (one with a fuller, clearer sound) first and then the cables go on to the other speaker (duller and muddier)
> 
> i believe that the document that came with it said they were wired in parallel, but i dont know enough to recognise whats going on.
> 
> would appreciate any help,
> 
> Thanks.



If you have 1 wire going from the positive terminal of 1 speaker to the positive terminal of the other speaker, then a 2nd wire from the negative terminal of 1 to the negative terminal of the other, that's parallel wiring.

If you have a jumper wire connected from the negative of one speaker to the positive of the other speaker, then it's series wired.

If they're 16 ohm speakers, they should be wired parallel to give you an 8 ohm load.

If they're 4 ohm speakers, they should be wired in series to give you an 8 ohm load.

8 ohm speakers can be wired either or, and in parallel will give you 4 ohms while giving 16 ohms in series.

If you can post up a couple of pics of the insides of the cab I can tell you exactly what you have goin' on.


----------



## Purgasound

JohnH said:


> careful AV! that second diagram is 4x16 Ohms to give 4Ohms total
> J



Ooops! Thanks John, I totally missed that. Last post before I went to bed last night. I went back and corrected it now.


----------



## enteroutside

Hi guys, very interesting topic!

here is my question/case

i have a 8240 Valvestate (2 40W speakers 4Ohm each) and i want to use it as a cabinet for my 100W head.

apart from the Watts that don't fit (but i won't push the amp to hard so it wouldn't be a problem right?) how should i connect the speakers?

currently the valvestate has 2 outputs (1 red, 1 black) that i assume are 2 seperate 4 Ohm speakers.

Should i wire them is series and connect one of the outs to the head at 8 Ohm? How would the connection be and which output (red or black) should i choose? I can't connect both of them coz my amp doesn't have a 2x4 Ohms choice ain't it right?

Thanks in advance

K.


----------



## Wilder Amplification

enteroutside said:


> Hi guys, very interesting topic!
> 
> here is my question/case
> 
> i have a 8240 Valvestate (2 40W speakers 4Ohm each) and i want to use it as a cabinet for my 100W head.
> 
> apart from the Watts that don't fit (but i won't push the amp to hard so it wouldn't be a problem right?) how should i connect the speakers?
> 
> currently the valvestate has 2 outputs (1 red, 1 black) that i assume are 2 seperate 4 Ohm speakers.
> 
> Should i wire them is series and connect one of the outs to the head at 8 Ohm? How would the connection be and which output (red or black) should i choose? I can't connect both of them coz my amp doesn't have a 2x4 Ohms choice ain't it right?
> 
> Thanks in advance
> 
> K.



First off, if you're gonna use that as a cab, the amp that will be powering the speakers will have no connection to the amp whatsoever. If the speakers have a 1/4" male plug on them, you would need to get a 1/4" female to female adapter to allow you to plug a speaker cable into the speakers.

Also, the speakers would have to be series wired since they're 4 ohms, giving you a total 8 ohm load.


----------



## enteroutside

actually the way 8240 is made (correct me if i'm wrong) is that 2 jacks come out of the speakers so i could connect them direct to the head amp (one of them). If i use a Y to connect both of them and then connect the single out to the head is this a series connection?

2x4 Ohm cabs - Y adapter - one 1x8 Ohm out to head. is it correct?

if not how can i connect them i series having only one of the jacks as output?..sorry, is it clear what i'm asking? If not iìll try to be more specific.

thanks


----------



## TheGummy

Wilder Amplification said:


> If you have 1 wire going from the positive terminal of 1 speaker to the positive terminal of the other speaker, then a 2nd wire from the negative terminal of 1 to the negative terminal of the other, that's parallel wiring.
> 
> If you have a jumper wire connected from the negative of one speaker to the positive of the other speaker, then it's series wired.
> 
> If they're 16 ohm speakers, they should be wired parallel to give you an 8 ohm load.
> 
> If they're 4 ohm speakers, they should be wired in series to give you an 8 ohm load.
> 
> 8 ohm speakers can be wired either or, and in parallel will give you 4 ohms while giving 16 ohms in series.
> 
> If you can post up a couple of pics of the insides of the cab I can tell you exactly what you have goin' on.



yep, that would fit what i thought. that would make it 2x 16 ohm speakers in parallel. cheers.

would this wiring account for the difference in the two speakers? the first one in the chain being clearer and has a slightly higher output.

or is this just down to some old, abused speakers? as long as it's not a sign of something being wrong or it could lead to other problems, then i'm not fussed.


----------



## Wilder Amplification

enteroutside said:


> actually the way 8240 is made (correct me if i'm wrong) is that 2 jacks come out of the speakers so i could connect them direct to the head amp (one of them). If i use a Y to connect both of them and then connect the single out to the head is this a series connection?
> 
> 2x4 Ohm cabs - Y adapter - one 1x8 Ohm out to head. is it correct?
> 
> if not how can i connect them i series having only one of the jacks as output?..sorry, is it clear what i'm asking? If not iìll try to be more specific.
> 
> thanks



No, using a Y parallels them. 

To series wire them with 1 jack, connect the jack's positive to the positive of one speaker, then connect the jack's negative to the negative of the opposite speaker. Then connect a wire between the positive and negative terminals that aren't connected to the jack.


----------



## Wilder Amplification

TheGummy said:


> yep, that would fit what i thought. that would make it 2x 16 ohm speakers in parallel. cheers.
> 
> would this wiring account for the difference in the two speakers? the first one in the chain being clearer and has a slightly higher output.
> 
> or is this just down to some old, abused speakers? as long as it's not a sign of something being wrong or it could lead to other problems, then i'm not fussed.



Well that could be the case. The wires that run from one speaker to the other only have to carry the current for one speaker, whereas the wires running from the amp to the first speaker has to carry the current for both speakers. I would try increasing the size of the wires running from the amp to the first speaker to find out and see if you hear a difference.


----------



## enteroutside

Wilder Amplification said:


> To series wire them with 1 jack, connect the jack's positive to the positive of one speaker, then connect the jack's negative to the negative of the opposite speaker. Then connect a wire between the positive and negative terminals that aren't connected to the jack.



Great, thank you. Being 2 40w speakers now the cabin becomes 80W by connecting the two speakers togehter?



Wilder Amplification said:


> No, using a Y parallels them.


is there a way to series the two line cables with an external adapter?

Thanks so much for the info.


----------



## Wilder Amplification

enteroutside said:


> Great, thank you. Being 2 40w speakers now the cabin becomes 80W by connecting the two speakers togehter?
> 
> 
> is there a way to series the two line cables with an external adapter?
> 
> Thanks so much for the info.



Not that I'm aware of. Don't think they ever made a series adapter.


----------



## dudewheresmybass

thanks for your insight American Viking - cheers


----------



## Donavan

Hi guys ,I'm new to this Forum... Kinda. I have used it as a reference to help me out a few times really good info here. Anyways i need a bit of help to insure I don't blow up my amp. I have three cabinets, one 2 X 12 (16 ohms), one 1X12(16 ohms) and one 4X 10(8 ohms).Can I run the 2X 12 in parallel with the 1X 12 on one input of my head and the 4X 10 on the other input? The inputs are in parallel.And should this be set on 4 ohms? The head is a converted jcm 900 duel reverb combo(yeah I know everybody hate's em) with the 4 and 8 ohm switch.I attached a very crude mess of a diagram to show ya what i am trying to do. Try not to get too jealous of my paint program skills!!!


----------



## Wilder Amplification

Donavan said:


> Hi guys ,I'm new to this Forum... Kinda. I have used it as a reference to help me out a few times really good info here. Anyways i need a bit of help to insure I don't blow up my amp. I have three cabinets, one 2 X 12 (16 ohms), one 1X12(16 ohms) and one 4X 10(8 ohms).Can I run the 2X 12 in parallel with the 1X 12 on one input of my head and the 4X 10 on the other input? The inputs are in parallel.And should this be set on 4 ohms? The head is a converted jcm 900 duel reverb combo(yeah I know everybody hate's em) with the 4 and 8 ohm switch.I attached a very crude mess of a diagram to show ya what i am trying to do. Try not to get too jealous of my paint program skills!!!



Yes set it to 4 ohms and all should be good.


----------



## SaltetOhlsson

Hallo people, Can anyone help me to find a link to the original wiring scheme for an 1984 JCM 800 4x12" 1935B cabinet (Celestion g12-65w 15 ohms Code T3101) *Thanx in advance/Mike*


----------



## Wilder Amplification

SaltetOhlsson said:


> Hallo people, Can anyone help me to find a link to the original wiring scheme for an 1984 JCM 800 4x12" 1935B cabinet (Celestion g12-65w 15 ohms Code T3101) *Thanx in advance/Mike*



Either of these two will work and give you a 15 ohm load. The schematic shows 16 ohms, but it also uses 16 ohm speakers. These schemes will give you the impedance of one of the speakers as the total load provided all speakers are of matching impedance.


----------



## SaltetOhlsson

Thanx, Jon! Much appreciated. Cheers Mike


----------



## Dave666

How can you see the polarities on speakers?


----------



## Dave666

About that previous reply: Nevermind, just found them...


----------



## Reginald

Landshark said:


> As long as all four speakers are the same ohms rating I don't think it will hurt anything. It won't have the same output as the 75 watt speakers but if the ohm rating is the same it should be fine.



Yeahhh friend ...I feel a MAGIC 'CHEWY',GUMMY,'RUBBERY' ATTACK especially in Superbasses and Super Tremolos.


----------



## dwpropserv

Hi all, i have built 2 x 2x12 cabs and im gonna wire them both in paralell, and run them both at 4 ohms. All i need are 2 of the jack plates with an input and an output jack. Does anyone know where i can get one of these. Prefferably in the uk. cheers people


----------



## Speakerbum

Here's a nice way of *wiring two 8 ohm speakers using 3 inputs*.

You can use both at 16 ohms or each one separately at 8 ohms each. The article shows the connection diagram and the "blank cabinet dish" you can order form PartsExpress.

Chances are that you can find that from a UK supplier.

SB.


----------



## markymarc1979

This is probably a noob thing to ask but I would like to get it right, I have installed 2 Eminence Private Jacks (8 ohms) into a stock 1936, the wiring has been left as it was, the G12-75's that I took out were (16 ohms). Is my cab now 8 ohms stereo and 4 ohm mono, Or am I just stupid? Thanks for any help.


----------



## Wilder Amplification

markymarc1979 said:


> This is probably a noob thing to ask but I would like to get it right, I have installed 2 Eminence Private Jacks (8 ohms) into a stock 1936, the wiring has been left as it was, the G12-75's that I took out were (16 ohms). Is my cab now 8 ohms stereo and 4 ohm mono, Or am I just stupid? Thanks for any help.



Depending on how they wired it at the jack board. However, with 8 ohm speakers it can be wired 16 ohms mono (speakers series wired) and 8 ohms stereo (each individual speaker).

If those G12T-75s were 16 ohms then the cab was more than likely 8 ohms mono and 16 ohms stereo. Of course they could've had it wired something stupid like 32 ohms mono and 16 stereo, but I doubt they did that.

If that cab with the 16 ohmers was 8 ohms mono/16 ohms stereo, then with 8 ohmers it would be 4 ohms mono/8 ohms stereo. Best way to tell is to plug a cable in with the cab in mono mode and measure the DC resistance of the cab with a multimeter. The reading will be slightly lower than the nominal impedance rating. If the total mono impedance is 4 ohms it may read somewhere around 2-3 ohms whereas if it's 16 ohms mono it will read around 14 ohms.


----------



## markymarc1979

Wilder Amplification said:


> Depending on how they wired it at the jack board. However, with 8 ohm speakers it can be wired 16 ohms mono (speakers series wired) and 8 ohms stereo (each individual speaker).
> 
> If those G12T-75s were 16 ohms then the cab was more than likely 8 ohms mono and 16 ohms stereo. Of course they could've had it wired something stupid like 32 ohms mono and 16 stereo, but I doubt they did that.
> 
> If that cab with the 16 ohmers was 8 ohms mono/16 ohms stereo, then with 8 ohmers it would be 4 ohms mono/8 ohms stereo. Best way to tell is to plug a cable in with the cab in mono mode and measure the DC resistance of the cab with a multimeter. The reading will be slightly lower than the nominal impedance rating. If the total mono impedance is 4 ohms it may read somewhere around 2-3 ohms whereas if it's 16 ohms mono it will read around 14 ohms.



Thanks for your help. I'm 99 sure it was wired 8 ohms mono and 16 Stereo, so I'm assuming it's now 8 ohm stereo and 4 ohm mono. But I would like to check it with a multi meter, I have my one that belonged to my father, the only problem is it's one of those mega button auto ranging things so I have no idea where to set it for reading DC resistance!!


----------



## Wilder Amplification

markymarc1979 said:


> Thanks for your help. I'm 99 sure it was wired 8 ohms mono and 16 Stereo, so I'm assuming it's now 8 ohm stereo and 4 ohm mono. But I would like to check it with a multi meter, I have my one that belonged to my father, the only problem is it's one of those mega button auto ranging things so I have no idea where to set it for reading DC resistance!!



Look for the "omega" sign on the range dial (looks like a Greek horseshoe ). That's your "Ohms" setting.


----------



## markymarc1979

Actually, my brain clicked into gear, it is 4 ohm mono and 8 stereo, I read just over 4 ohms in mono and just over 8 in stereo. thanks for your help!!


----------



## eltelengland

Hello Chaps,

New forum member here. Here's a thread related question. I have a JVM205C standard with 1 off G12C and 1 off G12H. These are wired in series 8 + 8 = 16ohms. Can someone advise how different the combo is likely to sound if I rewire it to run the speakers in parallel ie 8 / 8 = 4 ohms. The combo has the avaliable O/P set-up. Running into 4ohms means the current in the O/P circuits ie amplifier speaker O/P transformer secondary and speaker coils will be higher. Will this warm up the sound in a good way as I suspect the speaker response will be rolled off slightly or will it introduce more non-harmonic type distortion due to the increased current running thorugh the same individual speaker impedances. 

I guess I'll have to try it, but does anybody know if there's a general principle here ?

Thanks,

El Tel England


----------



## eltelengland

Guy's,

Correction to the above, the current through the speaker coils will be the same it's just the amplifier O/P transformer that's operating at a higher current. Question still stands though, is there a general principal here or is each configuration equally good.

Thanks,

El Tel England


----------



## Tubedude

q moved.


----------



## JeromeBasel

Hi, first time here. simple question, please simple answer:
4x8 Ohm Cab, in Mono/parallel - connecting + to + and - to - ? Right?
But which amp setting? got 4 or 8 ohm on the amp.
and 2x8 Ohm & 2x16 Ohm, which setting?
Thank you guys.


----------



## Wilder Amplification

JeromeBasel said:


> Hi, first time here. simple question, please simple answer:
> 4x8 Ohm Cab, in Mono/parallel - connecting + to + and - to - ? Right?
> But which amp setting? got 4 or 8 ohm on the amp.
> and 2x8 Ohm & 2x16 Ohm, which setting?
> Thank you guys.



Lets see....4 x 8 ohm cabs would drop your total load down to 2 ohms (8 ohms / 4 cabs = 2 ohms) so this could not be used on one head.

2 x 8 ohm cabs = 4 ohms (8 ohms / 2 cabs = 4 ohms) so you would set the selector on the amp to 4 ohms.

2 x 16 ohm cabs = 8 ohms (16 ohms / 2 cab = 8 ohms) so you would set the selector on the amp to 8 ohms.

So on your amp the MOST you could run would be 4 x 16 ohm cabs (4 ohms total) or 2 x 8 ohm cabs (4 ohm total) to keep from going below 4 ohms since 4 ohms is the lowest load that your amp can drive safely.


----------



## Lucius Junius

Hi, new to the forum.

I have a JVM205H with a 1960A cab.

Probably someone has asked this before but ... what would be the difference in sound between these two connections?

1) 1x16 Ohm out to 16 Ohm mono in
2) 2x8 Ohm out to 8 Ohm stereo in

Will I be able to hear the difference? It's the same cabinet ... 

Any recommendations?

Thanks


----------



## Adwex

Lucius Junius said:


> Hi, new to the forum.
> 
> I have a JVM205H with a 1960A cab.
> 
> Probably someone has asked this before but ... what would be the difference in sound between these two connections?
> 
> 1) 1x16 Ohm out to 16 Ohm mono in
> 2) 2x8 Ohm out to 8 Ohm stereo in
> 
> Will I be able to hear the difference? It's the same cabinet ...
> 
> Any recommendations?
> 
> Thanks


 
First, 2x8 ohm out will not equal 8 ohms, it will equal 4 ohms.

Second, there will be absolutely no difference.


----------



## JeromeBasel

*SPEAKER WIRING, Diagramm*

Hi, here is another Link to a good, easy diagram for wiring
Wiring Diagrams

maybe it helps


----------



## JeromeBasel

*How to connect 2 cab's with different speakers?*

Hi
hope for you help again. I've got a cab loaded with 4x12" 16Ohm speakers, wired mono/parallel = 4 Ohm (output amp)
The 2. cab is loaded with 2x12" 8Ohm speakers (like the Marshall 1936).
How can I connect both cab's, anybody has a wiring schema/diagram for that case? What for output (ohm) on the amp I should select?
Thanks for you help, Jerome, Switzerland


----------



## Wilder Amplification

*Re: How to connect 2 cab's with different speakers?*



JeromeBasel said:


> Hi
> hope for you help again. I've got a cab loaded with 4x12" 16Ohm speakers, wired mono/parallel = 4 Ohm (output amp)
> The 2. cab is loaded with 2x12" 8Ohm speakers (like the Marshall 1936).
> How can I connect both cab's, anybody has a wiring schema/diagram for that case? What for output (ohm) on the amp I should select?
> Thanks for you help, Jerome, Switzerland



First, the 4x12 cab should be rewired series/parallel. This will give you a 16 ohm load.






Second, the 2x12 will have to be wired in series. This will give you a 16 ohm load.







You would then plug them both into the amp and set the amp for 8 ohms.


----------



## harpmaster

Hi I just purshased a 15 watt valve combo amp it has a ext speaker out that says 8 ohm min I have a mg15 mini stack the speaker cabinets are 16 ohm each they have only 1 input in each could I come out of the amp with a y then go to the two cabinets with out hurting anything would that stay at 16 ohms?


----------



## Beynon5

Hey guys can anyone help me, I used a ohm meter on my cab to find out the impedance due to my amp having a funny spell of wierd noises (tip from a guitar tech) and it mesured 9.67 .. should I be using this on the 8ohm setting? 

thanks


----------



## Wilder Amplification

Beynon5 said:


> Hey guys can anyone help me, I used a ohm meter on my cab to find out the impedance due to my amp having a funny spell of wierd noises (tip from a guitar tech) and it mesured 9.67 .. should I be using this on the 8ohm setting?
> 
> thanks



Honestly I'd call into question whether the cab is wired correctly or not, whether you have speakers of mismatched impedance or whether you may/may not have a blown speaker. Usually on 8 ohm cabs you'll see somewhere in the neighborhood of 6-7 ohms DC resistance while seeing 12-14 ohms DC resistance on a 16 ohm cab.

Having speakers of mismatched impedance and/or having one/more that may be blown will also make the reading a "non-standard" value.

If you're able to open the cab and take pics we can tell you if it's wired correctly or not plus you'll be able to figure out if the speakers are of mix/matched impedance.


----------



## Beynon5

Okay thanks, ill get some pictures up as soon as I can , its a hughes kettner cab with 2 old goodmans speakers in it and 2 celestions , im a totall newbie to the whole cab ohm wiring so iv just left it as I had it and used the input I was told was 8ohm , I'll get the pics up as soon as I can , 

Thanks


----------



## Viking62

Is it ok to have 2 x G12M 8 ohm 25 watt 12" Greenbacks and 2 x G12M 16 ohm Greenbacks 12" 25 watt in the same Cab?


----------



## Wilder Amplification

Viking62 said:


> Is it ok to have 2 x G12M 8 ohm 25 watt 12" Greenbacks and 2 x G12M 16 ohm Greenbacks 12" 25 watt in the same Cab?



You CAN do that, but it will give the cab a non-standard impedance of 5.33 ohms, which can be ran on the 4 ohm tap. Also, if you run a second cab with that cab, the 2nd cab HAS to be a 16 ohm cab and you'll run them on the 4 ohm tap.


----------



## dugger

So please tell me if this thought of mine is right or wrong...
you will not find an 8 ohm speaker, or any combination there of, in a 4x12 4ohm cab? (straight plug in, not mono/stereo)


----------



## maggot

Hi!

Which is the correct wiring for my jcm900 amp + 1936 2x12 cabinet. I had the amp putting out 8 ohms, and the cable goin to cabinets mono input(8 ohms), and im noticing some heating in the amp... help!


----------



## rockinr0ll

maggot said:


> Hi!
> 
> Which is the correct wiring for my jcm900 amp + 1936 2x12 cabinet. I had the amp putting out 8 ohms, and the cable goin to cabinets mono input(8 ohms), and im noticing some heating in the amp... help!



What speakers are you using in the 1936? If you are using x2 16 ohm speakers equal or greater to the watts of the amp there should be no problem. If it is coming from the head itself then maybe the tubes are biased a little hot. My tubes get pretty hot.


----------



## maggot

I believe that the speakers are Celestion G12T-75 8 ohm.


----------



## rockinr0ll

If they are indeed 8ohm(s) than running them mono would be 4 ohm(s). Which would be bad for the head.


----------



## Wilder Amplification

rockinr0ll said:


> If they are indeed 8ohm(s) than running them mono would be 4 ohm(s). Which would be bad for the head.



Not if he switches it to the 4 ohm setting. And if they are in fact 8 ohms, more than likely they series wire in mono mode, which would be 16 ohms.


----------



## Adwex

My 1936 has a pair of 16 ohm G12T-75s, wired in parallel.
8 ohms Mono, 16 ohms each side stereo.


----------



## rockinr0ll

Wilder Amplification said:


> Not if he switches it to the 4 ohm setting. And if they are in fact 8 ohms, more than likely they series wire in mono mode, which would be 16 ohms.



If it is a current 1936 with stereo it should be* 16 ohm stereo and 8 ohm mono*. Assuming he was correct about the speakers being 8 ohm each and it is still a current reissue than it would be 8 ohm stereo and 4 ohm mono. If it is stock than it is indeed the first and there is no problem.


----------



## rockinr0ll

Adwex said:


> My 1936 has a pair of 16 ohm G12T-75s, wired in parallel.
> 8 ohms Mono, 16 ohms each side stereo.


----------



## maggot

Adwex said:


> My 1936 has a pair of 16 ohm G12T-75s, wired in parallel.
> 8 ohms Mono, 16 ohms each side stereo.



I checked it, this is the same cabinet as mine. Which is the best way to wire my amp?


----------



## buzz

stoopid question time...................

is there any way of changing the stock impedance of a speaker...say making a 8ohm into a 16ohm.....or is it fixed by the winding of the coil


----------



## Wilder Amplification

buzz said:


> stoopid question time...................
> 
> is there any way of changing the stock impedance of a speaker...say making a 8ohm into a 16ohm.....or is it fixed by the winding of the coil



Fixed by the winding of the coil.


----------



## buzz

thought so. thanx anyway


----------



## xanda-panda

*Please help, I'm a wiring idiot*

Hello, I'm new on here. I'm hoping one of you can tell me what ohmage my cabinet is.

It's a 1960A and I have replaced the stock 16ohm speakers with 8ohm speakers. I'm attaching a few pictures of the inside of the cab as well as a crude diagram of it. The bit that's really throwing me is the strange Marshall switch plate thing with the two jack inputs.

After doing a bit of research I've learned to only use the "16ohm Mono" jack (on the right) and have it set to 'mono' and have taped over the stereo jack and switch. I won't be using the stereo side ever. With that in mind, could you tell me what ohmage my cab is?

http://i5.photobucket.com/albums/y151/xandapanda/DSCF1542.jpg

http://i5.photobucket.com/albums/y151/xandapanda/DSCF1537.jpg

http://i5.photobucket.com/albums/y151/xandapanda/DSCF1543.jpg

http://i5.photobucket.com/albums/y151/xandapanda/cabinetwiring.jpg


Thanks alot guys.


----------



## Rob_Hermans

Correct me if I'm wrong, but it's calculated this way for speakers wired in parallel:

Circuit load is equal to the resistance (Ohms) of the speaker DIVIDED by the number of speakers

It's calculated this way for speakers wired in series:

Circuit load is equal to the resistance (Ohms) of the speaker MULTIPLED by the number of speakers

I think the 1960A has series/parallel wiring, so assuming you didn't change the wiring layout on the speakers, with the cab running in mono you would have 4 x 8 Ohm speakers, resulting in an 8 Ohm load.

Perhaps you should read the previous posts in this thread - you'll find a lot of answers and good links!

Hope that helps


----------



## mkxxx

Hi - I'm new.

My question is about mixing speakers, notably Celestion Greenbacks and Vintage 30s - for a start. I'd like to have different types of speakers, to get different tones for recording (close-micing single speakers).

The rig in question: Marshall: JMP-1, 9100 MonoBloc 2x50W, 2x 1912 @ 12" Celestion G12B-150 (150W each).

I'm trying to get and record:

'speaker breakup'
'sag'/'saturation' from the power amp
more varied Classic Rock and Hard Rock tones (AC/DC, Judas Priest, Iron Maiden, Deep Purple, etc.).

My current speakers aren't too well known or highly regarded. I don't play live. I record a lot at home. I *can* turn the amp way up.

I've read the whole thread, but not understood the implications of all the information. I get the impedance calculations, the wattage is harder for me to follow.

My direct approach would be: buy a 2x12" and put one of each type of speaker in, impedances matching. I know the speakers interact in the cab - is that acoustically, because they share the same box, or is that electrically, because the current goes through two coils? Would they be better wired in series or in parallel (how does that affect the wattage)?
I know their wattages are different. Would I be destroying the Greenback when turning up the amp?
I know the sounds of the above-mentioned bands were most probably recorded from 4x12" cabs, but I just don't need/want that many speakers of the same kind, as I'm only close-micing one speaker.
As I hate to have unused gear lying around, how well would the G12B-150 speakers do with a bass amp? In the current pair of small cabs, or in a single 2x12" bass cab? What else could I do with the current pair of cabs?

Thanx in advance!

ciao,
mkxxx


----------



## thrawn86

mkxxx, I think the question you've asked might be better answered in this thread:

http://www.marshallforum.com/cabinets-speakers/8492-everything-anything-about-speakers-12.html

Just pop over there and copy and paste your post into that thread. No need to read all the way through it; Marty can help you out tremendously.


----------



## mkxxx

Thanx, thrawn86!



> mkxxx, I think the question you've asked might be better answered in this thread:
> http://www.marshallforum.com/cabinets-speakers/cabinet...eakers-12.html
> Just pop over there and copy and paste your post into that thread. No need to read all the way through it; Marty can help you out tremendously.



OK, I'll try my luck there ... I did start reading it, but found this thread, too. I just hope I don't end up asking something they've explained to every newb they get.


----------



## Michael1987xl

Reported.

Ed Hardy sucks, by the way, you spamming ass.


----------



## Adwex

No need to respond, just report.
They can't hear you.


----------



## Eugene Tooms

Hello all,

This may seem rehashed to most of you but feel where I'm coming from since I'm sorta new to this. I really just need like a picture of what the original wiring setup for a 1960a cab is. I had to take it all apart to put a new grill cloth on and I should have taken a picture of it before I did. Now after trying to find the correct wiring for hours I'm kicking myself that I didn't take a picture.

Also, am I supposed to be using the 4Ohm input of the 16Ohm input. I'm only using 1 cabinet.

From the kindness of your hearts.


TOOMS


----------



## davidwillson

Guv'nor said:


> 1 / (1/16 + 1/16 ) = 1 / (0.0625 + 0.0625) = 1/0.125 = 8 Ohm Load
> 
> You're ok.



I am looking at buying a cab that has 2 16ohm speakers in it, am i correct in saying my amp should be set at 8 ohms?

Thanks


----------



## kanders1

Hi, everyone - A couple of stupid questions:

1. I have my 1987 head going to one 8-ohm cabinet. If I was to plug a DI box that uses a dummy load into my second speaker output, leaving the 8-ohm cab plugged into the first, I assume the DI device should probably have an impedance of 8 ohms and I would switch the amp's ohm selector from 8 to 4 ohms. The speaker outputs are wired in parallel, correct?

2. Question 1 is based on a crazy idea I had, which basically involves removing my stereo time-based effects from my pedal chain, sending my second speaker output to a DI device then to a stereo mixer, adding my stereo effects to the mixer's effects send, returning the wet-only stereo effects signal to 2 channels on the mixer, sending the mixer output to a stereo amp, which then drives a stereo cab I made by rewiring an old 4x12 Ampeg cab. Has anyone ever tried anything like this, i.e. adding stereo delay, reverb, etc. after the guitar amp using a DI/attenuator/dummy load, rather than a mic, into a mixer to stereo amp to stereo cab?

I can't find much information on using a DI device AND a cabinet plugged into the speaker outputs at the same time. 

Thanks for any input or suggestions for good mental health treatment facilities.

Kevin


----------



## Stratguy

Hi guys 

I have a few wiring questions - my 1960A cab has 4 Celestion T-75's in it. They are all 16 ohm speakers and my head is set at 16 ohms. Is this a combination of series / parrell wiring? I'm sure it has not been touched since it left the factory. 

I will shortly also have a 2 x 12 Avatar cab with two 8 ohm Eminence Guvnors wired in series for 16 ohm. In order to run both cabs at the same time, do i change the head setting to 8 ohms? 

Will there be any issues running both cabs at the same time? And finally, i'm guessing if i just want to run the 2 x 12 alone, i need to set the head back to 16 ohm? 

Thanks in advance for reading this and i look forward to your suggestions.

Cheers.....

Al


----------



## chuckharmonjr

OK...Im going on memory here(too damned lazy to go turn my stack around...lol)...on the 1960 cabs....there are 3 jacks in the jack plate. In mono mode...the one closest to the switch is all 4 speakers in either 4 or 16 ohm (depending on the switch setting) and the middle one becomes a pass-thru for parallelling. In other words...switch set to 16ohms...head from 8 ohm jack at 8ohms on the switch to cab input...middle jack out to other cab.


----------



## Adwex

Stratguy said:


> Hi guys
> 
> I have a few wiring questions - my 1960A cab has 4 Celestion T-75's in it. They are all 16 ohm speakers and my head is set at 16 ohms. Is this a combination of series / parrell wiring? I'm sure it has not been touched since it left the factory.
> 
> I will shortly also have a 2 x 12 Avatar cab with two 8 ohm Eminence Guvnors wired in series for 16 ohm. In order to run both cabs at the same time, do i change the head setting to 8 ohms?
> 
> Will there be any issues running both cabs at the same time? And finally, i'm guessing if i just want to run the 2 x 12 alone, i need to set the head back to 16 ohm?
> 
> Thanks in advance for reading this and i look forward to your suggestions.
> 
> Cheers.....
> 
> Al



Your answers to your own questions are correct.

Yes, they are wired in series/parallel in the 1960 4x12...which results in the entire combination of speakers equalling the impedance of one of them.

Yes, your 16 ohm 2x12 and your 16 ohm 4x12 both connected to the amp will result in an 8 ohm load.

Yes, the 2x12 alone will be 16 ohms.

The only issue to even consider with running both cabs will be that since both cabs are the same impedance, the power from the amp will be absorbed by both CABS equally. This implies that each speaker in the 2x12 will absorb twice the power that each speaker in the 4x12 will get. For a 100 watt amp, the 2x12 will get 50 watts total, so each speaker will get 25 watts. In the 4x12, each speaker will get 12.5 watts. As long as the speakers in the 2x12 are rated for more than 25 watts, you're ok.


----------



## chuckharmonjr

Yeah Ad...but shouldnt he do the pass-thru at the top cab thru the switch plate to parallel both cabs?


----------



## chuckharmonjr

Wait a minute...hold the phone sports fans...I forgot to ask a fundamental question here. What amp are you running? I run a DSL which has 1 16ohm out and 2 8/4 ohm outs. If your amp has two outputs period and an ohm selector...hook each 18 ohm cab to one output each and set the selector to 8 ohms. If you have a DSL/TSL, then what I was talking about above applies. My bad...I was not only lazy in not looking at my cabs, I was also lazy in asking questions.


----------



## SwaniusMaximus

Hi, I just bought an empty cab and I want to wire 4 16 ohm speakers to 4 ohms. So would I just connect all the positives to each other and all the negatives to each other? or is there a certain order I need to connect them in? Also, when I connect all the speakers to the jack, how should i connect it? If I connect it incorrectly, will is sound strange?


----------



## chuckharmonjr

All the plusses connect together to the tip connector on the jack. All the minuses connect together to the shaft side of the jack. 4 Ohms the easy way.


----------



## SwaniusMaximus

alright, how do I know which tab is which on the jack? It's not totally clear to me just looking at the jack


----------



## chuckharmonjr

if it's an enclosed jack, easiest way would be to rig a plug with a pigtail on it...IE; soldered into the plug than the other end of the cable exposed and stripped back. That way you could ohm it out with a meter. I dont really think it makes that big a difference in the long run so long as you are using only 1 cab.


----------



## yes9310

superleadfixer said:


> Also the serie/parallel combination in a 4x12 cab will have a draker sound and a little harcher, if your amp (set up) is too dark one way to help this out would do a Parallel/series connection instead, that will give a little bit cleaner and brighter sound.........



Does everyone agree with this? My 4x12 Cab of Pre-Rola G12H30 75Hz sounds really dark for some reason but when I plug the same JTM 45/100 head into a 2x12 cab loaded with V30s, it's Ultra Bright. Could it be the Series/Parallel combo making it sound so dark or maybe need smaller or larger diameter wire?


----------



## shawntmartin

Adwex said:


> American Viking speaks the truth...words to live by.
> 
> Always match impedance.
> 
> Always.


 
How do you match impedance when you have four G12M-70 15ohm speakers? How do you can't get 4, 8, or 16 ohms out that?


----------



## chuckharmonjr

Shawn, 15 or 16 actually is the same set-up as far as the head sees.


----------



## shawntmartin

Having a problem with my amp cutting out after wiring for 4 ohm. I'm using a 4ohm compatible amp. I have 4.. 15 ohm speakers that are wired in series (all positives go to each other and all negatives tie with each other) which should be 4 ohms. Check out the pics. The positive is the wire on the left in pic #1 and the negative is the wire on the left in pic #2.

Correct? If so... why is this cutting out?


----------



## chuckharmonjr

Whats your amp set for on the output impedance?


----------



## shawntmartin

chuckharmonjr said:


> Whats your amp set for on the output impedance?


 
The same 8ohm speaker output can be used for 4ohm. Here's a link to the back panel. Its the last pic on the right.

http://www.adverts.ie/guitar-bass/ibanez-tbx150h-150-watt-toneblaster-guitar-head/375739


----------



## Michael. L.

Hey Guv'nor, 
Quick inquiry,
2 x 12 inch Celestion greenbacks-16 ohms each
2 x 12 inch Jensen Alnico blackbirds-8 ohms each

Marshall plexi 50 and 100 watt heads both with 2 speaker outputs and ohms adjustment for 4,8,16-

Want to include the above speakers for 4 x 12 cab

Can we include the speakers above even though they are of different ohms and if so what method to use for wiring them up, do we use the push/pull method or what??

Or do we need to have 2 input terminals driving each set separately and if so, then what ohms setting do we use on the amp???

Awaiting your expertise, cheers Mick from OZ!!!


----------



## Billyk

I got a MB30 and want to hookup a 8ohm 10inch speaker cab.do I understand it right if I wire in serial the load on the amp is 16 ohm. That is better than parallel which would be 4ohm load that would be too taxing on the amp. Do I got that right? Or am I smokin crack? Lol seriously though I would like to add this little cab if I could.


----------



## adayme728

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----------



## SmokeyDopey

adayme728 said:


> Microsoft UK executive said today, Microsoft is not ready to join the tablet PC market which is currently in full swing. In fact, Microsoft is the first manufacturers introducing modern “Tablet PC” concept on mobile devices. Windows XP has a standalone version of Tablet PC decade ago, but because it is too far ahead, there was no vendor responsed and was not so easy to use, then gradually Die as a secondary application of the system.... Read more hot news on tracehotnews.com.


----------



## meto

Wery important for me, 
i have the JVM215c, must know which socket is the real for the internal speaker. it was plugged in the first 16 ohm socket, (first from the left side,) when i bught it.. thats correct??? 
it has 8 ohm speaker.. 
and how do i connect both, the internal speaker and 1x12 cabinet with 16 ohm eminence speaker

Any one who can help me out, FREE BEERS,PLS HELP


----------



## squireno7

if I have 4 8 and 16 ohm choices on my combo JCM 800 amp and have just the amp speakers pluged in and they are 2 Celestion G12T-75 wired in series which setting do i use?
and if I plug in another 2x12 cabinet wired in series for a total of two 2x12 cabnets (I have 2 output jacks), which setting is correct?


----------



## KurtisAlan

*Re: SPEAKER WIRING - HELP PLEASE!*

I have a general knowledge of speaker set ups and how ohms work with each other when working in twos and fours, but I have a spare speaker, and id like to attempt to make two separate cabs, one 2x12 and one 3x12.

each speaker is the same 8ohm speaker.

ive done some math that suggests if i have an 8ohm 4x12, and link(aka daisy chain) it together with an 8ohm 1x12 via parallel connection, it will then have a net impedance of 4ohms. is this correct?

and if it is, does that mean i can simply split my 4x12 up, and add the extra speaker to one of the halves? So one cab would be 2x12series(8ohm) while the other cab would have 2x12(8ohm) series - paralleled to the 1x12(8ohm)...
it would still in theory be wired exactly the same just connected via daisy chain in two separate casings, as opposed to all in one case.

for example: 
Speaker Wiring = http://i55.tinypic.com/auedu1.jpg
General Amp Setup = http://i51.tinypic.com/4g0pix.jpg

Im considering building this from what I have, but i dont want to assume I'm correct, and end up putting too much stress on my amp and harm it. Im trying to keep the total impedance at 4ohm as thats what my amp is set to.

feel free to email me, reply, whatever. thanks in advance!


----------



## musicman

I'm looking to wire a 1x12 + piezo horn wedge monitor.

Does anyone know the correct way to do this please ?

I've read both 1x12 & piezo horn directly to the input jack (ie in parallel) with a resitor in series with the piezo horn. Is this correct please ?

If so what value resitor... running a 300w per side amp into 4 wedges = 150w per wedge

1x12 are 300w 8 ohm and Piezo horns are 100w max.

Thanks.


----------



## JohnH

Hi musicman - ive done something similar with my V30 1x12 cab and two piezos. I think my resistor in series with the piezos is 100 ohms, all in series, with that chain in parallel across the main speaker. I also have an extra switchable resistor to tone it down a bit.

The resistor is important to stop unwanted interactions betwen main speaker and piezos, but its value is not critical, so pick it by ear but Id say at least 50 Ohms. I wrote it up here:

GuitarNutz 2 - Speaker cab for electric and acoustic

Also, this site has info on controlling piezos:

PBSONG.COM - PIEZO HORN/TWEETER WIRING DIAGRAMS


----------



## musicman

That's really good info, thanks John.

I'm also a piezo pickup fan, I have Fishman bridges built into my Strat, SG and the Telecaster Partscaster I'm about to start to build.


----------



## dhaywood17

Hi all,

Hopefully a stright forward question.
I'm looking to change the speakers in my 1936 JCM 900 cab to get away from the G12T-75s that seem to be everywhere. I 'm looking to move toward the TSL 2x12 cab which come loaded with a V30 and a Marshall Heritage, both of which I now own. I'm happy with how to select the impedance as they're both 8ohm speakers so I have the choice of 16ohm series or 4ohm parallel ( I'll probably go series). The info I can't find a definitive answer on anywhere is the total watts these can handle when combined. I know that the V30 is 60W and the Marshall Heritage is 70W. From what I've read so far you just add the values together to get a total of 130W. I just want to check before I hook up my AFD100 that this is correct? or should I base this on the lower rated speaker thus giving me a total of 120W?

Thanks in advance.


----------



## dna9656

I have 2 1960 Cabs w/stock Celestions speakers; both for DSL 100. I have 4 greenbacks @ 25 watts on hand I'd like to use in one cab. Each cab has the stereo switch. Can I (and how would I change the wiring) run my 4 greenbacks rated @25 watts each?
Currently I have a DSL 50 and the greenbacks are wired so 2 are paired off in series to create a 50 watt load and both pairs are wired in parallele so the 50 watts load doesn't increase.{Correction: "so there would be equal impedence"}
I'd like to run the green backs on the DSL 100/1960 Cab I just scored. I think I can put each pair in a series to create a 50 watt load and wire both pairs in series to create a 100 watt load; Am I correct so far? 
What about the stereo wiring? Will I have to forego that?
I'm thinking I should get green backs with a higher power rating installed in the other cab and dedicate each cab to a specific amp (50 watt amp vs. the 100 watt amp)/ combination. I'd like the ability to play in stereo using BOTH cabs (at a lower vol. so as not to blow up the DSL 50. Should I just not turn up the green back cab or get 100 watt green backs?
Maybe I should sell the greenbacks and stick with the GM 12s?
Looking for advice, input, and opinions.


----------



## Adwex

dhaywood17 said:


> Hi all,
> 
> Hopefully a stright forward question.
> I'm looking to change the speakers in my 1936 JCM 900 cab to get away from the G12T-75s that seem to be everywhere. I 'm looking to move toward the TSL 2x12 cab which come loaded with a V30 and a Marshall Heritage, both of which I now own. I'm happy with how to select the impedance as they're both 8ohm speakers so I have the choice of 16ohm series or 4ohm parallel ( I'll probably go series). The info I can't find a definitive answer on anywhere is the total watts these can handle when combined. I know that the V30 is 60W and the Marshall Heritage is 70W. From what I've read so far you just add the values together to get a total of 130W. I just want to check before I hook up my AFD100 that this is correct? or should I base this on the lower rated speaker thus giving me a total of 120W?
> 
> Thanks in advance.



Yes, you should base it on the lower rated speaker. A speaker's power "rating" is actually a "maximum power handling capacity". Since the power is evenly divided amongst the speakers, and the "weakest" speaker can handle 60, then the max for the cab is 120.

For the mathematically inclined, the rule is:
Max power for the cab = max power for the "weakest" speaker X the number of speakers

So:
Max power for your cab = 60 X 2 = 120 watts


----------



## Adwex

dna9656 said:


> I have 2 1960 Cabs w/stock Celestions speakers; both for DSL 100. I have 4 greenbacks @ 25 watts on hand I'd like to use in one cab. Each cab has the stereo switch. Can I (and how would I change the wiring) run my 4 greenbacks rated @25 watts each?
> Currently I have a DSL 50 and the greenbacks are wired so 2 are paired off in series to create a 50 watt load and both pairs are wired in parallele so the 50 watts load doesn't increase.
> I'd like to run the green backs on the DSL 100/1960 Cab I just scored. I think I can put each pair in a series to create a 50 watt load and wire both pairs in series to create a 100 watt load; Am I correct so far?
> What about the stereo wiring? Will I have to forego that?
> I'm thinking I should get green backs with a higher power rating installed in the other cab and dedicate each cab to a specific amp (50 watt amp vs. the 100 watt amp)/ combination. I'd like the ability to play in stereo using BOTH cabs (at a lower vol. so as not to blow up the DSL 50. Should I just not turn up the green back cab or get 100 watt green backs?
> Maybe I should sell the greenbacks and stick with the GM 12s?
> Looking for advice, input, and opinions.



Ok, there's a couple of things wrong here. There's no such thing as a "50 watt load". As I mentioned in the post above, the power coming from the amp will be divided evenly amongst the speakers in the cab, regardless of how they are wired. If you connect your DSL 100 to your 1960 cab with ANY speakers in it, each speaker will receive 25 watts (see the rule I wrote above). Actually, the amp will peak significantly higher than 100 watts, so if you load the cab with 25 watt greenbacks, I wouldn't crank it all the way. If you had another 1960 cab, then you'd be safe, with twice as many speakers to absorb the power.

Forget stereo, the DSL is not a stereo amp. Yes you can have two cabs, but it will NOT be stereo. Leave the switch on the cab on Mono, and don't rewire the speakers inside the cab.

Keep in mind that if you use two cabs (of equal impedance, 16 ohms each for example), you need to set the amp for 8 ohms, because the speaker output jacks on the back of the amp are wired in parallel. You must always match the impedance of the amp to the speaker combination you have connected.


----------



## dna9656

Maybe I mis-spoke; maybe I meant to say, "so there would be equal impedence" Question remains did I do it correctly? I realize the DSL is not a stereo amp, but 2 dsl amps fed from a stereo chorus is a stereo set up; is it not? That is my un-stated goal of my original post.
I'd like to play in stereo. I have a DSL 50 and a DSL 100, 1 cab has green backs the other GM12s, what do I do if anything wiring wise. The 1960 w/ stereo switch is bone stock, the other cab is wired as described above. Am I good to go or is there a better way?


----------



## Mangelly

Hey Everybody

Im new to this and joined up because i need help with my JCM 800 1960 Lead Cab. I bought it used and it came with four Celestion speakers. Except two are G12T - 75 and two are G12H- 100. The ones on the bottom (100's) are both working but the two on top (75's_ are not. I took the back of the cab off to look at the wiring and it looks like a mess. Some of the wires look flimsy and like they are the wrong type of wire to even be using. The connections to the speakers are also not great. I would like to re solder all the connections and use the correct wire. Can I get some help on this? What kind of wire do I use? Does anyone have a diagram I can follow for the wiring itself? AND Is it bad two of the speakers are 75 and two are 100? Can that mess my JCM 900 head up? PLEASE help.


----------



## Adwex

dna9656 said:


> Maybe I mis-spoke; maybe I meant to say, "so there would be equal impedence" Question remains did I do it correctly? I realize the DSL is not a stereo amp, but 2 dsl amps fed from a stereo chorus is a stereo set up; is it not? That is my un-stated goal of my original post.
> I'd like to play in stereo. I have a DSL 50 and a DSL 100, 1 cab has green backs the other GM12s, what do I do if anything wiring wise. The 1960 w/ stereo switch is bone stock, the other cab is wired as described above. Am I good to go or is there a better way?



Yes, you are correct, 2 DSLs fed from a stereo chorus is stereo, but it may not sound very good if the amps are set on high gain. The distortion will "distort" the chorus effect. It will sound great with a clean, low gain setting though. The wider apart you place the two cabs, the "bigger" the sound will be. The settings on the chorus will also alter the stereo effect.

I wouldn't change the wiring inside the cabs, just use the greenback cab with the 50. Keep the switch on Mono.


----------



## Adwex

Mangelly said:


> Hey Everybody
> 
> Im new to this and joined up because i need help with my JCM 800 1960 Lead Cab. I bought it used and it came with four Celestion speakers. Except two are G12T - 75 and two are G12H- 100. The ones on the bottom (100's) are both working but the two on top (75's_ are not. I took the back of the cab off to look at the wiring and it looks like a mess. Some of the wires look flimsy and like they are the wrong type of wire to even be using. The connections to the speakers are also not great. I would like to re solder all the connections and use the correct wire. Can I get some help on this? What kind of wire do I use? Does anyone have a diagram I can follow for the wiring itself? AND Is it bad two of the speakers are 75 and two are 100? Can that mess my JCM 900 head up? PLEASE help.



Welcome to the forum.

Your biggest problem is the fact that only two of the speakers are working. This means that the impedance of the cab is not what you think it is. Gotta fix that, because mismatching the impedance between the cab and what the amp is set for is BAD. You run the risk of damaging the amp.

Wire the speakers like this, it's called series/parallel (or parallel/series, depending on how you look at it). Each side pair of speakers are wired in parallel to each other, then the two sides are wired in series.





Get some regular speaker wire from some electronic store or catalog or wherever. I suggest 16 guage. 18 guage will work, but 16 is better. Get the kind that has a stripe or something to indicate which wire is which in the pair so you can get the polarity right.

Actually, pretty much any wire will do, as long as it's a heavy enough guage. Even lamp cord will work fine, or a cheap household extension cord.

The mixed speaker types will not cause any harm to the amp, many people (myself included) mix speakers to get a different sound.
The only thing that has be the same about the speakers is the impedance.


----------



## chuckharmonjr

You would be far better served running a stereo delay in the front end rather than a stereo chorus. Time based spatial effects like a chorus belong in the FX loop. Adam is exactly right on that. Im running a 100 and a 50 in stereo and I split the stereo off at the delay pedal.


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## Beccaio

So...by the pictures here, how is this 1960B cab wired? 

It is estimated from about 1992. 
It reportedly has a bad speaker (upper right.) ETA...multimeter confirms no impedance from upper right speaker.


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## RouteMaster

My amp wants to see 16 ohms and is currently running two 8 ohm speakers in series. 

The question is: It wants 16 ohms, but will also work OK if I connect I connect an 8 ohm load (such as two 16 ohm speakers in parallel instead of the two serial 8 ohms speakers) ?? I suspect this will work, just need some confirmation.


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## mickeydg5

RouteMaster said:


> My amp wants to see 16 ohms and is currently running two 8 ohm speakers in series.
> 
> The question is: It wants 16 ohms, but will also work OK if I connect I connect an 8 ohm load (such as two 16 ohm speakers in parallel instead of the two serial 8 ohms speakers) ?? I suspect this will work, just need some confirmation.


 
What amplifier do you have?


----------



## RouteMaster

JTM60 2x12 combo


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## mickeydg5

RouteMaster said:


> JTM60 2x12 combo


model 622
There are only three choices with that amplifier.
1. internal 16-ohm into internal jack; total impedance 16-ohms
2. internal 16-ohm and extension 16-ohm, one into each jack; total impedance 8-ohms
3. external 8-ohm (only) into external jack; total impedance 8-ohms

You could use two paralleled 16-ohm speakers for total impedance 8-ohm, but that has to be plugged into the extension jack. Nothing else can be used. The internal jack is not used for that circumstance.

Hope that confirms and helps.


----------



## Adwex

RouteMaster said:


> My amp wants to see 16 ohms and is currently running two 8 ohm speakers in series.
> 
> The question is: It wants 16 ohms, but will also work OK if I connect I connect an 8 ohm load (such as two 16 ohm speakers in parallel instead of the two serial 8 ohms speakers) ?? I suspect this will work, just need some confirmation.



Yes it will "work", but you will be running with a mismatch and risk damaging the output transformer.


----------



## RouteMaster

Thanks for the input. I found the manual online and it stated:

Note: The JTM 60 will deliver 60 Watts into
either one or two 16 Ohm speakers, ie. 16 or
8 Ohm total impedance. The unit should not
be driven into a load of less than 8 Ohms.
If you unplug the internal loudspeaker it is
possible to connect a single 8 Ohm cabinet
to the extension Speaker Output only.
However, when the internal speaker is
connected only a 16 Ohm extension cabinet
may be used.

Based on the above, this seems to confirm the idea that you can safely connect two 16 ohm speakers (in parallel) to the extension output (and disconnect the internal output).


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## mickeydg5

You have got it RouteMaster.


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## LSummer

Tried to google about wiring and stuff but didnt found correct answer for this:

I have Marshall B 1960 stereo cabinet, only for stereo connection. Meaning there are two jacks for the 2x12 pair. My question is can I insert a jack like this: http://uraltone.com/kauppa/images/product_images/popup_images/cl1160.GIF to the jackplate and connect the both 2x12 wiring to the jack without doing damage?

Dont have the cab right now here, but I think the wiring is like in this pic:
http://colomar.com/Shavano/4sp_stereo_mono.gif but just without the switch. 

Of course I can buy the original Marshall mono/stereo Jackplate, but the small jack would be just a lot cheaper for few dollars 

Thanks!


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## belgamrood

hi there

i 'm a bit confused about the possibilities of running speakers into a head

i have a jcm 800 kerry king signature 100watt head and two different speakers, an 8ohm and a 16ohm, both 412's
i would like to hook em up both so i have a fullstack

now on the back of the head theres a series of speaker connections, the kinda look grouped
1X 16ohm
1X 8ohm or 2X 16ohm
1X 4ohm or 2X 8ohm






so heres where the confusion starts:
can i simply connect to the 16ohm speaker into the 1X 16ohm connection and the 8ohm speaker into the 1X 8ohm/2X 16ohm connection.will this destroy my amp? or the speakers? or both?

OR

can i hook em up mesaboogie style...they claime 16ohm speaker into 1X 8ohm connection and 8ohm speaker into 1X 4ohm connection is a safe mismatch..but the thing is on a mesa boogie the speaker connections arent grouped like on the back of my kk jcm800. at least not the way the picture it in their booklet

is there any safe way i could connect my setup without destroying anything, since i like to play loud (master volume at least 5.5 or higher)


----------



## Ewlman

belgamrood said:


> hi there
> 
> i 'm a bit confused about the possibilities of running speakers into a head
> 
> i have a jcm 800 kerry king signature 100watt head and two different speakers, an 8ohm and a 16ohm, both 412's
> i would like to hook em up both so i have a fullstack
> 
> now on the back of the head theres a series of speaker connections, the kinda look grouped
> 1X 16ohm
> 1X 8ohm or 2X 16ohm
> 1X 4ohm or 2X 8ohm
> 
> 
> 
> 
> 
> 
> so heres where the confusion starts:
> can i simply connect to the 16ohm speaker into the 1X 16ohm connection and the 8ohm speaker into the 1X 8ohm/2X 16ohm connection.will this destroy my amp? or the speakers? or both?
> 
> OR
> 
> can i hook em up mesaboogie style...they claime 16ohm speaker into 1X 8ohm connection and 8ohm speaker into 1X 4ohm connection is a safe mismatch..but the thing is on a mesa boogie the speaker connections arent grouped like on the back of my kk jcm800. at least not the way the picture it in their booklet
> 
> is there any safe way i could connect my setup without destroying anything, since i like to play loud (master volume at least 5.5 or higher)



I wouldn't say so...

Since the amp has one tap on the output transformer for 16, one for 8 and one for 4 ohm. You can only use *1x16ohm,1x8ohm and 1x4ohm* or if you use the "grouped" parallel connections *2x16ohm* (8ohm total) and *2x8ohm* (4ohm total).

Although I've never had an amp with these kind of outputs I think you're only supposed to use the three groups separate from each other and not in combination.

I've never really been a fan of those 'no impedance selector-amps' because it's very easy for someone less familiar to the system to hook up a cab in every output and blowing it to pieces, although I assume that part is covered in the manual. 

Mixing 1x16ohm cab and 1x8ohm cab will give you a total of 12ohm in parallel so that's not a good idea.


----------



## Ewlman

Okay, guys I hope you with far superior knowledge can give me some advice!

This is what I wanna do: 
I have 1x15" 8ohm cab and 4x10" 8ohm cab. My amp is 8 & 16 ohm out so I want to build a series link out (instead of the more common parallel) from the 4x10" to the input on the 1x15". 

Would this do the trick? Any thoughts?


The speaker in the upper right corner would actually then be the connector/series link out for the 1x15"...


----------



## Ewlman

As I found out earlier today it did not! But as long as DC resistance of speakers behave in the same way as usual resistance when you wire series/parallel connections this slight modification should make it all work as far as the impedance goes.


----------



## Adwex

Ewlman said:


> As I found out earlier today it did not! But as long as DC resistance of speakers behave in the same way as usual resistance when you wire series/parallel connections this slight modification should make it all work as far as the impedance goes.



I don't understand this drawing, but to put the speaker in series with the 4x12, it needs to go in one of the wires leading to the amp.
The wire that says "positive terminal" goes to the negative terminal on the other speaker, then a new wire goes from the positive terminal of the speaker to the positive terminal on the amp. Then the speaker and the 4x12 will be in series, and the resulting impedance will be 16 ohms.


----------



## Ewlman

Yeah, I'm not all that great with drawings... should maybe have used some colors.

What the switch does/supposed to do is basically to let you choose between the 4x10 as a single cab (8ohm) or the 4x10 & the 1x15 (via the series link on the 4x10s cab) by putting the 1x15 in series in the middle of the two parallel sides. Resulting in 16ohms with the both cabs.

Any clearer?


----------



## mickeydg5

I get what you are doing. It will work as you have it or as Adwex explained. It can actually be done without a switch by using a switched jack (normally closed).
I have a question though, what amplifier(s) will you be used in conjunction with the combination of 4x10 and 1x15?
I think it would be better to parallel the cabinets at 4 ohms if possible.


----------



## Ewlman

Hey, Mickey!
We are talking bass guitar cabinets driven by an old super lead clone with 8 and 16 ohms output impedance. The thing is: me and my friend we've had an 8ohm 1x15 cab but wanted to add a 4x10 so we decided to build one ourselves. That's why we wanted 16ohms. The cab is almost finished... only the grill cloth and input panel left. 

Kinda crappy pic but it's something


----------



## mickeydg5

That is cool. I think 4x10,or 2x10's, and 1x15 stacks would be great for guitar. I actually have a cabinet 3x(2-8 & 1-15) at 8 ohms.

Like I mentioned previously, the wiring can be done several ways depending on use of jack(s) and switch. Just mark things to avoid confusion if anyone else plays around with it, so it does not end up with an impedance mismatch.


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## Ewlman

Yeah, marking things is a must! I've actually used the 1x15 (Behringer BB115) together with that same old super lead for some sweet clean guitar tones. It has a really warm and nice sound as long as you keep the harsh tweeter horn switched off. 

Got that 1x15 for 20 euros from a local club in a "need of repair" status. Only thing that had to be done was to super glue the spider back in place 

It'll be very interesting to see what the Celestion BL10s sound like! I've only taken them out for a quick test drive and it seems very promising.


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## Adwex

Ok, now I understand the drawing and the use of the DPDT switch.

Pretty clever, actually.


----------



## Ewlman

Adwex said:


> Ok, now I understand the drawing and the use of the DPDT switch.
> 
> Pretty clever, actually.



Thanks man!
It took some time for me to figure it out but I think it will serve it's purpose well. I will as soon as the cab is finished post a series of pictures showing the building process in the 'Work Bench' part of the forum!


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## Adwex

Just be careful, I'd hate to see that Jubilee get hurt.


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## mickeydg5

Since we are talking jacks and switches with a SuperLead type amplifier, I would suggest ratings of at least 5 amps or more at the contacts.


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## Ewlman

Creepy, you read my mind. I was actually about to ask about what the amp ratings should be. Thanks for the advice though


----------



## Ewlman

Adwex said:


> Just be careful, I'd hate to see that Jubilee get hurt.



Oh, I could never let that happen! 

btw. here's a link to the thread about the building process
http://www.marshallforum.com/showthread.php?p=659276#post659276


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## James Martin

Since you're connecting two cabels, eight ohms every, and therefore the speaker jacks on the rear of the amp square measure wired in parallel, the resultant electrical phenomenon are going to be 1/2 the electrical phenomenon of only 1 cab alone. that is why two cabs, at eight ohms every are going to be constant as one cab at four ohms.


----------



## rocknow

Hi there, I think I'm in the right place for my inquiry.
I want to connect a 6506+ head into one 1960LEADA 4x12 Marshall cab. The head has one ohm selector for 4, 8 and 16 ohm. The cab has a selecor for mono or stereo inputs, you know.

Are the following connections correct:?

1) head swithced at 16 ohm into the 16 ohm channel of 1960 cab (in mono channel mode) , throughout one speaker cable?

2) head swithced at 4 ohm into the 4 ohm channel of 1960 cab (in mono channel mode) , throughout one speaker cable?

What the difference? What the best?

I give a shot of the rear.

I apologize for so much confusion... 

thanx in advance for your helpul reply

rocknow


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## mickeydg5

Hi Rocknow
You can use either setup. Pick the one that sounds best to you. I think there is a minute difference in sound between 4, 8 and 16 ohms but depends on your playing, style, cabinet and actual speakers. you may or may not even sense a difference.


----------



## BobPeabody67

So my Randall has 1X 8 ohm out and 1X 4 ohm out. I have 2X 8 ohm cabinets. Can I just plug both cabinets into both outputs to get a total load of 4 ohms? Or would I just have to deal with a half stack on 8 ohms?


----------



## mickeydg5

BobPeabody67 said:


> So my Randall has 1X 8 ohm out and 1X 4 ohm out. I have 2X 8 ohm cabinets. Can I just plug both cabinets into both outputs to get a total load of 4 ohms? Or would I just have to deal with a half stack on 8 ohms?


 
Hi Bob
That amplifier is only wired up for one jack at each impedance.
To use two 8 ohm cabinets a speaker Y-cable is required and the amplifier's 4 ohm jack would be used.


----------



## BobPeabody67

mickeydg5 said:


> Hi Bob
> That amplifier is only wired up for one jack at each impedance.
> To use two 8 ohm cabinets a speaker Y-cable is required and the amplifier's 4 ohm jack would be used.



Thanks man! What do you suggest for a Y cable?


----------



## mickeydg5

Stuff like this
Pro Cables N Sound Power Y cables, high quality Y cables for speaker cabs and combo amps
or special order from a company like RapcoHorizon

Just make sure to get speaker cables.


----------



## FRED

Right. Most all 4x12 cabinets are series/parallel. The advantage is that the net impedance is equal to the impedance of a single driver. (Just to be pedantic...you must be sure that ALL drivers have the SAME impedance.) If not, it gets more complicated...
But you can get crazy with the concept. Someone (maybe Wizard??) made a 9x12 cabinet (3x3 array), maybe used in a "MONSTERS OF ROCK show. The net impedance of that box would also be the same as a single driver also. Technically, you could also do the same thing with a 4x4 or 5x5 array...
...but I'm not lifting it!!


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## Reginald

btw if you own a 4x12 16ohm speakers cab (each speaker is 16ohms in parallel, so the total ohmmage is 16ohms) running through/by an amp head ,so you should set the head on 16ohm, i know. 
But lets suppose you set the head on 4ohms and start to play it on 10 of volume all the time all the days all the years.. and play and play and play and go on and on and on by lobng term use.
The question is: What will it happen? will a tranny blow up or nothing will happen?


----------



## jbale

I have a masters in physics and your description of wiring makes no sence to me at all, there is a much simpler way to describe your information. I don't know how the others reading your info could possibly understand it.


----------



## ian machin

Hi, desperately need help to what I hope is a very simple question. I have a Laney IRT15H with both 8 and 16 ohm outputs and the following cab. ( see picture) Which output do I connect to on the amp please? I know the cab works and has had the switch removed but not sure how the cab has been wired.
Thanks for any help

Ian


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## Micky

Best way to check is with a meter, you can measure the DC resistance and get a very good idea of exactly how the speaker is wired. Sometimes photos can be deceiving...


----------



## Valvelust

superleadfixer said:


> Also the serie/parallel combination in a 4x12 cab will have a draker sound and a little harcher, if your amp (set up) is too dark one way to help this out would do a Parallel/series connection instead, that will give a little bit cleaner and brighter sound.........



Funny I've been asking this question Parallel/Series or Series/Parallel and most everyone say's it makes no difference. 

Now Im curious!


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## mickeydg5

I am not sure of the intent of the wink in that post.

If using four of the same model speakers they will share equal power dissipation in either setup. It should sound the same.


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## whatknot

Posted some inside cab (1965A) images, and would like to have somebody who knows WTF is going on to tell me what I actually have going on here. Just picked up the cab. Somebody has installed a 1960 mono/stereo switch. I don't want to plug this into my Jube without knowing WTF is going on.

Thanks in advance

Pics here:
About Tal Willis


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## mickeydg5

If that is a normal MONO/STEREO jack plate then be careful. It is wired with four 8 ohm speakers which would give either 8 or 2 ohms in the MONO setting or 4 ohms each side in the STEREO setting.

DO NOT USE THE 2 OHM MONO SETTING! Most amplifiers have a minimum of 4 ohms impedance on the output.

Again be careful. Is the jack plate marked as such with the speakers that are loaded?


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## Ken

That wiring is nuts with 8 ohm speakers! As Mickey said, if they're 8 ohm speakers you will fry anything but a PA system on the mono setting because all 4 will yield a 2 ohm load. 

I assume you want to use all 4 speakers, so wire each pair in series (16 ohms a side), then both pairs to an output jack (parallel) which would give you 8 ohms with all 4 speakers being used. Just be sure all 4 are in phase. I would bypass the switch completely!

Ken


----------



## whatknot

Ken said:


> That wiring is nuts with 8 ohm speakers! As Mickey said, if they're 8 ohm speakers you will fry anything but a PA system on the mono setting because all 4 will yield a 2 ohm load.
> 
> I assume you want to use all 4 speakers, so wire each pair in series (16 ohms a side), then both pairs to an output jack (parallel) which would give you 8 ohms with all 4 speakers being used. Just be sure all 4 are in phase. I would bypass the switch completely!
> 
> Ken



Thanks guys, I knew something looks screwy. I sure am glad I didn't plug it in! Many thanks!


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## Stu74

Hi Im new to the forum. I hope im posting this in the correct place.

Im currently in the middle of building a 2x12 cab to plug into my jcm 2000 tsl 601. Ive been given two 8 ohm speakers that should work out good if I wire them to make a 16 ohm cab. Am I correct thinking that I can use this cab along with the internal 16 ohm speaker in my amp if I set the amp to 8 ohms? 

Im sorry if this has been asked a zillion times before. I just want to be 100% sure before I plug this thing in to my pride and joy.


----------



## mickeydg5

Hello Stu74 and welcome.

This is as good a place as any for posting it.

As long as your internal speaker is 16 ohm, your cabinet setup as 16 ohms and both are connected then you are good to go with the amplifier output impedance set for 8 ohms impedance.


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## Stu74

Thank Mickeydg5 The 2 speakers that im putting in the cab are pretty old and the print that says 8 ohm is very faded so to make doubly sure I checked them with a multimeter and got a rough reading fluctuating between 6.9 and 7.2 ohms.
The one in my amp is definitely 16 ohms.

Is there a test I can do with these old speakers to make sure they actually work?


----------



## mickeydg5

Stu74 said:


> Thank Mickeydg5 The 2 speakers that im putting in the cab are pretty old and the print that says 8 ohm is very faded so to make doubly sure I checked them with a multimeter and got a rough reading fluctuating between 6.9 and 7.2 ohms.
> The one in my amp is definitely 16 ohms.
> 
> Is there a test I can do with these old speakers to make sure they actually work?


Yes, hook them up.  I had to say it. 

Testing or checking with a meter is good. You read good measurements.
You can do a battery test. Take a AA or maybe 9V, with jumpers or whatever touch briefly positive to positive and negative to negative to see if the cone moves outward. That is what should happen. It also indicates proper phase.
Visually inspect for loose or torn parts. Push the cone downward softly to check for freeze, binding or rub.
After that it is all about hooking up and listening.


----------



## Stu74

Thanks again im going to give the battery test a go and then just go for it and plug em in and listen how they sound.

I was also trying to figure out a way to wire the cab with 2 inputs.One for 16 ohm and a 4 ohm input.Not sure it can be done.


----------



## mickeydg5

You can wire them both 16 and 4 ohm with shunt type jacks, like the common CLIFF jacks, one jack for series and the other parallel. Or a decent switch could be used to select configuration.

Both jack's impedance would have to be marked well.


----------



## Stu74

nice one. So it can be done! I will look into it. 
As for labelling I will have it clearly marked up which is which so I don't make any silly mistakes.


----------



## Salsg

Is there any difference in sound in wiring a 4x12 series/parallel or parallel/series. How did the old marshall come wired?
I am planning on rewiring my 4x12 and my intent was series at the speakers then parallel at the jacks.


----------



## mickeydg5

There is no difference in sound until a connection goes bad or a speaker blows.

With the two sets of speakers paralleled and then placed in series if one speaker opens the remaining three will still work. This provides minimal mismatch on output stage and power redistribution per speaker.

If the other case is used and one speaker opens then only two speakers remain working. This has the largest mismatch on output stage and most power redistribution per speaker.


----------



## mtm105

I have a 4X12 Ibanez IS412CA Cab.

I ripped out the speakers and replaced two at a time. I was OK.

Then, I ripped out the backboard and cut out middle 1/3.

But, I forgot how the wiring goes. It's complex because it has both 4 and 16 Ohm feed. I believe I've done transformer damage with it. Not any more.


----------



## Jupa

I have a Marshall 1961B cab, I believe it currently has two Celestion 75's in parallel wiring in it. I want to replace the 75's(16 ohms each I'm guessing since it's an 8 ohm cab) with a CL80 and V30 (both 8 ohm speakers). I want to change the wiring scheme from parallel to series so that I can plug both my 1959 (has 4, 8, and 16 ohm selectable option) and SL5 (only has 8 ohm and 16 ohm inputs) into the cabinet, this way I'd be running both amps at 16 ohms.

Is this wiring diagram correct for what I'm trying to do?
http://www.avatarspeakers.com/pictures/wirserie2.gif

Has anyone gone from parallel to series, and experienced any negative effects (specifically in tone)?

And lastly, 16 ohms is a safe impedance to run amps at correct? 2 an 32 being when you get into bad territory.


----------



## mickeydg5

Hi Jupa
It seems that 16 ohms is your only choice in that case. There may or may not be a noticeable difference in sound but it is something that can always be adjusted with tone controls.

That diagram is correct for series wiring of two speakers.


----------



## Jupa

mickeydg5 said:


> Hi Jupa
> It seems that 16 ohms is your only choice in that case. There may or may not be a noticeable difference in sound but it is something that can always be adjusted with tone controls.
> 
> That diagram is correct for series wiring of two speakers.



Thanks, whilst doing more research I came across this:

http://www.colomar.com/Shavano/2x12wiring2.gif

This seems to have two more wires than the previous diagram, both going to the V in this diagram, what are those? Are they necessary?


----------



## mickeydg5

Jupa said:


> Thanks, whilst doing more research I came across this:
> 
> http://www.colomar.com/Shavano/2x12wiring2.gif
> 
> This seems to have two more wires than the previous diagram, both going to the V in this diagram, what are those? Are they necessary?


It is the same series speaker wiring but has an additional paralleled jack for connecting another speaker cabinet.


----------



## stevebuc

Hi, I'm a new member in need of a bit of help.

I have a 1936 cab with a 1960 switching unit on the back which I'll be using in mono with a JVM410H. The input options are 4Ω and 16Ω which I'm assuming relate to the 1960 cab. Am I right in thinking that with the 1936 cab, I need to connect the 4Ω input to the 1x8Ω output on the amp?


----------



## Micky

stevebuc said:


> Hi, I'm a new member in need of a bit of help.
> 
> I have a 1936 cab with a 1960 switching unit on the back which I'll be using in mono with a JVM410H. The input options are 4Ω and 16Ω which I'm assuming relate to the 1960 cab. Am I right in thinking that with the 1936 cab, I need to connect the 4Ω input to the 1x8Ω output on the amp?



Only if you were using 2 of these cabs.

Best to always match cab to amp, either use the 16-ohm input on the cab with the 16-ohm output on the amp, or the 4-ohm input on the cab with the 4-ohm output on the amp.

Never mismatch, such as what you are suggesting in your OP.


----------



## jack daniels

mickeydg5 said:


> If that is a normal MONO/STEREO jack plate then be careful. It is wired with four 8 ohm speakers which would give either 8 or 2 ohms in the MONO setting or 4 ohms each side in the STEREO setting.
> 
> DO NOT USE THE 2 OHM MONO SETTING! Most amplifiers have a minimum of 4 ohms impedance on the output.
> 
> Again be careful. Is the jack plate marked as such with the speakers that are loaded?



Mickey, it's amazing that Fender Super Reverbs run at 2 Ohms which is almost a direct short (stated by many techs). What was Fender thinking?


----------



## Micky

jack daniels said:


> Mickey, it's amazing that Fender Super Reverbs run at 2 Ohms which is almost a direct short (stated by many techs). What was Fender thinking?



Fender was thinking "If we use a decent OT, the amp should be able to handle just about ANY load a user might connect...'


----------



## jack daniels

Micky said:


> Fender was thinking "If we use a decent OT, the amp should be able to handle just about ANY load a user might connect...'



Schumacher?


----------



## mickeydg5

Fender was thinking like any decent amplifier manufacturer.
Amplifier - four 8 ohm speakers in parallel - 2 ohm secondary. Awesome.

A two ohm secondary impedance is no closer to a short or not much closer to a short than 4, 8 or 16 ohms. We are dealing with AC signal voltage, impedance and speakers.

If any technicians state a 2 ohm output is basically a short with the designed load then I would not bother with their rants.


----------



## mtm105

mtm105 said:


> I have a 4X12 Ibanez IS412CA Cab.
> 
> I ripped out the speakers and replaced two at a time. I was OK.
> 
> Then, I ripped out the backboard and cut out middle 1/3.
> 
> But, I forgot how the wiring goes. It's complex because it has both 4 and 16 Ohm feed.



SHOUT OUT!!! ANY HELP WITH THIS MATTER. PLEASE!!!

I may take it to boutique Amp builder, anyhow. But I'd like to see if I can fix myself.

Both 4 and 16 Ohm feed(s) into four 16 Ohm speakers.


----------



## Micky

Do you need both inputs?


----------



## sellen

American Viking said:


> NO.
> 
> If you only have one cabinet, it's
> 16 amp out to 16 cab in
> or
> 8 amp out to 8 cab in
> or
> 4 amp out to 4 cab in
> 
> The back of the 1960 cab is clearly marked on the right input, MONO 16ohms. Have the switch set to MONO also. Mismatching the impedance will severely damage your amp.
> Even safely running the amplifier at 4ohms from the amp to 4ohms on the cab runs your amp harder and stresses it out for no reason. There is no auditory benefits for running low impedance. Stay at 16ohms and keep your amp happy.


I thought the 4 ohm input and MONO was the right way.
So putting the switch to MONO, set my amp to 16 OHM and put the jack in the 16 ohm input on the cabinet will drive all the speakers in the cab? For me this is a bit confusing as i uesd to 2*12 cabinets. Those are 8 ohm, if you put two together 4ohm. So i don't see the logic.
A pick of how it's look on the back


----------



## Micky

Yes. You are correct.
Measure it with a meter to be sure.


----------



## sellen

You mean i'm right about putting it on Mono and put the jack in the 16 ohm input and set the amp on 16?
I have a meter, tested it on my DSL 401 combo. Took out the speaker jack from amp, And tested with the meter. It seems that it reads about 13,5 ohm, was a bit up an down. So is this the right way to do it and would 13-14 ohm be good 
Thanx for the reply and sorry for the noob questions


----------



## Micky

Yes, you will be ok!


----------



## sellen

Thanx man
Can't wait to do some testing tomorrow


----------



## Gazza J

Hi - I'm new to this forum and hope I'm posting in the right place. Apologies as well if this type of question has already been answered elsewhere...

I have a Laney Chromozone amp that I would like to run into my 1960 Lead 4x12 cab for live work. The cab has the mono/stereo switching, and the amp also has the option to switch between 4 and 8 ohm output modes (pics below).

Amp manual states to use the 8 ohm setting when connected only to the internal speakers (2 x 10") and to switch to 4 ohms when connecting an 8 ohm extension cabinet in addition to the internal.

Both are as stock and unmodified. What's the best way to connect them?

Thanks, G


----------



## mickeydg5

Hello Gazza
It is never a bad idea to ask anything technical when in question.

With those two speaker setups you will have only three choices.
1. run the two 10" internal only at 8 ohms having the amplifier set for 8 ohms
2. run the 4x12 cabinet only at 4 ohms/mono setting having the amplifier set for 4 ohms
3. run the two 10" internal speakers along with two speakers (of the 4x12) using just the right (or just the left) jack at 8 ohms/stereo setup having the amplifier set for 4 ohms

Pick whatever sounds best for the occasion.


----------



## Gazza J

mickeydg5 said:


> Hello Gazza
> It is never a bad idea to ask anything technical when in question.
> 
> With those two speaker setups you will have only three choices.
> 1. run the two 10" internal only at 8 ohms having the amplifier set for 8 ohms
> 2. run the 4x12 cabinet only at 4 ohms/mono setting having the amplifier set for 4 ohms
> 3. run the two 10" internal speakers along with two speakers (of the 4x12) using just the right (or just the left) jack at 8 ohms/stereo setup having the amplifier set for 4 ohms
> 
> Pick whatever sounds best for the occasion.



Cheers mickeydg5, I'll give it a go and let you know what sort of sounds I get out of it!


----------



## Masteresgt

Gazza J said:


> Hi - I'm new to this forum and hope I'm posting in the right place. Apologies as well if this type of question has already been answered elsewhere...
> 
> I have a Laney Chromozone amp that I would like to run into my 1960 Lead 4x12 cab for live work. The cab has the mono/stereo switching, and the amp also has the option to switch between 4 and 8 ohm output modes (pics below).
> 
> Amp manual states to use the 8 ohm setting when connected only to the internal speakers (2 x 10") and to switch to 4 ohms when connecting an 8 ohm extension cabinet in addition to the internal.
> 
> Both are as stock and unmodified. What's the best way to connect them?
> 
> Thanks, G


 
Better to use External cab 1960 only (unplug the internal speaker) and set to 4 ohm.

Or, your can get a Mesa Rectifier Cab (8 ohm) and use internal speaker with 4 ohm setting.


----------



## Gazza J

Masteresgt said:


> Better to use External cab 1960 only (unplug the internal speaker) and set to 4 ohm.



Thanks, Masteresgt, this is probably what I'll do! I really love my amp so don't want to take any risks damaging the OT by mismatching


----------



## Gazza J

As a follow up, does anyone know if it's possible (or wise) to run two different amps into a stereo cab at the same time (one on each 8 ohm side)???


----------



## mickeydg5

That is actually why they were designed. But I would only believe if it were with like amplifiers, each powering two speakers in the cabinet.

Others may have or have used different types of amplifiers for this but the matter of phase and frequency cancellation needs to be considered. This can happen since speaker pairs are not separated internally for the STEREO use.

Anyway just try it. Listen for what sounds bad, good or best.


----------



## GIBSON67

How does the Marshall stereo jack achieve 16 ohms...series/parallel or parallel/series?

I know the speakers are wired parallel for each pair, so I assume it's series/parallel, is that correct?


----------



## mickeydg5

The MONO/STEREO switch and jack connections place the internal paralleled speaker pairs in series when using the MONO 16 OHM JACK.


----------



## Swede

complete wiring newbie....How do i wire up a 1x12 cab? I almost assume I cant go wrong?


----------



## mickeydg5

That would be jack positive (for plug tip) to speaker positive and jack negative (for plug sleeve) to speaker negative.


----------



## Swede

Thanks Mickey. Sounds easy enough. Any specific wiring/gauge u recommend?


----------



## JohnH

Its not super critical. I like a wire like you might strip out of the inside of say a 10amp mains flex. Make it long enough for a bit of droop from jack to speaker. If you are soldering direct to the tabs, best to do the work outside of the cab before installing speaker and jack. Tin both parts first, then bring together and melt with some extra solder for a smooth liquid-looking joint.

So, which tab goes to the jack tip snd which to the sleeve? You cant damage anything if you get it wrong, but it should match your combo speaker to be in phase.


----------



## mickeydg5

That would be 18 gauge stranded copper wire I believe. (average 10A mains)

For 100 watt or less wire gauge of 22 is sufficient for inside cabinet. A little larger is fine.
I think I put 16ga in some.


----------



## Swede

mickeydg5 said:


> That would be 18 gauge stranded copper wire I believe. (average 10A mains)
> 
> For 100 watt or less wire gauge of 22 is sufficient for inside cabinet. A little larger is fine.
> I think I put 16ga in some.



Hey Mickey I bought and used cheapie "speaker wire" as it was advertised at the hardware store....24 gauge. Is that too skimpy or does it matter?


----------



## mickeydg5

I would not place more than 50 watts @ 4 ohms on that.

It may be able to handle it but I think of safety and longevity.

It will be ok if used with another speaker on your DSL40C but I do not recommend it.
If you use it as a lone speaker on a 40 or 50 watt amplifier the wire will be maxed.
If that same amplifier is cranked the wire will be out rated.

Load maxed wire builds heat and resistance.

Double it up or get heavier wire.


----------



## Photojazz

I seem to see a recurring theme here. People seem to want to run a sh.. load of cabinets, and figure, hey I just need one amp. WRONG.

If you have 2 8 ohm cabinets, running them both changes the output impedence of the amp to 4 ohms. Running ANY MORE, ANY TIME, will reduce the amp impedance even further. What does this mean? It means your amp will try to handle a load it is NOT designed for, and at best, it will work for a while, then eventually, it overheats and you've blown your amp. Capish?

It takes one heck of a stout amplifier to handle a 2 ohm load. Taking 4 8 ohm cabinets will half the load 4 times. so 8/4/2/1 You wind up with 1 ohm needing to be supported. In the audio realm, you are talking about the finest amplifiers in the world only can handle a 1 ohm load. 

I run Mark Levinson on my audio system at home, the amp is a 336, and weighs 175 pounds. It's designed to handle down to a 2 ohm load for short bursts, 4 ohm load full time. It might even handle a 1 ohm load for short periods, I can't recall. But that kind of muscle is NOT put in guitar amps.

I hope that helps clarify for some people what they are trying to do. The best you can hope for wanting 4 cabinets is the split the line signal out of your guitar, and run it to two separate amps, driving a pair of cabinets each, then you can have a wall of sound. Protect your ears-

My qualifications are 35 years of audio experience, over 10 years running an audio video forum (htguide.com/forum) and 10 years running an audio video cable business where I manufactured A/V cables. Yes, I can build my own guitar cables, perty ones. haha. But I am not in cable biz at this time. I'm having fun with guitars these days. Life is too short.

Doug


----------



## buickregal400

Hello,, I hope someone can please..I took the factory 4/12 8ohm speakers out of my 4/12mag. I bought 4/12 16 ohm celestion G12T-75 how would I wire them and that shouldn't hurt my amp considering at first the box was 8ohms. And if I wire my 4/12 16 down to 8ohms I should be good right????


----------



## Georgiatec

If you wire your cab the same as the speakers you removed (series/parallel) you will have a 16 ohm cab. Depending what amp you have you just need to use the 16 ohm output instead of the 8 ohm. If your amp is solid state it doesn't matter.
What model amp and cab are you using?.


----------



## BowerR64

Photojazz said:


> I seem to see a recurring theme here. People seem to want to run a sh.. load of cabinets, and figure, hey I just need one amp. WRONG.
> 
> If you have 2 8 ohm cabinets, running them both changes the output impedence of the amp to 4 ohms. Running ANY MORE, ANY TIME, will reduce the amp impedance even further. What does this mean? It means your amp will try to handle a load it is NOT designed for, and at best, it will work for a while, then eventually, it overheats and you've blown your amp. Capish?
> 
> It takes one heck of a stout amplifier to handle a 2 ohm load. Taking 4 8 ohm cabinets will half the load 4 times. so 8/4/2/1 You wind up with 1 ohm needing to be supported. In the audio realm, you are talking about the finest amplifiers in the world only can handle a 1 ohm load.
> 
> I run Mark Levinson on my audio system at home, the amp is a 336, and weighs 175 pounds. It's designed to handle down to a 2 ohm load for short bursts, 4 ohm load full time. It might even handle a 1 ohm load for short periods, I can't recall. But that kind of muscle is NOT put in guitar amps.
> 
> I hope that helps clarify for some people what they are trying to do. The best you can hope for wanting 4 cabinets is the split the line signal out of your guitar, and run it to two separate amps, driving a pair of cabinets each, then you can have a wall of sound. Protect your ears-
> 
> My qualifications are 35 years of audio experience, over 10 years running an audio video forum (htguide.com/forum) and 10 years running an audio video cable business where I manufactured A/V cables. Yes, I can build my own guitar cables, perty ones. haha. But I am not in cable biz at this time. I'm having fun with guitars these days. Life is too short.
> 
> Doug



Run each stack in paralell, then run both stacks together in series.

why wouldnt that work? 8 ohm ontop 8 ohm = 4 then put the 2 stacks together in series brings them back up to 8.

Wish i had the money to try it. 



mickeydg5 said:


> The MONO/STEREO switch and jack connections place the internal paralleled speaker pairs in series when using the MONO 16 OHM JACK.



Hoe do they wire stereo speakers? like are the left 2 speakrs wired to the left plug and the right 2 to the other plug? or top 2 and bottom 2?

I have a cabinet that has 2 closed back at the bottom and 2 open at the top and i always wonderd how it was wired.


----------



## mickeydg5

BowerR64 said:


> Hoe do they wire stereo speakers? like are the left 2 speakrs wired to the left plug and the right 2 to the other plug? or top 2 and bottom 2?
> 
> I have a cabinet that has 2 closed back at the bottom and 2 open at the top and i always wonderd how it was wired.


 It can be done either way unless an internal divider is incorporated.
Two speakers are setup and wired to each jack.


----------



## Shawn721

Hey everyone,
I'm new to this forum and have a couple of questions. 
I recently got a pretty good deal on a 1960V cab loaded with greenbacks. They guy I bought it from wired it for 4 Ohms only. What is the significance of doing that? WOuld it be better to wire it back to 16 Ohms? I am currently using a valvestate vs100 head and it really doesnt sound good at all. Way too much bottom end. I plan to get a TSL or 6100 or vintage modern but its what I have now. 
Any thoiughts?

Thanks,
Shawn


----------



## mickeydg5

Your best bet for the VS100 is 4 ohm setup for most power output.

Too bad the 1960V did not have the Vintage speakers. Those are nice. A lot of people like the greenbacks though.

If you get a tube amplifier and want to have additional cabinets it may be best to have a cabinet at either 16 or 8 ohms. Two cabinets connected (parallel) would be half ohms of each.

Does it have the MONO/STEREO jack plate?


----------



## Alcs760

Hi,
I've been running a Rocktron Velocity 300 power amp through a 212 cab (8ohms mono/16ohms stereo). Now I'm getting a 1960A cab (8ohms stereo/4 or 16ohms mono) for cheap and want to use both simultaneously. How should I hook them up? The Velocity is 150W stereo/300W mono with a minimum impedance of 4 and 8ohms respectively. The total load of the two cabs is what's confusing me. Does the impedance in one channel of the amp affect the impedance in the other one when running the Velocity in stereo?


----------



## HOT TUBES 70

Just thought i would post a link to some good wiring diagrams for those who might be interested etc etc ... 

Jumbo Sunshade - Speaker Wiring Diagrams


----------



## HOT TUBES 70

Alcs760 said:


> Hi,
> I've been running a Rocktron Velocity 300 power amp through a 212 cab (8ohms mono/16ohms stereo). Now I'm getting a 1960A cab (8ohms stereo/4 or 16ohms mono) for cheap and want to use both simultaneously. How should I hook them up? The Velocity is 150W stereo/300W mono with a minimum impedance of 4 and 8ohms respectively. The total load of the two cabs is what's confusing me. Does the impedance in one channel of the amp affect the impedance in the other one when running the Velocity in stereo?



I think i would repost this question in the " Workbench " area ....
This forum is full of smart guys !!!


My thought would be to rewire the 1960 to 4 or 8 ohms if possible .
This way your power amp would be driving the same loads on both channels at the same time , but again i'm no expert !


----------



## mickeydg5

Answered Alcs760 post in the workbench.


----------



## fraserr

Guys, I don't know if you see this but I wanted to toss it out there.... I rewired a pair of 4 ohm Blackstar 4x12's to 16 ohms... They measure 12 and 13. Ohms I thought that was weird so I measured my Marshall's and they are all off by a few ohms as well 8's registering 6 and 5 Ohms a 800 Classic 16 Ohm reading 13.7 - this is done with a dedicated testing jack and a Fluke calibrated scope-meter so it's accurate as I use 1% MOS resistors for reference, I cleaned the jacks, the cables are all 12 ga. short as-can-be pro quality so that and going straight to the cab makes no difference- I assume it's the speaker windings --- Anyone else experience this? 
All the best, 
Rob


----------



## mickeydg5

fraserr said:


> Guys, I don't know if you see this but I wanted to toss it out there.... I rewired a pair of 4 ohm Blackstar 4x12's to 16 ohms... They measure 12 and 13. Ohms I thought that was weird so I measured my Marshall's and they are all off by a few ohms as well 8's registering 6 and 5 Ohms a 800 Classic 16 Ohm reading 13.7 - this is done with a dedicated testing jack and a Fluke calibrated scope-meter so it's accurate as I use 1% MOS resistors for reference, I cleaned the jacks, the cables are all 12 ga. short as-can-be pro quality so that and going straight to the cab makes no difference- I assume it's the speaker windings --- Anyone else experience this?
> All the best,
> Rob


You are reading a DC resistance value, not impedance.
Most speaker coils will generally read a DCR of about 80% the total value of noted impedance on average but depending on the coil used could read anywhere from maybe 66% to 105% on the stated impedance. That is my observations.


----------



## Georgiatec

^^^^^^ This. Your readings are completely normal.


----------



## fraserr

Thanks for the info on this.... Is what I am seeing congruent with most speakers and assuming I should still run them in the paired 8 ohm power-outs on all my heads (2x16 -2 @8 Ohms) Reason I get concerned is one of the Blackstar's is getting toasty quick... Like 218F measured power amp tubes via a Fluke laser thermometer... My DSL100 is about the same but takes longer to get to that temp.... The cabinet on the Marshall is taller and I can only assume that there is better air-flow through the Marshall's as my SLX 100 does not get even close to that temp... It needs a trip to the tech though as it's cutting out- assuming it's the bridge rectifier as they are problematic on these.... And the crap wave soldering as I have dressed about 20 traces already on cold joints and pure crap work,,,, I digress--- Is this valve temp correct or could my bias be off... This amp has a bit more output than it's partner head (HT100 Stage) Dialed in identical the first hot running head has more volume by a tad... I just don't want a pile of blown heads all over the house.... Thanks again for your input on my question--- Greatly appreciated!!!!!!


----------



## mickeydg5

≅
Yes, two 16 ohm cabinets would each be plugged into the amplifier output sharing a paralleled connection for a total of 8 ohm at the output.

Maybe start a different thread in the appropriate forum about the amplifier, tubes and temperature. The 218°F seems ok.


----------



## Cthulhu

Hey guys, read through this thread but wanted to make sure before I fried something:

I've got an Orange PPC212 with two 16ohm inputs.

Currently, I'm running my Marshall 2203 with one cable from the head's 16ohm out into one of the cabs 16ohm in.

I'm adding a Peavey 6505+ and I want to make sure I hook up both heads to the amp correctly.

Do I run one 8ohm out of the 2203 into one 16ohm in of the cab, and one 8ohm out of the 6505+ into the other 16ohm in of the cab?

I want to make sure I'm not supposed to be using two outs on either head (which doesn't make sense because then I wouldn't have any inputs left on the cab to hook up the 2nd head)...

I'm confused...


----------



## mickeydg5

No sir. That is a mono cabinet. You can only hook up one amplifier at a time. The second cabinet jack is for connecting another cabinet and short speaker cable.


----------



## Cthulhu

mickeydg5 said:


> No sir. That is a mono cabinet. You can only hook up one amplifier at a time. The second cabinet jack is for connecting another cabinet and short speaker cable.



Whew, thanks for the reply! So the cab has to have a mono/stereo switch to be able to hook up two amps to it? 

Looks like a second cab is in my future! Hmm, now which one? A 1960A or B perhaps?


----------



## Cthulhu

mickeydg5 said:


> No sir. That is a mono cabinet. You can only hook up one amplifier at a time. The second cabinet jack is for connecting another cabinet and short speaker cable.



What if I plug each amp head's 16ohm out (single cable) to each of the two 16ohm inputs of the cab and just turn on one amp at a time? Will that work, or will the cab notice the other amp head load that is plugged in but turned off and mess some stuff up?


----------



## mickeydg5

That is not a good idea either.
Just use them as intended and according to manual instruction.


----------



## tschrama

OMG.... 10 pages about speaker wiring? And they made it a sticky too?


----------



## EndGame00

Would using two different wire gauges hurt my amp? I'm replacing the wiring on my 2x12 but I got two braided wires that are 16 and 14 awg..would it matter or do I need to get a match gauge?


----------



## mickeydg5

If the speakers are in parallel then do 14 to the first from the jack and then use the 16 for the second.

If in series I would use all the same size but honestly at those gauges and lengths do not worry and all will sound the same anyway.


----------



## EndGame00

Double post.


----------



## EndGame00

It has a mono-stereo switch (I think they are wired series/parallel and they are circuit board), however the the wire connection to the input jack was gooped up with silicon gel so I decided to cut a strip from the stock wire and added the desired length instead of replacing the entire wire altogether...works for me.


----------



## jackie_lee

Hi guys, i need your help.
I have this gear:
1 marshall jmp 1980 100 w head, with 2 output, switch for 4-8-16-ohm
1 heil dunlop talk box (8ohm)
1 marshall 1960A cabinet 4x12, with 4 x celestion g12t75 16 ohm, paralel wiring (i think), with mono (4-16 ohm) n stereo (8-8 ohm) switch
1 marshall 1960B cabinet 4x12, with 4 x celestion vintage 30, 16 ohm, paralel wiring (i think), with mono (4-16 ohm) n stereo (8-8 ohm) switch

so...how i must to link all this things...i know the normal link between head + 2 cabinets, but, with the talk box? what i must to do?
i need to change the wiring of the cabinets?

Thanks alot


----------



## mickeydg5

The box will take half of your wattage.

The only way to hook that up would be to parallel the two 16 ohm cabinets from one amplifier output jack and connect the box to the other for a total of 4 ohm impedance out of the amplifier.


----------



## Scott Howard

I have avt50 w/4 ohm minimum can connect 2 8 ohm cabs to this head?


----------



## BowerR64

Can i wire a 1936 2X12 cabinet so that i can use it in stereo and mono? but the mono be in series?

My 4X12 is a 16 ohm cab and the 2 drivers in the 1936 are both 8 so i wired it in series so that i could run both cabs together 16 each.

I got a Mustang V and i want to use it in stereo threw the 1936 but still be able to use it with my 4X12 at 16 ohms.


----------



## mickeydg5

Scott Howard said:


> I have avt50 w/4 ohm minimum can connect 2 8 ohm cabs to this head?


Two 8 ohm cabinets which are parallel will equal a total of 4 ohms, so yes.


----------



## mickeydg5

BowerR64 said:


> Can i wire a 1936 2X12 cabinet so that i can use it in stereo and mono? but the mono be in series?
> 
> My 4X12 is a 16 ohm cab and the 2 drivers in the 1936 are both 8 so i wired it in series so that i could run both cabs together 16 each.
> 
> I got a Mustang V and i want to use it in stereo threw the 1936 but still be able to use it with my 4X12 at 16 ohms.


I do not see how without some sort of manual switching.


----------



## BowerR64

Well i have a couple of those 6 pin jacks, they are like switching jacks. If you plug a male jack into these jacks the 3 pins on one side disconnect i figured i could some how wire it using those little tab switches.

4,5,6 are connected when the male jack is plugged in. 1.2.3 are connected to 4.5.6 when nothing is connected. But also pins 5 and 6 short together when a jack is plugged in i think for like switching a battery on in a pedal or something.


----------



## mickeydg5

That is why I said "manual switching" above.


----------



## BowerR64

ok, well i have 2 of those but i cant figure out how to wire it so that it has 2 8s in stereo then a 16 in mono. They are 2 8 ohm V30s

Can you connect the dots for me? lol


----------



## mickeydg5

When I say a manual switch that is referencing a toggle type switch.
It cannot be done with shunt jacks; parallel configurations yes, but not series for what you want.


----------



## BowerR64

What if i used 3 jacks?

Left jack directly to the left speaker, right directly to the right speaker and the 3rd one connecting both in series?


----------



## mickeydg5

Actually with three jacks it is possible. Two jacks would separate the two speakers which could also be paralleled to the source. The third jack can be configured to series the other two jacks/speakers.

Can you figure it out or do you need a diagram?


----------



## BowerR64

Not sure how i would break the connection between the 2 speakers when im using it in stereo.

I wouldnt want the line that ties the 2 together.


----------



## mickeydg5

The third jack breaks the connections between speakers allowing stereo from two amplifiers or mono paralleled from one amplifier's two output jacks with two speaker cables.
When in mono series connection only one speaker cable is needed.


----------



## BowerR64

This is what i was thinking, but im sure im not using the jacks like i could?


----------



## mickeydg5

Your blue wire up there would short out the right speaker when both jacks for stereo are in use.


Try this.


----------



## BowerR64

If i plug a jack into the mono plug that opens the connection to pin 3, so when running in mono where is the - lead?

4,5, and 6 brak connections to 1,2 and 3 when a plug is inserted.


----------



## mickeydg5

I fixed it. The blue line was drawn to the wrong lug.


----------



## BowerR64

Thanks man!

Do you see how lugs 5 and 6 are like a switch? when nothing is plugged into them 5 connects to 2 and 6 connects to 3, but when a mono plug is in the long ground part of the 1/4" jack connects 5 and 6 together i was trying to use that some how but i couldnt figure it out.


----------



## mickeydg5

5 and 2 are mainly for TRS plugs, not that you cannot use them for certain circumstances. However with your TS plugs they are not practical.
Also shunts on a jack are dependent on connection(s) whereas a toggle is set by position and connection(s). I do not know if I can explain in it a better or simpler way.


----------



## BowerR64

This is how i did it, tell me if you see any problems i may have.


----------



## mickeydg5

From what I can see it looks correct.
Measure resistance using your speaker cable. Each STEREO jack should indicate something below 8 ohms (7 or so) and the MONO-SERIES in the center should indicate something below 16 ohms (the two added together).


----------



## Scumback Speakers

If anyone needs a wiring diagram for cabs that's easy to read, I have them on my site here: http://www.scumbackspeakers.com/wire.html

There are also links there to download a bigger PDF file to zoom in on if you need it. I don't have a 1x12 wiring there since it's just a straight connection to the speaker.

I do show the two different ways that Marshall cabs have been wired. Series/Parallel is the most common I've seen, and Parallel/Series is there as well. I find the S/P setup is a bit more laid back and bluesy sounding (60/70's tones) and the P/S wiring has a bit more immediate feel/response. You can always try both and listen to what works best for you.


----------



## BowerR64

Will this work?

I have a 1936 with 2X8ohm V30s, and a 4X12 with 4-16 ohm G12T75s i kinda want a pair of the G12T75s up at ear level where the V30s are now. Ide like to move the V30s down at the bottom of the 4X12 but still run them like i was running them in the 2X12 (in series)

If i only run both cabs together couldnt i get away with mixing a pair of 16ohm and a pair of 8ohm in the same cab?

Would i run the V30s at the bottom of the 4X12 in series or just run them the same way as all 4-16 ohms series/parallel?


----------



## mickeydg5

I would say put the 2x12 on the bottom or off to the side on a titled stand.


----------



## BowerR64

I think im going to just put the V30s at the bottom of the 4X12 and put them on their own jack wired in series. (16 ohm total)

Then ill put one pair of G12T75s on the top slant part of the 1960a in series and the second set in series in the 1936 and run those 4 together in parallel. 16ohm total

I like the sound of the G12T75s better so i want em up where i can hear em and the V30s down at the bottom of the 1960a where you cant really hear em anyway.

I doubt i could trade my V30s for a pair of 8ohm G12T75s

I dont like the 1960 on the 1936 it fits so much better the other way around.


----------



## BowerR64

This is how i got it all to work. Since i got the 4X12 cheap off CL it was all butchered up when i got it with all the ports in the back. I recovered the front and put speakers in it and i kinda liked it so i left it. The 1936 is sealed and running them together for some reason made the whole setup sound thin. I found if both cabinets are either closed or open they work together but if one is open and one is closed they seem to cancel each other out dont ask me why but they did.

Like i said in the previous post the V30's at 100db were way to loud couldn't hear the speakers in the 4X12 at all (97db G12T-75s). So i decided to put the V30s in the bottom of the 4X12 and split the 4 G12T-75s into pairs. One pair in the 1936 and one pair in the top of the 1960a. It almost sounds like a subwoofer/Satellite setup. since the V30s are down low i don't really hear the upper frequencies from them since they arn't at ear level or pointed at the ear but i hear the bass which is slightly louder then the G12T75s Its like a wide stereo sort of sound but vertical really weird but i like it and it works.

The V30's are on their own jack at 16 ohms (in series) directly to the amp, then the 2 pair of G12T-75's are on their own jack (one set in the 1936 cab) each pair wired parallel. Then wired both sets together in series to create 16 ohms to the amp. The amp is set to 8 ohms

I like this setup so ill cut a new back for the 1960a and use a 2 jack plate and run one to the bottom and one tot he top set but it should look like a newer 1960a plate with the stereo/mono switch plate.


----------



## gary moore

DSL 40C combo.Can I run another 16 ohm speaker with the original together?
Thanks


----------



## mickeydg5

gary moore said:


> DSL 40C combo.Can I run another 16 ohm speaker with the original together?
> Thanks


If the a 16 ohm speaker is loaded then another 16 ohm cabinet can be utilized along with it. Just plug them into the two 8 ohm amplifier speaker jacks; two 16 in parallel = 8 ohm total impedance.


----------



## texhex

Hello, I have a DSL100H and a MX412A. I found a 4x12 on CL with G12K-85 speakers for $100. I'd like to run both of these from my DSL100H and am worried about the wiring in both cabinets being compatible with each other.

All the speakers are 16 Ohm. The DSL100H has a single 16 Ohm and two 8 Ohm outputs. I'm worried that the wiring in the G12K-85 cabinet is not compatible with the MX412A.

The G12K-85 cabinet has two inputs and I've already tested connecting the MX412A to the G12K-85 cabinet by plugging the amp into one of the G12K-85 cab inputs and then plugging the MX412A into the other input on the G12K-85 cab. Both cabinets worked but I'm worried about impedance and damaging my amp.

I was using the 16 Ohm output from my amp but from reading some posts I think I should be using the 8 Ohm output from the amp, unless the speaker cabinets are wired in a way that would make that incorrect or incompatible. 

Can someone take a look at the attached pictures and let me know if these two cabinets will work together? When I was testing it they sounded great together, I just don't want to damage my amp. Thanks!

MX412A wiring:





G12K-85 wiring:






Input on the G12K-85 cab:


----------



## texhex

So it looks like the G12K-85 cab is wired Parallel-Series and the MX412A is wired Series-Parallel according to these diagrams.
http://www.hugeracksinc.com/forum/viewtopic.php?t=61163

I'm not sure if that matters when plugging the G12K-85 cab into th MX412A cab but I'm going to run my amp at 8 Ohms in any case.


----------



## mickeydg5

texhex
They both appear to be wired as you said and at 16 ohm impedance each.
So use the two 8 ohm impedance output jacks on the back of the DSL100H.


----------



## damuncha

Hello

I was wondering if I can get some help please confirming a couple of things. 

I have an angled 4x12 cabinet labeled JCM 800 lead series. There are two inputs on the back. Is this normal? 

If so, how would the two inputs be used? Surely not to two amps?

This is how the speaker jacks are wired



Secondly, from looking at the wiring it looks to be wired Parallel/Series. Can you confirm this please? It's making my head spin!

Here's my hand drawn diagram:


----------



## mickeydg5

The cabinet has a single cup/jack in that case. It was modified.

That is Series-Parallel. But each set of two is placed in series and then the two are paralleled at the jack.

It was probably done to run a speaker cable from that cabinet to the next for paralleling cabinets or to run two speaker cables from an amplifier's output jacks to the two jacks in the cabinet for better cable/connection power handling to a single cabinet.


----------



## damuncha

Thanks for that. So for two cables going from the amp to the cab I'm assuming that you would keep the amp set to 16ohms. The speakers are all 16ohm. 

I was doing a bit more searching online last night and found this diagram:






That to me seems to most closely match what I have in the cab. 

This is their diagram for series parallel:





I just wanted to double check if it's Series/parallel or parallel/series.

Sorry for the dumb questions. I usually just plug in and go but I wanted to try and learn more about my kit.


----------



## mickeydg5

Ha, ha. It just looks different somehow to you.

Actually and I hate to crap on a parade but both of those Scumback diagrams are actually series sets paralleled at the jack or source. You have to look closely. They are just drawn differently. The electrical connections of the two diagrams provide the same situation.

I know Scumback is a sponsor here, the guy is a member and lots of people like Scumbacks. I have seen these diagrams posted here before and no one ever commented on them or even noticed I guess that I remember. So I am commenting.

For information: in electronics there are series, parallel and series-parallel circuits. There is nothing called parallel-series. There are however deviants of series-parallel which include strings, branches and banks or whatever and so on.

So paralleled speaker sets placed in series at the jack would still be a series-parallel circuit with two banks of paralleled resistance place in series with the source. (#1 below) That is not happening in that first diagram.

Likewise as mentioned earlier, series speaker sets placed in parallel at the jack would still be series-parallel circuit with two branches/strings of series resistance placed in parallel with the source. (#2 below)

I found this on the net and think this may look simpler.


----------



## danfrank

mickeydg5 said:


> I found this on the net and think this may look simpler.
> View attachment 42181



Which one is supposed to sound better? #2? I know a lot of people think one is better than the other, sound wise...


----------



## Scumback Speakers

mickeydg5: I hate to rain on your parade, but Celestion thinks so. Those diagrams are just updated, easier to read versions of the diagrams they have on their site, and those are the wiring diagram names they use. 

I'm not saying Celestion knows everything, but since I provide these diagrams to help people rewire their old (pre stereo switch) cabs, I used the naming convention that Celestion used so that people knew what they had. 

If it's wrong, well, ok...but it's not my doing that it's named that way, I was just duplicating their wiring names for simplicity for others who know them as those names.

Not taking it personally, so no harm, no foul, but let's give credit where it's due, ok? LOL


----------



## Scumback Speakers

danfrank said:


> Which one is supposed to sound better? #2? I know a lot of people think one is better than the other, sound wise...


Using the Celestion diagram name, the parallel/series wiring has more midrange attack/bite, while the series/parallel wiring is more laid back and vintage sounding. Electrically they're the same thing, soundwise, they are different.


----------



## Scumback Speakers

The page has changed, but here's the Celestion wiring link: 
http://celestion.com/speakerworld/guitartech/7/39/Speaker_Wiring_Configurations/


----------



## Dogs of Doom

The red boxes represent a series. In the 1st drawing, you can see that there are 2 series connections side-by-side. In the 2nd the 2 series are paired top/bottom...

The +, from the top left speaker, runs to bottom left +, which makes the parallel from the jack. The -, from top right goes to - bottom right...


----------



## danfrank

OK, so which one has more midrange attack/bite and which one is more vintage sounding, referring to the diagram MD5 provided in post #324. Sorry but the Celestion page doesn't work for me...


----------



## mickeydg5

I do not think one will sound better than the other if using 4 of the same speakers. All speakers will get the same basic voltage and current so therefore same power.

A mixed set of speakers in a 4x12 will have more variances.


----------



## danfrank

OK, Thank you. The physics of it would say that both ways should sound the same.


----------



## decoder

Hi

I just bought a 1973 JMP 50 (1989) watt head and Im looking at getting a 2x12 with greenbacks, what Ohm speakers do I need?

Thanks


----------



## mickeydg5

decoder said:


> Hi
> 
> I just bought a 1973 JMP 50 (1989) watt head and Im looking at getting a 2x12 with greenbacks, what Ohm speakers do I need?
> 
> Thanks


You should have a choice of output impedance for 16, 8 and 4 ohms.
With a 2x12 there are generally three options with guitar speakers:
two 16 (or 15) ohm speakers in parallel for 8 ohm output
two 8 ohm speakers in series for 16 ohm output
two 8 ohm speakers in parallel for 4 ohm output


----------



## decoder

mickeydg5 said:


> You should have a choice of output impedance for 16, 8 and 4 ohms.
> With a 2x12 there are generally three options with guitar speakers:
> two 16 (or 15) ohm speakers in parallel for 8 ohm output
> two 8 ohm speakers in series for 16 ohm output
> two 8 ohm speakers in parallel for 4 ohm output




Thanks So either 16 or 8 ohm would be ok. Great.


----------



## decoder

hi. i have bought a 2x12 cab devoid of its speakers. i want to install a single 8ohm creamback ive bought and see how this one speaker sounds in the large cab. there the jack on tge back panel with a pair of cables soldered to it, can i just attach these to the creamback and set my head to 8ohm?

thanks


----------



## decoder

heres how it looks. thanks


----------



## mickeydg5

One 8 ohm speaker connected to the 8 ohm amplifier output is good.

If you have a meter check the resistance at the plug on the other end of the speaker cable once connected to the cabinet jack. It should read somewhere under 8 ohms resistance.


----------



## decoder

thanks. i just wasnt sure if the series/parallel thing happened inside the jack (pre wired so to say) or is something thats done after the jack. i didnt want to attach a single 8 ohm speaker to a jack that was wired for parallel for instance. i kniw nothing about this, as you can see


----------



## mickeydg5

decoder said:


> thanks. i just wasnt sure if the series/parallel thing happened inside the jack (pre wired so to say) or is something thats done after the jack. i didnt want to attach a single 8 ohm speaker to a jack that was wired for parallel for instance. i kniw nothing about this, as you can see


The wiring/power flow make it either series or parallel. With one single coil speaker the only choice is series.


----------



## decoder

mickeydg5 said:


> The wiring/power flow make it either series or parallel. With one single coil speaker the only choice is series.



Thanks.

Yep, I have the single creamback in the 2x12 cab (an empty Framus CS 212 I bought online, used). Sounds really great, the larger cab makes a big difference, I suspect some of the sound comes off the 90% closed back of the cab and out of the hole where the second speaker should be, sounds really big.


----------



## mickeydg5

Yes. You may say that is an extra large untuned port. It does however act like a partial open back cabinet except shooting forward. So now it is a partial open front cabinet.


----------



## Richard Martin

Guv'nor said:


> The most common methods to wire up speakers are Series and Parallel.
> 
> It is also quite common to wire Speakers in a Series/Parallel Combination.
> 
> 
> 
> 
> 
> Single speaker
> 
> Wiring up Speakers correctly to provide the best possible sound, requires some knowledge of Loading, Phase, and Impedance, while understanding Ohms Law will help you to connect your speakers properly.
> 
> *SERIES*
> 
> 
> 
> 
> 
> 
> Adding Speakers in series increases the overall resistance of the circuit.
> 
> Therefore the resistance of each Speaker is added together, For advanced installations with Multiple Speakers, Series Speaker wiring can be used to increase the resistance of the “equivalent” or “overall” resistance that the Amplifier sees. This allows the Amplifier to run cooler and more efficiently.
> 
> Series Circuits are “voltage dividers”, and using Ohms Law, one sees the result as a decrease in amplified voltage audio signal to each Speaker. Since Series Circuits are “voltage dividers” each Speaker sees a percentage of the amplified output from the Amplifier. It is often assumed the Amplifier is producing less output, but it still produces the same output, because each Speaker only gets a percentage of the overall power.
> 
> Formula: Znet = Z1 + Z2 + Z3 + .... + Zn
> 
> _Example:_
> 
> 2 x 4 Ohm Speaker = 4 + 4 = 8 Ohm Load
> 2 x 8 Ohm Speaker = 8 + 8 = 16 Ohm Load
> 
> *PARALLEL*
> 
> 
> 
> 
> 
> 
> Adding Speakers in parallel decreases the overall resistance of the circuit
> 
> Parallel Speaker Wiring combines all Speakers (+) positive Speaker leads together, and all (-) negative Speaker leads together.
> 
> Adding additional Speakers is as easy, however, adding Speakers in Parallel causes the overall resistance of the circuit to drop, as resistance drops, the current must increase according to Ohms Law. So, each time a Speaker with the same resistance is added to the parallel circuit, the current draw on the amp increases. The circuitry of the amp must be able to handle this increase in current at the reduced resistance.
> 
> Formula: Znet = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)
> 
> _Example:_
> 
> 2 X 4 Ohm Speaker = 1 / (1/4 + 1/4 ) = 2 Ohm Load
> 2 x 8 Ohm Speaker = 1 / (1/8 + 1/8 ) = 4 Ohm Load
> _
> Note:_ If more than 2 Speakers are connected in Parallel, so long as they are all the same impedance then the net impedance of the load is equal to the impedance of the one Speaker divided by the total number of Speakers. For Example 3 8 Ohm Speakers in Parallel, the Impedance is 8/3 or 2.667 Ohms.
> 
> *A COMBINATION OF SERIES & PARALLEL*
> 
> 
> 
> 
> 
> 
> In reality this is just two sets of Series Speakers wired in Parallel
> 
> Formula: Znet = Znet1 + Znet2 + ... + Znetn; where Zneti = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)
> 
> _Example:_
> 
> 4 X 8 Ohm Speaker = [1 / (1/8 + 1/8 )] + [1 / (1/8 + 1/8 )] = 4 + 4 = 8 Ohm Load
> 
> *WIRING A FULL STACK*
> 
> The amp usually has two speaker outputs (one for each cab)
> 
> The output jacks are wired in parallel. It means Znet = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)
> 
> Therefore having 2 cabs at 8Ohm the head will see 1 / (1/8 + 1/8 ) = 4 Ohm Load
> 
> Enjoy!


I have a Marshall 1960 lead cabinet, I had to take the back off, the cabinet was not working, it's not very old but I had to resolder, a few of the posts they were REAL lose. Anyone know ware I can buy a replacement for that Jack the one thats got the two inputs and the mono, stereo switch for wattage


----------



## BowerR64

E-bay has them but they arnt cheap.


----------



## BowerR64

mickeydg5 said:


> Ha, ha. It just looks different somehow to you.
> 
> Actually and I hate to crap on a parade but both of those Scumback diagrams are actually series sets paralleled at the jack or source. You have to look closely. They are just drawn differently. The electrical connections of the two diagrams provide the same situation.
> 
> I know Scumback is a sponsor here, the guy is a member and lots of people like Scumbacks. I have seen these diagrams posted here before and no one ever commented on them or even noticed I guess that I remember. So I am commenting.
> 
> For information: in electronics there are series, parallel and series-parallel circuits. There is nothing called parallel-series. There are however deviants of series-parallel which include strings, branches and banks or whatever and so on.
> 
> So paralleled speaker sets placed in series at the jack would still be a series-parallel circuit with two banks of paralleled resistance place in series with the source. (#1 below) That is not happening in that first diagram.
> 
> Likewise as mentioned earlier, series speaker sets placed in parallel at the jack would still be series-parallel circuit with two branches/strings of series resistance placed in parallel with the source. (#2 below)
> 
> I found this on the net and think this may look simpler.
> View attachment 42181



even though they are the same wired or what ever, isnt there a way to wire a 4X12 so that if any of the speakers fail the cabinet will continue to work?

I may be wrong but one of the diagrams looks to be wired so if a speaker fails or burns a coil so its 0 ohms the other 3 will still work, The other looks like its wired so if one burns the cabinet will no longer produce sound?

Again im probably wrong


----------



## mickeydg5

With any four speaker cabinet the other speakers should still continue to work. It just ends up with two different conditions if a speaker does go out depending on the wiring scheme.
The safest bet would probably be the two speaker sets placed in series with each pair paralleled at the cabinet input jack but either scenario would still work.


----------



## Richard Martin

Thanks for your imput, I'm going to order new plate switch for the Marshall 1960 lead cabinet!
I m going to check wiring also order new cabinet cable. Not taking any more chances with blowing
Head! Take care all have great new years!!?


----------



## Richard Martin

mickeydg5 said:


> With any four speaker cabinet the other speakers should still continue to work. It just ends up with two different conditions if a speaker does go out depending on the wiring scheme.
> The safest bet would probably be the two speaker sets placed in series with each pair paralleled at the cabinet input jack but either scenario would still work.





mickeydg5 said:


> With any four speaker cabinet the other speakers should still continue to work. It just ends up with two different conditions if a speaker does go out depending on the wiring scheme.
> The safest bet would probably be the two spea
> ker sets placed in series with each pair paralleled at the cabinet input jack but either scenario would still work.



Hi mickeyd5, I got my replacement JVM 205 h yesterday, I ordered cabinet cable, they sent me a 12 Gage cable! I get no sound from my cabinet, it's not the new head, the cable wouldn't work with my little Marshall mini stack either, I was afraid to use the little cable on my new head! Don't want to buy up a transformer. Got to call Marshall tomorrow and ask what type and Gage cable I should use. I've had real bad luck with buying heads lately, One floor modle JVM 410 h and one JVM205 h brand new, just got the replacement head for the 205h but still got to get my 410h head yet! Sorry I forgot to ask ya, I had someone tell me I shouldn't plug
My JVM'S into to stereo side of my 1960 Marshall lead angle cabinet? I told him I had never herd that you could not use the 16ohm stereo side with one cabinet? I thought it didn't matter as long as I was plugged in to the 16 ohm single Jack on the head.
I never had any problem with any of my Marshall amps in the past. I used a couple of JCM'S 900 DUAL LEAD HEADS I never had any problems with them. Thanks for your help have great new years!!


----------



## mickeydg5

You need a multimeter to check both the cable and the cabinet. The cabinet should be set for 16 ohm mono as well as using the heads 16 ohm output option. The larger gauge of speaker cable does not matter. Larger gauges can handle more amperage and ultimately more power.

You could have a bad speaker cable or the cabinet is not working correctly.


----------



## toadfish

I use the Scan-Speak 130mm MPSS01 flow resistor in the back of closed cabs and I like them! Sort of mini rear porting with a semi open back feel! I tried to upload a picture but it's to large I buy mine from www.speakerbits.com who I have no affiliation with! And like the boy's suggested buy a Multimeter and learn how to use it as it will sort out a shitload of problems checking cabs n cords but I wouldn't go stuffing it in High Voltage amps!


----------



## LRT#1

Ok I have a jcm900 1960a cab. It has the 2 Jack's 4/8 ohm and the 8/16 ohm. In between is a mono stereo switch.

Does this switch mean its wired to run like 2 2x12 cabs?

If I ran stereo could I slave 2 heads together?

If I could slave 2 heads into the one cab.
What would the ohms setting be?


----------



## mickeydg5

The two halves of the 1960 are not separated so I would not run two heads into it. There will be phase issues.

The cabinet can be set to one of three ways:
mono 16 ohms
mono 4 ohms
or dual input at 8 ohms per pair (kind of like two 2x12 but not quite)


----------



## LRT#1

So I would use both outs from head as if it was 2 2x12s stacked? 
And ohms would be set to 8 ohms?
This is if I understand correctly.


----------



## mickeydg5

LRT#1 said:


> So I would use both outs from head as if it was 2 2x12s stacked?
> And ohms would be set to 8 ohms?
> This is if I understand correctly.


If you have one amplifier and on speaker cabinet then you only need one speaker cable.
The cabinet gets set to MONO and either the 16 ohm or the 4 ohm option is used for both cabinet and amplifier.

If you want to run more wattage, slaving a second head, then both heads should be kept in phase and using the same signal for best results. With that setup then two speaker cables are required, one from each amplifier to the cabinet using STEREO option and the individual 8 ohm input connections. It still going to sound mono but with more power and maybe color. Do not overpower the cabinet.


----------



## LRT#1

If I dont slave two heads, but want to run both out puts. Do I switch to stereo and set head to 8ohms out put.
This is what I'm understanding.
If this is correct what will it do to the sound?
Do I need to keep volume down to not push the speakers to hard?


----------



## mickeydg5

Refer back to post #352.

The two amplifier speaker jacks connect to the same output. They are paralleled connections. Both are used when utilizing more than one cabinet for convenience.


----------



## LRT#1

Thanks mickey


----------



## SkyMonkey

Sorry. I can't face trawling through this whole thread to find the answer I need.

I am looking to wire in a speaker cable to a solid state combo (VS65R) to allow connection to a 112 extension cab. The load of the combo is no less that 8 Ohm, so I am installing 16 Ohm speakers in the combo and cab for wiring into parallel, for an 8 Ohm load.
All the diagrams for speaker wiring seem to have disappeared from the start of this sticky thread (at least on my PC), so could someone advise how to do this. 
I am intending to cut an old speaker cable, strip the wires and install spade connectors, then clamp the cable to the combo chassis (open back). The cable will then just plug into the cab below the combo. Cay you advise how to connect this up correctly?

Cheers guys.


----------



## ampmadscientist

SkyMonkey said:


> Sorry. I can't face trawling through this whole thread to find the answer I need.
> 
> I am looking to wire in a speaker cable to a solid state combo (VS65R) to allow connection to a 112 extension cab. The load of the combo is no less that 8 Ohm, so I am installing 16 Ohm speakers in the combo and cab for wiring into parallel, for an 8 Ohm load.
> All the diagrams for speaker wiring seem to have disappeared from the start of this sticky thread (at least on my PC), so could someone advise how to do this.
> I am intending to cut an old speaker cable, strip the wires and install spade connectors, then clamp the cable to the combo chassis (open back). The cable will then just plug into the cab below the combo. Cay you advise how to connect this up correctly?
> 
> Cheers guys.




parallel speaker wiring. 2X 16 ohm speakers in parallel = 8 ohms.


----------



## SkyMonkey

So I would be right to work out which wire of the speaker cable goes to which terminal in the cab speaker. Then connect the cable spades to the second tabs of the corresponding terminals of the combo speaker?

If so, then cheers AMS! 

I will post again soon when I've managed to try it out. Still waiting on a speaker cable delivery.

BTW, how would you expect the combo to sound with only its 16 Ohm speaker connected (louder/quieter/darker), and how safe would that be to run?


----------



## ampmadscientist

SkyMonkey said:


> So I would be right to work out which wire of the speaker cable goes to which terminal in the cab speaker. Then connect the cable spades to the second tabs of the corresponding terminals of the combo speaker?
> 
> If so, then cheers AMS!
> 
> I will post again soon when I've managed to try it out. Still waiting on a speaker cable delivery.
> 
> BTW, how would you expect the combo to sound with only its 16 Ohm speaker connected (louder/quieter/darker), and how safe would that be to run?



Yes it's OK.
Is the amp set to 16 ohms?


----------



## mickeydg5

Its solid state with minimum 8 ohms, 65W.
A single 16 ohm speaker will drop power output level lower and maybe be less bright and full.


----------



## SkyMonkey

The VS65R has no speaker settings as such, only a single 8 Ohm speaker connected by wires coming from inside the "Head" portion of the combo. It is one of the Valvestate II line and has "Output 65 watts RMS - 8 Ohms" printed on the back. There are no extension speaker jacks, which is why I am attempting to wire in a speaker cable extension lead from the built-in speaker tabs for a separate cab connection.

I know this amp probably does not deserve this kind of attention, but I've got the cab and speakers so I thought I'd have a go. Projects keep me out of trouble!


----------



## mickeydg5

The VS265R is kind of a similar amplifier with extension jack. It has the same "Output 65 watts RMS - 8 Ohms" with the difference being that the extension cabinet is placed in series with the internal speaker.
So 8 + whaterver 4 to 16 ohm cabinet is total impedance. Yes it drops the power output of the amplifier but the additional speaker(s) add acoustic power.


----------



## BowerR64

If i were you ide be careful dinking around with speakers and wiring with those amps they will blow up if the wind blows in the wrong direction.

Ide keep the ohms at 16 and DO NOT EVER go below 8 with those amps they will fry quick as shit. They have very poor cooling and those output chips are super fragile. They sound good and look kickass ive had 2 of the 50 watt heads, one of the 150 watt 4 channel and one of the 50 watt combos all of them had blown at least once the 50 watt combo blew i fixed it and the stock right angle speaker cord was shorted and before i figured out what it was it blew a second time. Those molded speaker cable are junk also get rid of it also before it fails.

The reason why i say run the amp at 16 ohms is because it runs cooler at 16 so you have less of a chance of nuking it.


----------



## SkyMonkey

My VS65R has no moulded speaker cord, just the type of wiring you would expect to find inside a speaker cab. Single red and black wires, spaded.
I have two 16 Ohm speakers ready to use in parallel, but do also have two 8 Ohm speakers I could run in series.
It is good to know that running the amp at 16 Ohms with one internal speaker might actually extend the life of the amp.
It's 22 years old already!


----------



## Georgiatec

You will need to use the two 16 ohm speakers you have. one in the combo and one in the extension cab. Run the + and - from the amp speaker to a jack socket and fix it into the back panel of the combo. You now have an extension output for another 16 ohm load. You will be running at 8 ohms with the extension connected and 16 without.


----------



## ampmadscientist

SkyMonkey said:


> The VS65R has no speaker settings as such, only a single 8 Ohm speaker connected by wires coming from inside the "Head" portion of the combo. It is one of the Valvestate II line and has "Output 65 watts RMS - 8 Ohms" printed on the back. There are no extension speaker jacks, which is why I am attempting to wire in a speaker cable extension lead from the built-in speaker tabs for a separate cab connection.
> 
> I know this amp probably does not deserve this kind of attention, but I've got the cab and speakers so I thought I'd have a go. Projects keep me out of trouble!



16 ohms is a good load on an 8 ohm solid state amp.
It's OK.


----------



## SkyMonkey

Made the mods and tested it. All is good. A 1912 cab underneath is the perfect match for the VS65R.
Changed the tube for a JJ ECC83 and now this amp rocks.

Cheers for the help guys.​


----------



## Lukas

Funny I was questioning my connections today after years. Seems like such an easy thing but it’s not really explained well anywhere I don’t think. Maybe it’s the way the jacks are labeled that makes it this way. Anyway, this is the back of my JVM and it is connected to 2 1960 A&B cabs to equal a full stack. I hope this is correct? Nothing has made smoke yet in about 8 years.


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## Matthews Guitars

As it says, use those jacks for 1 8 ohm cabinet or two 16 ohm cabinets. Since your 1960A/B cabinets are both 16 ohm cabinets, you're plugged into the right jacks.


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## mickeydg5

Hopefully they are set for 16 ohms. 
Oh, of course they are.


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## Lukas

So if I have a buddy come over with a Mesa head and I wanna split this full stack into two half stacks so he can play through one he can’t? I believe Mesa cabs are all 8ohm and the back of Mesa heads only have 8 ohm options not 16? Or it will power it at 8 but not to it’s full potential?


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## mickeydg5

Lukas said:


> So if I have a buddy come over with a Mesa head and I wanna split this full stack into two half stacks so he can play through one he can’t? I believe Mesa cabs are all 8ohm and the back of Mesa heads only have 8 ohm options not 16? Or it will power it at 8 but not to it’s full potential?


Which year and model Mesa head?
A lot of Mesa Boogie have 8 and 4 ohm impedance out so in that case he could use the 4 ohm mono option.


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## Lukas

mickeydg5 said:


> Which year and model Mesa head?
> A lot of Mesa Boogie have 8 and 4 ohm impedance out so in that case he could use the 4 ohm mono option.


Mark V... around 5 years old. Dont think the impedance at the back have changed in the last 10 years.


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## BatmansMarshall

My EVH 5150III 50W has a three-way load impedance switch 4/8/16 OHM.

My Marshall Origin 50W has a 16 OHM Output and 2 x 8 OHM Outputs.

I currently own an 8 OHM 50W speaker. There is the possibility of connecting it to another cab in a series. I am thinking of buying another 8 OHM speaker.

So, 

2 x 8 Ohm Speaker = 8 + 8 = 16 Ohm Load

So for both amps used separately, I just use their 16 OHM outputs? EVH set to 16 OHM and Origin's 16 OHM output? It would be nice to be able to just change heads and carry on.

Do I have this right?


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## ampmadscientist

BatmansMarshall said:


> My EVH 5150III 50W has a three-way load impedance switch 4/8/16 OHM.
> 
> My Marshall Origin 50W has a 16 OHM Output and 2 x 8 OHM Outputs.
> 
> I currently own an 8 OHM 50W speaker. There is the possibility of connecting it to another cab in a series. I am thinking of buying another 8 OHM speaker.
> 
> So,
> 
> 2 x 8 Ohm Speaker = 8 + 8 = 16 Ohm Load
> 
> So for both amps used separately, I just use their 16 OHM outputs? EVH set to 16 OHM and Origin's 16 OHM output? It would be nice to be able to just change heads and carry on.
> 
> Do I have this right?



No
The speakers are in parallel.
2X 8 ohm = 4 ohm

Formula for parallel

Speaker A X speaker B
------------------------ == Total load
Speaker A + speaker B

Speaker A 8 ohms X speaker B 8 ohms = 64
Speaker A + speaker B = 16

64
----- = 4 ohms
16


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## BatmansMarshall

ampmadscientist said:


> No
> The speakers are in parallel.
> 2X 8 ohm = 4 ohm
> 
> Formula for parallel
> 
> Speaker A X speaker B
> ------------------------ == Total load
> Speaker A + speaker B
> 
> Speaker A 8 ohms X speaker B 8 ohms = 64
> Speaker A + speaker B = 16
> 
> 64
> ----- = 4 ohms
> 16



Okay so basically daisy-chaining 2 x 8 ohms separate cabs with a single speaker in each means I need to use the 4 ohms out. The Marshall Origin 50 doesn't have that. The EVH 5150 III does. What are my options?

What I can do is replace one of the 8 ohm with a 16 ohm version of the same speaker and instead of getting another 8 ohm cab get a 16 ohm. So go with 2 x 16 ohm instead?

Speaker A 16 ohms X speaker B 16 ohms = 256
Speaker A 16 + speaker B 16 = 32

256
----- = 8 ohms
32

Meaning use the 8 ohms out of both amps for that daisy chaining of two cabs with a single 16 ohm speaker in each?


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## ampmadscientist

BatmansMarshall said:


> Okay so basically daisy-chaining 2 x 8 ohms separate cabs with a single speaker in each means I need to use the 4 ohms out. The Marshall Origin 50 doesn't have that. The EVH 5150 III does. What are my options?
> 
> What I can do is replace one of the 8 ohm with a 16 ohm version of the same speaker and instead of getting another 8 ohm cab get a 16 ohm. So go with 2 x 16 ohm instead?
> 
> Speaker A 16 ohms X speaker B 16 ohms = 256
> Speaker A 16 + speaker B 16 = 32
> 
> 256
> ----- = 8 ohms
> 32
> 
> Meaning use the 8 ohms out of both amps for that daisy chaining of two cabs with a single 16 ohm speaker in each?



I'm sorry you lost me.

How many cabinets do you have? two?
How many speakers are in each cabinet?
What is the ohms of each individual speaker in the cabinets?
I'm looking for possibility of re-wiring the cabinets to make a match to the amp if possible.

You can't hook the same speakers up to 2 amps at the same time.
But from what you are writing, it sounds like you plan to do that.

"8 ohm out of both amps for that daisy chaining..."

I have no clue what you are doing. Try explaining it a different way.
Or draw a picture.


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## BatmansMarshall

ampmadscientist said:


> I'm sorry you lost me.
> 
> How many cabinets do you have? two?
> How many speakers are in each cabinet?
> What is the ohms of each individual speaker in the cabinets?
> I'm looking for possibility of re-wiring the cabinets to make a match to the amp if possible.
> 
> You can't hook the same speakers up to 2 amps at the same time.
> But from what you are writing, it sounds like you plan to do that.
> 
> "8 ohm out of both amps for that daisy chaining..."
> 
> I have no clue what you are doing. Try explaining it a different way.
> Or draw a picture.



This is the setup I want. Except I have mismatched cabs. One is 8. The other is 16. So I can't do this.






I only want to use one amp at a time. To be able to switch out the heads. Marshall for Marshall tones, EVH for EVH tones depending on what I am playing. So I will literally be disconnecting a head and putting the other in. You'll only see one head connected to my rig at any one time.

I want to stack two single speaker cabs. 1 x 12 on top of another 1 x 12.

One of those cabs is 8 ohms. The other is 16 ohms.

They are mismatched so I can't simply hook one cabs out to the other cabs in like in the diagram.

I have two choices it seems. I can either take out the 8 ohms and replace with a 16 ohms.... or take out the 16 ohms and replace with an 8.

If I go the 16s route, then it's the graphic isn't it? 8 ohms is what I set on both heads and I don't need to change that. Just switch them out.

If I go the 8s route, then what would that be? 4 ohms. Which is really too low for my amps I would think.

So it seems the 16s route might be what I need to do?


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## BatmansMarshall

So I am going to replace an 8ohm with a 16 ohm. That way I have two 16 ohm cabs and can hook it up from the amps 8 ohm output the way it is presented in the diagram.


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## BatmansMarshall

I am hoping to break in the Swamp Thang eventually and figure out where it goes with this setup. Thanks everyone for the help. Oh and I still love my Marshall Origin 50 and can't wait to experiment the same way. I wonder what Eminence works well with them?







BTW, if you are asking why stacked this way the answer is because the Eminence is an open back and the PPC112 is closed so is structurally better at the bottom.


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