software

I'm new to the Marshall Plexi thing, so excuse my ignorance. I've seen these amps mentioned a lot on the board. Why are they so sought after?

Thx

J

three letters

EVH

=)

from : localhost/a read

As used by - Clapton(Cream) - Hendrix - Page - Kossof- Well Just about anybody late 60's to 70's and thats just the Brits

The very first Marshall amps had a plexiglass face plate...the Plexi pannels lasted until the very late 60's then Marshall switched to an aluminum face. Plexi Marshalls are simply the oldest Marshalls.

-Jimi
-Jimmy Page
-Jeff Beck
-Eric Clapton (on both the Bluesbreakers and Cream records)
-Peter Green (with the Bluesbreakers)
-EVH
-Angus

This is very short list of Plexi users...Go to the link that Rid provided and then click on Marshall info, thats a good start.


Originally Posted by the guy who invented fireThe very first Marshall amps had a plexiglass face plate...the Plexi pannels lasted until the very late 60's then Marshall switched to an aluminum face. Plexi Marshalls are simply the oldest Marshalls.

You're app. 3 years off The following can be read on the Marshall-site:

The following information is a rough guide to the major changes in the most popular Marshall models since 1962.

1962 - The original production of those first JTM45 models featured the following:- Serial numbers starting at 1004; Smooth black covering: White grill cloth: Silver polished aluminium panels: No rear panel: Rectangular metal logo with red block lettering: Leather handle: Single speaker output: 5881 or 6L6 valves. Cabinets - Straight fronted, using the same logo and fret cloth: Celestion G12 15 speakers.

1963 - Production essentially the same as the above but with the following changes:- Twin speaker outputs: Black knobs with serrated edges: Changed to white engraved panels late in 63: First angled cabinets, similar finish and speakers to the straights but taller than today's 4x12.

1964 - Serial numbers begin with 2: Valves now changed to KT66's: Logo changed to gold plastic with black lettering mid year: The first combos made late 64: Speakers now changed to G12 20's.

1965 - Panel changed to gold plexi glass: Serial numbers no longer reliable: Handles changed to plastic with larger end cap: The first 100 Watt amps appeared in larger cabinets with two 50 Watt transformers, JTM45 panels, KT 66 valves and without GZ34 rectifier. The first serious combo production of models 1961 4x10 and 1962 2x12 took place. The same features as the JTM45 but with the addition of tremolo. Fret cloth changed to green flecked weave late 65. The 'stack' was born from Pete Townshend's original request for an 8x12 cabinet. Late 1965 saw the change to green fret cloth.

even though the 1959 and 1987 Marshall models didn't have plexiglass panels after 1969, those amps are still often referred to as plexi's because of the Marshall 1959slp 'Plexi' Reissue - it's just become a generic term for the vintage NMV Marshall 4 input hole amp

Jeroen: You are right...I knew somebody would correct me on that! Good eye, and good call!


Originally Posted by shredaholiceven though the 1959 and 1987 Marshall models didn't have plexiglass panels after 1969, those amps are still often referred to as plexi's because of the Marshall 1959slp 'Plexi' Reissue - it's just become a generic term for the vintage NMV Marshall 4 input hole amp

Thats not really the case. Only the uninformed would refer to a metal face generically as a 'plexi'. The metal face amps that came later are different animals tone wise. Metal face varieties are generally,but not always, a bit brighter and crunchier. They are the quot;missing linkquot; if you will between the original plexi's and the first master volume amps which were of course followed by the JCM800 series. Marshall in those days would make undocumented circuit changes if something became unavailable or too expensive which changed the sound a bit obviously


Originally Posted by TheArchitectOnly the uninformed would refer to a metal face generically as a 'plexi'.

While this is true...I'd have to agree with Shred..cos most people really are misinformed and refer to old NMVs as plexis...just like everyone calls a Tremelo a Trem...when a Vibrato is the correct terminology...

That said I like the Metalface circuits better.. crunchy=good


Originally Posted by JeffBWhile this is true...I'd have to agree with Shred..cos most people really are misinformed and refer to old NMVs as plexis...just like everyone calls a Tremelo a Trem...when a Vibrato is the correct terminology...

That said I like the Metalface circuits better.. crunchy=good

On my early 70s MF Marshall I Made the quot;Plexiquot; circuit changes and beyond on my 1987 50 watt head...Things like the O.E.I Plexi transformer,adding the
.68 cap to V2's cathode,feedback,etc and it wasn't all magic ...gives you the quot;Plexiquot; era tone...Things like mentioned and transformer voltages do make differences in the tone of these amps...Marshall was experimenting with things like quot;headroom,tightness,gain,and crunch early on with their amps to try to keep up with what musicians wanted..

Maybe Jeff Seal can chime in? Trace Allen has taught me an awful lot about Marshalls,especially the early NVM series and the 800 series! I own one of Trace's 50 watt heads also...
Don't get me wrong John..no doubt a 1987X with a bunch of new parts and stuff isn't likely to nail the best tones of the original 1987's out there. I just mean that a reissue with some work will def put ya hella close compared to any quot;modernquot; marshall (i.e. DSL/TSL, etc)..for thos who cannot afford an original and desire classic Marshall tone.

Trace knows his poop on Marshalls for sure


Originally Posted by JeffBDon't get me wrong John..no doubt a 1987X with a bunch of new parts and stuff isn't likely to nail the best tones of the original 1987's out there. I just mean that a reissue with some work will def put ya hella close compared to any quot;modernquot; marshall (i.e. DSL/TSL, etc)..for thos who cannot afford an original and desire classic Marshall tone.

Trace knows his poop on Marshalls for sure

Yep....


Originally Posted by JeffBWhile this is true...I'd have to agree with Shred..cos most people really are misinformed and refer to old NMVs as plexis...just like everyone calls a Tremelo a Trem...when a Vibrato is the correct terminology...

yup - that's what I meant, it's not a generic term amongst people who take a particular interest in amps, but it seems to be among many people I've come across that don't.

There's not a great deal of difference between an early 70's metal panel and a '69 plexi circuit wise, if you're wanting to convert something metal panel spec to a plexi spec, have a go at making it a 12000 series (late '67/early'68) amp, that's where the tone's really at if you're into EVH sounds, but also just a fantastic rock amp. The components in 12000 series plexis vary quite a lot as they were very much transitional amps (evolving into the '69 and later circuit), so don't get too hung up on what values are right as you may find different parts in every 12000 series plexi you see. Have a go with these values:

v1a: 820ohm/330uF
v1b: 2.7k carbon comp/.68uF
0.022uF for both channels signal caps
470k/250pf mixer combination on channel 1
v2: 1.1k carbon comp/.68uF or 330uF bypass cap
56k tone stack resistor
16uF 16uF preamp filtering
100pF ceramic cap and .1uF signal caps at the phase inverter

and have a go at switching them around a bit to get the sound you're after. Those are what I've modded my 1959slp to and it sounds FANTASTIC. Worlds apart from the stock amp, it's now the perfect rock amp, I love it!


Originally Posted by shredaholicyup - that's what I meant, it's not a generic term amongst people who take a particular interest in amps, but it seems to be among many people I've come across that don't.

There's not a great deal of difference between an early 70's metal panel and a '69 plexi circuit wise, if you're wanting to convert something metal panel spec to a plexi spec, have a go at making it a 12000 series (late '67/early'68) amp, that's where the tone's really at if you're into EVH sounds, but also just a fantastic rock amp. The components in 12000 series plexis vary quite a lot as they were very much transitional amps (evolving into the '69 and later circuit), so don't get too hung up on what values are right as you may find different parts in every 12000 series plexi you see. Have a go with these values:

v1a: 820ohm/330uF
v1b: 2.7k carbon comp/.68uF
0.022uF for both channels signal caps
470k/250pf mixer combination on channel 1
v2: 1.1k carbon comp/.68uF or 330uF bypass cap
56k tone stack resistor
16uF 16uF preamp filtering
100pF ceramic cap and .1uF signal caps at the phase inverter

and have a go at switching them around a bit to get the sound you're after. Those are what I've modded my 1959slp to and it sounds FANTASTIC. Worlds apart from the stock amp, it's now the perfect rock amp, I love it!

What alot of people didn't realize and what was lost in some of the tone of the earlier series,was these small changes..The removal of the .68 cathode cap for instance at V2 was an effort to actually take some gain away from their preamp.That .68 cap on V2(switchable on my amp)actually adds gain..Those V1 values also varied but realize those values only would effect that channel if you were to plug just into only one channel and not jumping channels..The transformer voltages probably had more overall effect on both power,crunch,and feel than the other changes,but it's the overall combination of things working together that made the early series great..Marshalls early amps were a continuing transistion of things while they tryed to please the players of the day...Their amps were evolving..Personally I don't hear a difference between the use of .022 and the .0022 they used in the early stuff....I just always use .022 in both values..The filter cap values made a difference in the overall feel and tightness of the amp..

Coupla Plexi Marshalls!

Hey guys, what does the term NMV stand for? That one's eluded me.

John, that photo is SO not fair, LOL. I want a plexi daddy--and I want one NOW!


Originally Posted by 75lespaulHey guys, what does the term NMV stand for? That one's eluded me.

Non-Master Volume


Originally Posted by 75lespaulHey guys, what does the term NMV stand for? That one's eluded me.

John, that photo is SO not fair, LOL. I want a plexi daddy--and I want one NOW!

Those aren't my amps! Just an internet photo I Liked..

Actual PLEXI's refer to the plastic-y / plexiglas panels on the old school Marshalls.

That aside, Marshalls from 1967 - 1973 are handwired BEASTS! They sound unreal! Creamy, huge, angry, and toneful - tons of articulation, very warm, and very responsive to touch. They are also louder than hell! After 1974 they slowly got brighter and brighter, then mastervolume models came in and voila you had the brighter 80s metal crunch which Slash and Lynch exemplify

Listen to any Allman Bros, Van Halen, Live ZEP, Free etc and its a 100w Plexi