Plexi vs. JCM800 vs. JMP

[ovid9]

So, school this noob on the difference between Plexi's and JCM800s?

I know the 800 is the successor to the Plexi, but outside of that, what is the tonal difference?

The JCM800 has more gain available and FX loops and...ummm....that's pretty much the extent of my knowledge.

And the JMP is something totally different as well.

I is open for some learning on Marshall maps.

Plox?

[Dave]

Plexi is open with less gain stages. Doesn't compress until its really loud. Also has two parallel channels one being high treble and one being normal. In stock configuration the high treble is really bright and the normal is too dark. People bridge the channels via patch cable and can dial in a perfect balance. Plexis are JMP's. Now, I'm assuming you mean the difference between the plexi panel 60's amps and the 70's metal panel models. The 60's plexis have less distortion and are sweeter sounding for lack of a better term. They're more fender like to me with a rounder bottom end and an open less refined gain structure. The metal panels are more aggressive and more focused with a tighter gain structure. From the JMP's I've tried the differences aren't as pronounced as some would like to believe. Also worth noting the super lead 4 hole JMP's are what I'm referring to here.

The later master volume JMP's retained the small panel tolex front headshell but only have high and low inputs. These have a master obviously and I believe the gain stages are cascaded internally instead of the old 4 hole input where the gain stages ran parallel. The master volume models are known as the 2203. Yes, the same 2203 as the 800 just in different clothes.

Hope this helps!

[Dave]

Oh and the 4 hole JMP's are known as Superleads with model designation 1959 and the later 2 hole MV models are known as Superlead Mk2's.


Basically 4 hole is a 1959, and 2 hole is the 2203. Also, the 800 series also had a 1959 4 hole non master volume model so there is crossover between the different looks. The only circuit that doesn't crossover: there is no 2203 with the small Marshall logo and plexi panel.

[ovid9]

Ok, so the gist is:

Plexi is a version of a JMP, so named for the plexiglass used for the faceplate. There were multiple versions of JMPs.

Superleads are also JMPs, but with 4 inputs.

JCMs came later, some had a MV as did some of the later JMPs.

Do I have the basics?

*I hoped you'd chime in Dave, you seem to have a wealth of Marshall knowledge. *

[ovid9]

Great description as posted, the only thing i'd add is the JMP 2204 & 2203 are called Mark II Master Lead.

also ... 2204 = 50 watt master volume
2203 = 100 watt master volume
1987 = 50 watt non master
1959 = 100 watt non master

Yeah, Marshall's arbitrary assigning numbers as models, but that look like years. Oi. Not so good.

[Rampage]

All I have to say is that I loved my JMP 2203 through G12-65s. Pretty much the sickest rig I have ever owned, but too fucking big and loud for what I need. Now I listen to Larry Carlton and play through a 1x12.

[ovid9]

All I have to say is that I loved my JMP 2203 through G12-65s. Pretty much the sickest rig I have ever owned, but too fucking big and loud for what I need. Now I listen to Larry Carlton and play through a 1x12.

Sorry you had to cut off your balls.

Mojo sent.

[magh8]

don't the JMP's have a lower PV than the jcm's?

[Rampage]

All I have to say is that I loved my JMP 2203 through G12-65s. Pretty much the sickest rig I have ever owned, but too fucking big and loud for what I need. Now I listen to Larry Carlton and play through a 1x12.

Sorry you had to cut off your balls.

Mojo sent.

Meh, they never really got out much so it wasn't much of a loss. Plus I have a ton of time for my arts and crafts now that I don't watch sports.

[ovid9]

Meh, they never really got out much so it wasn't much of a loss. Plus I have a ton of time for my arts and crafts now that I don't watch sports.

This has been an informative thread. Now, if only I could go crank my VTM until my ears bleed.

Sadly, wifey is home and not feeling so good. *sigh*


Whoa, the happy smiley is creepy as hell now!

[ovid9]

I know just what you mean, man. Instead of rawking an old block letter 5150, I'm doing most of my recording now with AMT preamps direct.

And fucking cross-stitch is THE SHIT!

I haven't gone down the AMT rabbit hole....yet. I'm worried if I do I'll end up with a bunch of them for no good reason at all.

[draelyc]

I know just what you mean, man. Instead of rawking an old block letter 5150, I'm doing most of my recording now with AMT preamps direct.

And fucking cross-stitch is THE SHIT!

I haven't gone down the AMT rabbit hole....yet. I'm worried if I do I'll end up with a bunch of them for no good reason at all.

I haven't either, 'cuz I likey my ampsez. So I just bought one of these for recording SILENTLY and late night wankery (that doesn't involve Mrs. Draelyc):


New Dummybox Day!



So stoked ~ gonna be recording my cranked Plexi whilst Mrs. Draelyc & the Draelings snooze away in dreamland! \m/ :ar! :ymparty:

[ovid9]

Ooooh, that is cool draelyc!

My JCM600 has a DI out and I believe it can be done silently (I haven't looked into it a ton yet as I don't have an interface yet) so I'm gonna give it a whirl when I save up the pennies for one.

Me too. I have two, and want at least three more.

That's the only way to do it!

[ovid9]

I thought I was drunk, I can at least do quotes correctly.

Fak!

Why can't we just have a nice normal multi-quote? Why?

[draelyc]

I thought I was drunk, I can at least do quotes correctly.

Fak!

Why can't we just have a nice normal multi-quote? Why?

Because you sit on a park bench, eye-ing little pedals, with bad intent.

[neilrocks25]

I will add one thing, niether had FX loops they come in the RI's

[ovid9]

Because you sit on a park bench, eye-ing little pedals, with bad intent.

dun duh duh....dun duh duh...DAAAAAAAAH

[LES-ZOMBIE]

Jubillee, nuff said!!!!!

[draelyc]

I will add one thing, niether had FX loops they come in the RI's

The later, 2 channel 800s had factory loops in the '80s, right? But yeah, the Plexis/JMPs/single channel 800s definitely did not.

[draelyc]

Because you sit on a park bench, eye-ing little pedals, with bad intent.

dun duh duh....dun duh duh...DAAAAAAAAH

So proud that you got that. You are no longer (and have not been for some time) anyone's resident n00b.

[ovid9]

So proud that you got that. You are no longer (and have not been for some time) anyone's resident n00b.

[100 watt]

Oh and the 4 hole JMP's are known as Superleads with model designation 1959 and the later 2 hole MV models are known as Superlead Mk2's.


Basically 4 hole is a 1959, and 2 hole is the 2203. Also, the 800 series also had a 1959 4 hole non master volume model so there is crossover between the different looks. The only circuit that doesn't crossover: there is no 2203 with the small Marshall logo and plexi panel.

Great description as posted, the only thing i'd add is the JMP 2204 & 2203 are called Mark II Master Lead.

also ... 2204 = 50 watt master volume
2203 = 100 watt master volume
1987 = 50 watt non master
1959 = 100 watt non master

and:

1992=Super bass = 100 watt non master.

there was also a JCM 800 sUperbass, that was a totally different animal than its 60's & 70's predecessors (sp?)

Anyone who likes Marshalls should pick up "the bible". It's a book called the History Of Marshall. Lots of great info. Im assuming you have a copy? good references & interesting facts

[Ry Manchu]

This is what Trace at Voodoo said:

2203/2204 - As a whole the JCM800 line is not all that consistent. There are numerous variances. In direct A/B comparison; Some are noticeably brighter than others, some are more distorted, some have more crunch, other are grainy, etc. For example, the early 2204's ran on lower plate voltage and have more gain than most others. The trade off in this case is in the form is less headroom.

It is true that the very first 2203's were much the same as the JMP Master Volumes however there were not very many of these made, making them hard to find (look for 6 filter caps on top of the chassis verses 3). Generally speaking power supplies varied and filtering varied, IE: later models have V2 and V3 sharing a filter cap with the 47pF on the bias splitter side verses the plate side, etc and so on. The concept with 100 watters used to be (and some still do) put filter caps in series to increase the voltage rating. Generally speaking most do not consider this to be a necessity on 50 watters. Often times the filter caps on the 3 can-cap 2203's are bulging on the top but the 6 can-caps do not suffer from this.

2205/2210's - The dual channel models also have their share of differences. Models made in 1983 have a lot less gain than the later models and usually about the same or less gain than a majority of 2204/2203. There are models in 1984 that also have less gain and a majority of these have red silk screening on the rear panel (models to be imported to Holland, Canada, etc). On some models the clean channel bleeds through on the gain channel. Circa 1985 these models were redesigned to have more gain. The later models had a bit more gain and this occurred circa ‘87/88. On average the models after 1985 do have more gain than a 2204/2203. The models with black silk screening on the back are the same as the later models that followed but the models with red silk screening were identical to the models made in 1983. It should be noted that the dual channel JCM800's gain channel is not the same as the 2204/2203. It is very different in design and as such one does not sound like the other.

Many people crank these amps and use an attenuator, under these conditions the filter caps can easily see voltage spikes past their voltage rating. This is one of the reasons why the older JMP Master Volumes are preferred. IE: the filter caps are rated for 1000VDC verses 500VDC. The bottom end is deeper/richer and the over all dynamics and touch response are much better. The 3 can-cap versions can be modified for the same filtering and we have done it for several years.


This is what Jeff Seal said:

Marshall made the most radical design change on the channel switchers around '86.....(no other amp has undergone such a complete redesign in Marshall history) The early version's have a pretty good clean channel, but the OD is more along the lines of a "*umble", the later versions have IMHO the most killer OD, but the clean(normal) channel isn't particularly clean, but usable.

The 2203/4 had some simple changes made to them, they are essentially the same design. Of course, you have to play through as many as possible to make up your own mind.

Michael Scenker - Early 2205
Tom Morello, Dino Cazares.. (FF) - Late 2205
-------------------------------------------

I would like to add that I believe it was around February to March of 1977 that Marshall began adding an extra cascaded gain stage to the JMP (a simple one wire mod). You can see AC/DC playing these in the Dog Eat Dog live performance from April 3, 1977 and supposedly they received some of the first ones that Marshall made. This was done because people wanted more gain after the addition of the master volume 2203 & 2204 that happened in lat 1975 or early 76. Again around mid-1979 Marshall made another change to the circuit which resulted in more gain. This extra gain had more to do with what people usually describe as the difference between early JMPs and early JCMs. In late 1980 or early 1981 when Marshall's 15 year distribution contract with Rose Morris expired they decided to cosmetically update the whole line to the JCM look.

I have read books on this subject, and somewhere there is a photo of the Marshall parking lot and Jim Marshall had a jaguar with the license plate JCM 800. JMP stands for Jim Marshall Products, JVM stands for James Victoria Marshall, and JTM stands for Jim and Terry Marshall. As for JCM, I've heard it stands for James Charles Marshall or Jim and Clarence Marshall, take your pick. Here is some further reading if you're so inclined:
http://www.solodallas.com/the-vintage-marshall-guide/
http://www.vintageguitar.com/1974/marshall-amplifiers/

[atrox]

You can find 6 cap JCM800 2203's all day. I have one and so does anyone else who has one built before 1984. Trace is off on that one.

[MacaroniSalad]

I've got an early (83) 2210, It has a lot of gain (much more so than I would've expected from an 83). It is on the chopping block however, as its just not as good of a tone to my ear as my AOR is. I really am intrigued by the MV JMPs though, particularly the 2204.

In time...