Attenuator Thread

colchar

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I agree with the above. The Plexi circuit is about blending the high and low side.

Look at my image to your left.

That's what is referred to as Jumping the 4 Holes. You can reverse it and run your instrument cable into the low side. I suggest you do both and adjust the amp's controls without looking at the numbers. A Les Paul or any humbucker begs for the high side. That being said, i run a Strat into the high side as well. Speaker types also matter.

A Tele bridge pickup is already kind of spikey so try to roll off some highs on your guitar. Plexi type amps require using your on board guitar circuits to match what you are playing.

Set the amp up however you want, but I would suggest begin the initial set-up on Low Power (5 watts) and then try Jumper A (high input) and Jumper B (low input) and each time place all the knobs on 0 (minimum) then simultaneously increase the High Treble and Normal side until the amp begins to break up.

Don't use any of the EQ or Presence until the High side and Normal are close to sounding okay. Rarely does anyone ever crank these gain channels and they usually end up between 11 and 2 on the clock dial. Adjust to taste, etc.

Once you have some gain and the amp is breaking up but isn't excessive, then begin SLOWLY increasing the EQ. Once the EQ is close, then add some Presence. EQ settings rarely go above noon. Usually less. This is speaker and cabinet dependent, but you get the idea.

At this point you are getting close, but then go back to tweaking both gain knobs. The EQ side activates those circuits to complement the natural tones of the preamp/gain side. Also note, the SV20h is a "power amp" focused amp. The tones everyone chases are on the power amp side. The preamp and EQ helps push it, but isn't the primary basis for the final tone. This is hard to explain.

Everyone does this different, but a Plexi type amp requires a different approach to get THAT sound.

Make sure the amp is set to run on the neck pickup and not sound too muffled. When you switch to the bridge pickup, expect to roll off some highs on the guitar.

Again, there's no one way to do this. Just keep experimenting, but part of the tone is rolling off the guitar volume maybe 10-30% and always leaving enough room on the volume for that extra push.

A good boost pedal or mild drive pedal goes a long way with the SV20h. Hitting an amp that's already into break up doesn't require much to push into that glorious Plexi sound.

Speakers make a difference in taming the spike of a Tele, Strat, etc.


This is great, thanks. As soon as I actually have toime to mess around with it, I will follow this advice.
 

leofender55

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If you're not playing live any more and are looking to sell that amp.............:D
Thanks for the offer, but that amp is staying with me. It's a special amp. Years ago I found an article from and amp tech in England who used a reissue to mod to something close to Clapton's Beano Bluesbreaker. I was able to get a schematic from the guy and took my amp to Ben Fargen to see if he could duplicate it. The cab in my amp was able to fit the Gold Lion KT66 power tubes (apparently some can't), and Fargen used Mercury Magnetics transformers and his own spec of Sozo caps and some other tone shaping mods. It sounds amazing and I've played it side by side with other reissues. This amp is what started Fargen on his Hot Mod series.
 

colchar

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Thanks for the offer, but that amp is staying with me. It's a special amp. Years ago I found an article from and amp tech in England who used a reissue to mod to something close to Clapton's Beano Bluesbreaker. I was able to get a schematic from the guy and took my amp to Ben Fargen to see if he could duplicate it. The cab in my amp was able to fit the Gold Lion KT66 power tubes (apparently some can't), and Fargen used Mercury Magnetics transformers and his own spec of Sozo caps and some other tone shaping mods. It sounds amazing and I've played it side by side with other reissues. This amp is what started Fargen on his Hot Mod series.


But based on your user name you should be playing an entirely different brand of amp.................
 

OriginOfTheSpecies

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I'll need to spend some more time with it and do some back and forth with the captor.
So I ended up selling the captor to a work mate.
The P&P 50 sounded more transparent to me with my Origin 20 and T75/Greenback cab, if anything it adds a bit of a percussive thump, where as the Captor adds a bit more upper mid edge that would work well for some purposes. The combo of Origin power scaling and stepped attenuation settings has really let me get solid cranked Marshall tone at polite home practicing levels.
The captor is still a great bit of kit. I didn't get a chance to compare them as a pure load box but maybe the captor would edge ahead there.
 

JohnH

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There's a few references to Bugera PS-1 attenuators on this thread, and I've been reading more about them. I found something in the manual that concerned me:

"Long periods of use at maximum input power may trip the thermal circuit protection. Allow some time for cooling down, before your PS1 will be fully operational again."

If a device is rated for a certain power, it should be safe to use at that power for for a long time. The note above implies the attenuator will cut out if driven at max for extended time, to avoid overheating. That's all great as a way to protect this $100 attenuator. But what will happen to the $1000 amp? If the attenuator is cutting out, it sounds like it is then no longer dissipating power from the amp?

So does it go open-circuit? With no load on the amp? And the amp was blasting at high power so good-bye amp?

I'm just speculating ..I don't know for sure
 

colchar

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There's a few references to Bugera PS-1 attenuators on this thread, and I've been reading more about them. I found something in the manual that concerned me:

"Long periods of use at maximum input power may trip the thermal circuit protection. Allow some time for cooling down, before your PS1 will be fully operational again."

If a device is rated for a certain power, it should be safe to use at that power for for a long time. The note above implies the attenuator will cut out if driven at max for extended time, to avoid overheating. That's all great as a way to protect this $100 attenuator. But what will happen to the $1000 amp? If the attenuator is cutting out, it sounds like it is then no longer dissipating power from the amp?

So does it go open-circuit? With no load on the amp? And the amp was blasting at high power so good-bye amp?

I'm just speculating ..I don't know for sure


I believe that is a clone of the Jettneuator. I have a Jettenuator, and there is no heat whatsoever from it so I think that for those looking at that type/model/style of attenuator it would be best to search out an actual Jettenuator rather than any of the clones.
 

Rokinroller

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Many good points here . But to me attenuators are akin to stuffing potatos in a hot-rod's tail pipes . Over-revving and Suffocating the engine , and at the same time like diving the car while flooring it with the brakes on . I will never use attenuators . I use the simple , smart , effective and harmless master volume on the amp . No harm done to amp . Use them at your own risk . Tubes and transformers are not cheap . If I'm out looking to buy a used amp and find out the guy uses attenuators , I dont buy his amp . YMMV
 

Tonneback

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I managed to find a Palmer PDI06L08 here in Sweden. Checked a frew Youtube clips reviewing it and it seems quite good. Anybody here having any input about it? My pricelimit is around there at the moment
 
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I've used many attenuators of various types. Currently swear by Waza Tube Amp Expander - it's the perfect piece of kit, both live and in the studio. Similar to Fryette, but more versatile.
Before I had:
- Rivera rock Crusher (very good)
- Bugera PS1 (crap)
- Dr Z Brake Lite (good for live use, not quiet enough for home)
- Two Notes Torpedo Captor (fixed -20db... useless)
- JHS Black Box (useless if you want power tubes overdriven)
- SPL Reducer (not bad, but too expensive for what it can do).

My ideal would be a pedal-sized Waza TAE of a Fryette.... Just a matter of time, I guess.
 

Gene Ballzz

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PSA

I guess this is a good place as any to post this?
Sweetwater has a Black Friday deal going on for the Bugera PS1 100 Attenuator for only $49 right now. I have no use for an attenuator myself but figured others may want to jump on the deal while they can. :)

https://www.sweetwater.com/store/detail/PS1Atten--bugera-ps1-passive-100-watt-power-attenuator

Good deal on the PS-1 right now at Sweetwater. View attachment 119643

Sorry folks, but that is not even close to a deal! There is only one "sub $500" attenuator design worth spending even a penny on! That is even the simplest @JohnH M2 design featured in the link below. The price to build it ranges $100-$135 and to have someone do it for you should range between $275 & $310. It retains tone, feel and dynamic response like none of the others can! Now, with that said, IF a player derives almost all their sound, tone and character through the use of pedal/stomp/foot/thingies, they may not notice all that is lost with the inferior products, but for one who plugs generally straight into the amp and drives it to tonal bliss, the differences will be clearly evident!


Simply Attenuatin'
Gene
 

colchar

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Many good points here . But to me attenuators are akin to stuffing potatos in a hot-rod's tail pipes . Over-revving and Suffocating the engine , and at the same time like diving the car while flooring it with the brakes on . I will never use attenuators . I use the simple , smart , effective and harmless master volume on the amp . No harm done to amp . Use them at your own risk . Tubes and transformers are not cheap . If I'm out looking to buy a used amp and find out the guy uses attenuators , I dont buy his amp . YMMV


Not all amps have master volumes.

And do you have any verifiable proof that attenuators damage amps, or is it just opinion?
 

JohnH

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Properly designed attenuators do not cause damage to well functioing amps, beyond just somewhat increased valve wear because they are driving harder.

But a faulty amp may reveal its faults when driven harder. And some attenuator designs are very relaxed about maintaining suitable load on the amp and this may cause or reveal amp problems. But none of that applies to the attenuators that we build on this forum!
 

MikiDord smf

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Great topic and sharing. I like it.. i made mistake thinking that is DIY about attentaours , sorry for that. Probably i mixed up 2 topics on my PC. pardon me for that. Still it's great topic.
I have one of my older DIY and latest i got was ala 50ish $ great attenuators which is similar to one ''famous'' which cost around 500$/Euros. But that company don't sell any more, it was imported from Asia and they put brand name of that shop ''fame''.
Anyhow i don't think that there is any need for so called reactive modern, because they promise imposable. Reason is simple law of energy transformation and signal. So ''usual'' attentaours are imho good thing and people can make them alone. if they wish to.
 
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ITburst

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Forgive me as I have looked up this thread for an answer but just skipped to the end [cause I need to leave the computer all of a sudden!}
But I read over and over that one must crank their amp to get the true sound. The cone needs to move...properly...to move some air. Thats where the true sound comes from.
So, does an attenuator not render this moot? If I have a master volume such as on my DSL20 HR do I still benefit from an attenuator?
 

mallcorn

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Forgive me as I have looked up this thread for an answer but just skipped to the end [cause I need to leave the computer all of a sudden!}
But I read over and over that one must crank their amp to get the true sound. The cone needs to move...properly...to move some air. Thats where the true sound comes from.
So, does an attenuator not render this moot? If I have a master volume such as on my DSL20 HR do I still benefit from an attenuator?
You do not need an attenuator.
 

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