# Plexi Vs Metalface



## Marshallguy

2 questions in one thread 

1) Would you post a picture where I can see the difference between pelxi and metalface front panels? (also a PCB if possible)

2) Which one do you prefere? (in terms of tone) and why?


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## PeteTheRock

For example a model 1959 super lead from 1968 with a plexi front has no difference to a model 1959 super lead from 1970 with aluminum front except the front. I reccomend to buy Doyle's Marshall book, there you can see all you want to see and to know.
I prefer the 50 Watt models, either the 1987 (look at my avatar) or the 2204 series.
The are alway loud enough in combination with a 4x12 cab to rock medium sized clubs without a P.A. and it's more easy to get power valve saturation then with the 100 W models.
My one is a 1987 model from the year 1971 and its a real burner


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## subcity138

pete
this is what spins my head
"1959 super lead from 1968"
and
"1987 model from the year 1971"

have you re-capped them with flux capacitors?

i just dont get the date name date thing , its far too confusing


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## Guv'nor

PeteTheRock said:


> For example a model 1959 super lead from 1968 with a plexi front has no difference to a model 1959 super lead from 1970 with aluminum front except the front.



I'd say the difference (in tone) comes after 1973 when amps were not PTP anymore. Became then much brighter and more aggressive than the Plexi era circuit

Do you agree on that?


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## ant1991

what the hell is a metal face i cant find it on the marshall site


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## MarshallForum

ant1991 said:


> what the hell is a metal face i cant find it on the marshall site



I am preparing something that will clarify this point and some others.

Please be patient. It will be ready very soon.


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## PeteTheRock

Guv'nor said:


> PeteTheRock said:
> 
> 
> 
> For example a model 1959 super lead from 1968 with a plexi front has no difference to a model 1959 super lead from 1970 with aluminum front except the front.
> 
> 
> 
> 
> I'd say the difference (in tone) comes after 1973 when amps were not PTP anymore. Became then much brighter and more aggressive than the Plexi era circuit
> 
> Do you agree on that?
Click to expand...


I agree. Taking for example my amp from 1971 or the 100 Watter from 1970 I once owned you were able to figure out their Fender Bassman roots. Thay never sounded shrill and , never too agressive compared to the later specimen.


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## PeteTheRock

ant1991 said:


> what the hell is a metal face i cant find it on the marshall site



metal front or metal panell would be the right term


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## PeteTheRock

subcity138 said:


> pete
> this is what spins my head
> "1959 super lead from 1968"
> and
> "1987 model from the year 1971"
> 
> have you re-capped them with flux capacitors?
> 
> i just dont get the date name date thing , its far too confusing



The Superlead from 1968 belongs to a friend of mine, the 50 W small box I own had been found by incident in a basement several years ago. It had been standing there unused for about 16 years an the friendly owner sold to me because he wasn't playing anymore.


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## subcity138

sorry mate , bad joke

i just find the naming of some of the marshall`s confusing 

a flux capacitor is how marty mc fly travells back to the future


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## Guv'nor

subcity138 said:


> a flux capacitor is how marty mc fly travells back to the future



Flux Capacitor..... Essential item in any Time Machine.


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## PeteTheRock

subcity138 said:


> sorry mate , bad joke
> 
> i just find the naming of some of the marshall`s confusing
> 
> a flux capacitor is how marty mc fly travells back to the future



I know, but if I had a flux I would buy a couple of '59 Paulas


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## sickboy79

Both are great, just different:

Plexi = warmer, smoother, more clean headroom

Early metal face (late 69-71) = essensially the same circuit as above, minor differences here and there.

72-later metal face = more aggressive, brighter ,more gain but, still in a classic rockin tone. 

Both have their place. Use your ears. From a collectability standpoint, Plexi's will always be worth more.


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## swankmotee

I'm really partial to my 73's (both PTP & PCB) for the classic Marshall tone but this is very much dependent on where the amps components have drifted to in value and condition. One of the biggest problems in why some sound so clean and shrill is because voltages on the preamp tubes go higher than stock and the thing has no crunch. There are many other things that could cause them to be too bright though but with some TLC they can be brought back to their former glory easily! They are definitely more aggressive in nature but can sound fabulous for clean as well if outfitted with NOS tubes.


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## Joshabr1

Guv'nor said:


> I'd say the difference (in tone) comes after 1973 when amps were not PTP anymore. Became then much brighter and more aggressive than the Plexi era circuit
> 
> Do you agree on that?



Not to bring up an ancient thread but why do we think that pcb and turret board construction sounds different?? That makes zero sense. The reason the amps got more aggressive is the negitive feedback changed from 47k on 8 ohms to 100k on 4ohms. Huge difference in the feel and breakup character of the amps. Along with the transformer change from c1998 with paper insulation to 2373 or 2668 with nylon which gives a slighly brighter more aggresive sound. Also the filtering changed in 68-9 to a stiffer feel. Pcb to handwired means nothing to sound. Absolutely nothing! I've owned both types and have sold em all except a few 73s with pcb construction. They sound every bit as good as any handwired amp I've heard. U can take a 73 superlead change the negative feedback to 47k hooked to 8ohm tap, change the bright cap from 5000pf to 100pf and there u have a much more plexi sounding amp.


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## jack daniels

ant1991 said:


> what the hell is a metal face i cant find it on the marshall site



The vintage Marshall forums refer to them as "Ali" aluminum panels vs. "Plexi" plexiglass panels.


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## jack daniels

Guv'nor said:


> I'd say the difference (in tone) comes after 1973 when amps were not PTP anymore. Became then much brighter and more aggressive than the Plexi era circuit
> 
> Do you agree on that?



Somebody here pointed out to me that there are some exceptions to the 73' rule (some turret board and some PCB).


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## Joshabr1

The change happened in the second half of 73. No certian day were they stopped. Some amps kept turret boards longer. P.A amps stayed longer. Never seen a 74 with a turret board.


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## jack daniels

The sound difference comes from tube versus SS rectification and those particular Marshall heads that provided higher B+ voltages such as 500VDC and higher. More so than the board differences.


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## Swede

I believe the newer 1987 X reissues are actually ca 1973 metal face reissues? even though they are often referred to as plexis?


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## jack daniels

Joshabr1 said:


> The change happened in the second half of 73. No certian day were they stopped. Some amps kept turret boards longer. P.A amps stayed longer. Never seen a 74 with a turret board.



If you saw mine you would, of course it was done 33 years later with NOS parts but, better late than never.


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## jack daniels

Swede said:


> I believe the newer 1987 X reissues are actually ca 1973 metal face reissues? even though they are often referred to as plexis?



That is very misleading to the consumer because Marshall is using "plexi" panels on reissues of a JMP era inspired "ali" panel. Only thing I can figure is that plexiglass is now cheaper than aluminum.


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## soundboy57

I have '67, '71, '72 and '74 50 watt heads in original untouched condition.
They all sound killer, but the '67 seems to have it all. Just juicier, fatter, chimier..maybe I am biased because of the plastic panel
Maybe it's the NOS Mullards, but the small box '67 and '71 are the most fun to crank to about 8

The '71 is a little warmer and sweeter.
The '72 is by far the most aggressive and dirty, just like they say. Barks like Craigslist date.
The '74 is a bit cleaner until you crank it up, but very singing tone, and nice chime, too.


As far as looks, the '67 wins due to the gold logo
The panels all look the same 5 feet away...

1967




1971




1972




1974


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## jack daniels

sounboy57, I played my Gibson 93' ES-335 last night into my KeeleyBoss BD-2 ---> JTM50 w/NOS GT Siemens EL34's, NOS GT Mullard 12AX7's, and a NOS Mullard GZ34 ---> Hiwatt 4122 cabinet with cast frame 50W Fanes and was pleasantly surprised. The lows are deeper and punchier than any Celestion speakers I've ever heard. What I thought to be a lack of mids with the Hiwatt/Fane cabinet had more to do with my aluminum panel 74' SL MkII converted to 68' 12000 specs. This JTM50 head was just what was needed to drive the Hiwatt cabinet and make it sing. I'm now a true Hiwatt cab convert, and the JTM50 isn't so darn bad either.


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## sct13

68 Plexi Panel 

Green Tolex Small box 50 watt






Guts of the same amp


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## jack daniels

sct13 said:


> 68 Plexi Panel
> 
> Green Tolex Small box 50 watt
> 
> 
> 
> 
> 
> 
> Guts of the same amp



Schweeeet!


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## Swede

holy mackerel.......In my eyes NO Marshall look better than a Plexi.........DROOOLLLL!


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## dreyn77

The rest of the amp was covered in pretective coating so the control panel was covered also. 
it's got nothing to do with any other perspective. 

Metal is fine as a hard wearing protective layer so why complicate matters/ production, you guys never wipe down the panel after playing anyway. 

70's home stereos were all about showing off the aluminium control panel anyway. 

the 60's was a off shoot of the 20's and 30's bakerlight radio's with the glass panel and then clear plastic panel. 

so your metal panel says '70's' and the clear plastic says '60's'. 

80's became black plastic and the 90's was all over the place with no design asthetic, it was probably the period of 'anti uniform design'.

the heavy duty roaduse influence marshall is the best.  metal panel baby!


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## dash8311

soundboy57 said:


> Barks like a Craigslist date.



Lol...


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## lew81

subcity138 said:


> pete
> this is what spins my head
> "1959 super lead from 1968"
> and
> "1987 model from the year 1971"
> 
> have you re-capped them with flux capacitors?
> 
> i just dont get the date name date thing , its far too confusing



1959 and 1987 are the model numbers and not the year.

They should have used a model number like 100SL and 50SL for the Super Leads, 100SB and 50SB for the Super Bass etc etc, would've made more sense.


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## Joshabr1

jack daniels said:


> The sound difference comes from tube versus SS rectification and those particular Marshall heads that provided higher B+ voltages such as 500VDC and higher. More so than the board differences.



No production 100watter or any amp with 500vdc ever had a tube rectifier. A prototype or 2 were built with 2 gz34s. But none I've ever seen had a tube rectifier. Also it was phased out in 67 on the 50 watters way before the switch to metal panels.


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## Joshabr1

jack daniels said:


> If you saw mine you would, of course it was done 33 years later with NOS parts but, better late than never.



I'm speaking of original marshall amplifiers only. Which is what the thread was started to discuss I believe. You could put a ptp board in a tsl if u keep the circuit and values the same it will still sound like a tsl. The only advantage of turret boards to speak of is the fact they are easier to work on. For sound quality it makes no difference. The signal does not know the difference between a lead and a trace. That's fact. Tubes, transformers, rectification,resistors, capacitors, and thier values and placement makes the sound of an amplifier and only those things affect its tone. The type of chassis or board or box you put in or on means dick.


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## jack daniels

Joshabr1 said:


> No production 100watter or any amp with 500vdc ever had a tube rectifier. A prototype or 2 were built with 2 gz34s. But none I've ever seen had a tube rectifier. Also it was phased out in 67 on the 50 watters way before the switch to metal panels.



Who in the hell said they ever did? Obviously you're confusing me for someone else.

** Assumption is the mother of all fook ups, and you're making very large ones. **


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## jack daniels

Or what do you get when you take a MF members words out of context? Answer - Joshabr1


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## yladrd61

Joshabr1 said:


> Not to bring up an ancient thread but why do we think that pcb and turret board construction sounds different?? That makes zero sense. The reason the amps got more aggressive is the negitive feedback changed from 47k on 8 ohms to 100k on 4ohms. Huge difference in the feel and breakup character of the amps. Along with the transformer change from c1998 with paper insulation to 2373 or 2668 with nylon which gives a slighly brighter more aggresive sound. Also the filtering changed in 68-9 to a stiffer feel. Pcb to handwired means nothing to sound. Absolutely nothing! I've owned both types and have sold em all except a few 73s with pcb construction. They sound every bit as good as any handwired amp I've heard. U can take a 73 superlead change the negative feedback to 47k hooked to 8ohm tap, change the bright cap from 5000pf to 100pf and there u have a much more plexi sounding amp.



Yes this definitely had more of an effect on the tone of the amp than the change from turret board to pcb.. The '68 also had 820ohm/.68uf on the bright channel, and no .68uf cathode bypass cap, which also make for a much warmer and less aggressive sounding amp...


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## Joshabr1

jack daniels said:


> Or what do you get when you take a MF members words out of context? Answer - Joshabr1



U need to read the comment at the top of this page that u made that I quoted.


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## Joshabr1

U said and I quote "the sound difference comes from tube versus solid state rectification and those particular marshall head which provided higher b+ voltages such as 500vdc and higher" which is not true in anyway. You said the amps have 500vdc and higher so that means you are talking about a 100watt amp. No 100 watt amp where ever tube rectified so how can that be the sound difference between plexi and metal panel?? It's not. Misinformation needs to be corrected. I don't know if I read your text wrong but I wasn't trying to call u out. Just correct what I thought was misleading info.


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## blues_n_cues

subcity138 said:


> pete
> this is what spins my head
> "1959 super lead from 1968"
> and
> "1987 model from the year 1971"
> 
> 
> i just dont get the date name date thing , its far too confusing



I don't think it was much of a concern back then. from the history it seems they were far too busy sourcing parts & getting units out the door to meet sales figures than worrying about model numbers making sense.


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## jack daniels

Joshabr1 said:


> U said and I quote "the sound difference comes from tube versus solid state rectification and those particular marshall head which provided higher b+ voltages such as 500vdc and higher" which is not true in anyway. You said the amps have 500vdc and higher so that means you are talking about a 100watt amp. No 100 watt amp where ever tube rectified so how can that be the sound difference between plexi and metal panel?? It's not. Misinformation needs to be corrected. I don't know if I read your text wrong but I wasn't trying to call u out. Just correct what I thought was misleading info.



Keyword(s) underlined.


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## neikeel

jack daniels said:


> The sound difference comes from tube versus SS rectification and those particular Marshall heads that provided higher B+ voltages such as 500VDC and higher. More so than the board differences.


 
Only partly true. jack daniels you did imply what joshabr1 referred to at leastin my opinion
Let's break it down simply into 50w and 100w.

50w amps with Drake 1202-118PT and GZ34 run about 420vdc after the rectifier, the rarer -133PT a bit higher, maybe 450-460v,_ never_ 500v.
The first SS rectified amps are around the same B+ but do have less of that tube rectifier sag when pushed. Of course there is little to tell the casual player which 50w plexi you are playing without the numbers (1985=PA, 1985=Bass, 1987=Lead and 1989=Organ) or a look inside. The lead circuit was the one that developed over the years with circuit changes that developed to a brighter more cutting tone (split V1 cathode, tone stack tweaked for more upper mids, NFB changes for earlier crunch and break up/distortion and smaller PI output cap couplers. As the upright PTs came in (1202-164) the B+ started to come down too (late 70s into th370-380v area), screen resistors were introduced.
IMO it is the NFB and presence changes that made the most difference between metal panel and plexi amps, we know that PCB makes absolutely no tonal difference in these.

As Joshabr-1 said no tube rectifed 100w amps ever hit the streets, Marshall struggled with dual OTs in the first 45/100 amps until the 4k Drake 1202-84 came out. Yes they had massive 1204-43PT which would push 560v and more with mains variation. The early RS PT is a relatively wimpy affair and the amp probably only makes 80wRMS with its KT66s (when I have the one on my bench tidied I still the 'scope on and let you know how much).
Later 100w amps were developed in the same way electronically to become brighter and brasher (again NFB and presence), my '67 EL34 45/100 (480v B+ with dual rectifiers) is much smoother and easier to control than the '68SL (490v B+), at least in my hands. That is partly due to preamp changes that I referred to above and the change from 2" Drake (1202-119) to the 1 1/2" Dagnall (C1998). Later Dagnalls were a bit brighter too (C2668) and shortl lived equivalent Drake-99 from '71 onwards.
Like jackdaniels, I like my '67 JTM50 (I gig with it) but the '68 1987 gives more push and grind when you want to rock out. I sold all my aluminium (spelled correctly) metal panel amps a while back buth they have their place. Problem is the lettering rubs off when you actually use them.
Of course you need to think about which speakers you have in your 4x12 too but that is for another thread ;-).


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## sct13

this is good info. 

thanx


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## soundboy57

sct13 said:


> this is good info.
> 
> thanx



+1


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## Joshabr1

Neil knows this stuff as good as anybody anywhere. From the time I started reading forums and geeking out on old les Paul's and Marshall's his information has always been accurate and appreciated I owe all my limited knowledge of old marshall amps to guys like him soundboy57 Roe ken underwood tazin george76 and many others. These guys dont have to share knowledge they have taken years to acquire. But they do. We should respect them the upmost. Threads like this can really be helpful to understand actual differences between years and tone of these amps and what and what doesn't affect that.


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## sct13

Yes I am very thankfull to all of them, Jack has been helpfull and Mikydog5 is a guru....special thanx !


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## Joshabr1

I see you just came over Neil. It's awesome to have you here. Welcome.


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## Joshabr1

Yes. Your right. I only named a couple but their is a good heap of very knowledgable people here. Jack is very helpful and I was not trying to attack that in any way. I think I understood wrongly what he was trying to say. The thread was meant to discuss what makes a plexi sound different than a metal panel and Neil outlined that perfectly in his post.


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## Joshabr1

Mikydog5 has a huge amount of knowledge. Ur not born with that stuff you know. I think sometimes things can taken for granted. 20 years ago u had to take your amp to a tech if anything was wrong and then u had to trust that he's not a crook. Now you have a army of geeks who love the shit out of this stuff that don't care to take there time to help you and save you major$$ if u are careful and willing to learn. We really owe the whole thing to those guys. I named a few names and I shouldn't have because they know who they are and they don't help out for any reason other than that they want to in the first place. Anyways thanks guys


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## jack daniels

Your a good feller Josh, you can include yourself in that list


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## Joshabr1

Thanks jack. But I'm just a hack compared to what these guys know. I learn everyday something on here though. I've read more old threads than I recall. Read some of em way more than once. I love to know what makes em sound so damn good. It brings quite a bit of joy to my life to have em tweak em and hear em and also to have places like this to share it with kindred spirits.


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## jack daniels

I know that I've forgotten more than what I have learned. When I was younger I used to be really into it. Then I got busy purchasing right-of-way and being out of town all of the time so, the last thing I wanted to do was to repair my own amps. I had other techs to do my work (if needed) but, at least having a combined 4yrs of electronic schooling helped me to separate the wheat from the chaff when it came to knowledgeable electronic repair techs. I can still make mistakes and act like a noob sometimes regarding electronics but, what's important to me is if nothing else I am honest about my shortcomings.


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## Joshabr1

Being honest about shortcomings. Oh lord. Talking about a can of worms.


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## jack daniels

Don't open them!!!!


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## allwheelz

I've got a 78'metal face 1987 that has the plastic rockers and pcb board...gimmie a few minutes to get some pics lined up...this thing has been a tad modded and I just got it so I cant clarify what all has been done. It wasn't me though..lol


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## NativH

jack daniels said:


> Don't open them!!!!


Ah hell, why not?  The PTP vs PCB sound being the same, is predicated on them both having the exact same board components. Not the values, but the actual pieces. We all know (?) about the chicklet and tropical fish caps affecting the tone of some PTP metalpanels in the first few years of the 70's compared to the mustard loaded amps. Sure a pre-PCB '73 will sound like a PCB '73 because they both had mustard caps and Piher and/or Iskra resistors in the same circuit design. Even up through around '76 1987's were predominantly mustards, or at least the amps I owned were IIRC. But later PCB's deviated from mustards/Piher/Iskra and eventually Marshalls started looking like the insides of a Dell computer using micro components instead of the old full sized resistors and caps. 

Today a metalized polyester film Mallory 150 series .022 cap could be considered a standard bare bones 630V cap for a PTP build, and is a decent sounding cap IMHO, but that is not what Marshall uses in their micro component boards like I see in my bud's DSL's. I look at those boards and realize that component replacement is most likely impossible. And besides the possible, or probable, tonal differences in those micro component .022 caps, I can only imagine how they will drift differently in value with age. 

And component value drift can be a significant "component" to the sound of any amp especially those we love in the vintage section. I tell techs to leave my board components as is (other than bias caps), unless something is totally burned out, because component drift could give my amp its special sound. Or at least ask me before changing out a component. Don't just test everything and try to bring my amp back to original spec. 

So yeah, in a perfect straight heads up PTP vs PCB world, with the exact same components in each board, there should be zero difference in the tone assuming all other items such as tubes/transformers/etc are the same. But except for that brief period where Marshall used the exact same components in their first PCB's, say the '73 through last few years of the 70's 1987's and 1959's, Marshall pretty much quit using mustard caps and Piher/Iskra resistors. And even during that brief period you will find non-mustard caps in some non-mastervolume heads. So at the end of the day, I really wonder how much tonal difference can be contributed to the use of these new components (micro or not) over a full sized mustard cap or Vishay/Iskra resistor, in a PCB 1987 or 1959?


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## dreyn77

yeap, my dagnall c2668 is real nice and it's the right sound.  

stand at the point of projection and there's not going to be much difference in the sound comparison. 

but they've always listend to the players and added more. 

there's no point in getting the smooth amp and then use pedals or hot pickups. it defeats the purpose.


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## Joshabr1

A couple metal panels. Good ones!!!! My new 50 on top of my superbass. Different animals and I love 100s but damn this 50 has it. Narly sucker after a few tweaks to the proper proportions.


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## ampmadscientist

Marshallguy said:


> 2 questions in one thread
> 
> 1) Would you post a picture where I can see the difference between pelxi and metalface front panels? (also a PCB if possible)
> 
> 2) Which one do you prefere? (in terms of tone) and why?



They are very similar, not a big lot of difference.

We would prefer point to point just for ease of maintenance.
Hand wired is always a better investment, I think.


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## jerryjg

swankmotee said:


> I'm really partial to my 73's (both PTP & PCB) for the classic Marshall tone...



there is no such thing as a '73 pt. 2 pt. Marshall Superlead amp. The last pt. 2 pt. tagboard amps were early '72. By mid '72, and later, they were all circuitboard amps.


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## Joshabr1

jerryjg said:


> there is no such thing as a '73 pt. 2 pt. Marshall Superlead amp. The last pt. 2 pt. tagboard amps were early '72. By mid '72, and later, they were all circuitboard amps.[/quote
> 
> 
> 
> . Pcb amps started in 73 3rd or 4th quarter I would say. I had a superbass july, 73 inspection tag it was a turret board amp. No pcbs in 72.


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## Joshabr1

Although as stated before it wasn't a cut and dry switch like one day they were this and the next day they were that. Nothing happened that way in those days. Some models kept the turret board longer. PA amps kept it a while longer. I previously thought that pa amps never went to pcb but I recently seen a 74 that was pcb. They just cut the v1 part of another board and put it up front. It was cool looking.


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## FutureProf88

lew81 said:


> 1959 and 1987 are the model numbers and not the year.
> 
> They should have used a model number like 100SL and 50SL for the Super Leads, 100SB and 50SB for the Super Bass etc etc, would've made more sense.



The model numbers are because those were the product ID numbers in the Rose Morris catalog.


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## NativH

jerryjg said:


> there is no such thing as a '73 pt. 2 pt. Marshall Superlead amp. The last pt. 2 pt. tagboard amps were early '72. By mid '72, and later, they were all circuitboard amps.


 Sorry but my January '73 SL is definitely a tag board and I've seen tag board SL's into June of '73. 1227E is definitely a '73.


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