1978 Marshall 2203 Photo Dump

Goober23

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I have the exact same amp in near mint condition too! It is truly an excellent tone machine.
After seeing this post I plugged into it and wailed it into my Two Notes and through a pair of panned 4x12 ir's
Boy do I LOVE that amp with my trusty Les Paul Classic! Those old 2203's are an example of excellence in amp design and manufacture.
Kind of a high water mark for that era in guitar amps. That tone they put out is just amazing.
 

67mike

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Great amp!

Quick question: is it recommended to rub penetrating oil on the chasis to combat oxidization? Because my 1983 2203 has some on the chasis.

Thanks
 

Derrick111

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Great amp!

Quick question: is it recommended to rub penetrating oil on the chasis to combat oxidization? Because my 1983 2203 has some on the chasis.

Thanks

No it is not recommended. It is not necessary, but if you do so, be very mindful of getting it on tube sockets because that could cause all kinds of funky noise or arching issues. You also would want to avoid the area around the paper assembly label. It wouldn't take much to saturate the any paper labels with oil. It is not something that is needed though and you likely just end up attracting dust/dirt that falls on it over time. There is already a protective coating on these chassis, even if they don't always look shiny and pretty. Marshall JMPs aren't show cars with chromed parts.
 

AlvisX

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My '76 has mustards . One thing I didn't remember to look at was the brite and / or peak cap values & make when I was tweakin it ......or if the early ones had peak caps (I believe they did , but I can't remember) I find them to be the REAL culprit , not the brite cap.
Anyway they surely did in the JCM's ,why I find most of em not useable for my tastes , unless those values get tuned up a bit

 

GregM

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Showing interest .
Very nice guy shots . It would remind me of when I had abs except , I never had abs ....
Wake up dear Mutley your dreaming again , your not robin hood and your not Gungedin , your not a brave knight or a king that been crowned , your just plain old Mutley , the snickering hound .
 

Goober23

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Also I think '78 is the year "The magic happened". By way of the way the gain stages were designed. The Previous
JMP's were different and had less gain I think. From '78 on they were true JCM-800's whereas before that they were more
"Plexi-ish?
Nothin' wrong with a plexi mind you!
 

Derrick111

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Also I think '78 is the year "The magic happened". By way of the way the gain stages were designed. The Previous
JMP's were different and had less gain I think. From '78 on they were true JCM-800's whereas before that they were more
"Plexi-ish?

I wouldn't go starting that rumor ;-) There was no major change from '77 to '78. Last year, I compared every component in one of each, side by side, and the only difference were the values of the cap and resistor on the presence pot. As I recall, the voltages are the same as well. Regardless, both amps scream. My friend's '80 JMP doesn't sound any less "70s JMP" than a '77. I have an '81 JCM800 and you would be hard pressed to tell the difference in it from a late 70s JMP. The changes in tone should be much more gradual over time if still in stock form.
 

Goober23

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I wouldn't go starting that rumor ;-) There was no major change from '77 to '78. Last year, I compared every component in one of each, side by side, and the only difference were the values of the cap and resistor on the presence pot. As I recall, the voltages are the same as well. Regardless, both amps scream. My friend's '80 JMP doesn't sound any less "70s JMP" than a '77. I have an '81 JCM800 and you would be hard pressed to tell the difference in it from a late 70s JMP. The changes in tone should be much more gradual over time if still in stock form.
I had an '82 50 watt 2x12" combo version and it too ROCKED! I'm one of those that also think the later 1980's JCM-800s (though I never could bond with my 2210) not the channel switchers were amazing and maybe even better than the 1970s versions as I kind of liked the sound of the less filtering capacitors in the power stage. I do think that starting in '78 Marshall started to cascade gain stages in the MK-IIs and this was the "birth" of the JCM-800 sound we all know and love.
 

V-man

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Also I think '78 is the year "The magic happened". By way of the way the gain stages were designed. The Previous
JMP's were different and had less gain I think. From '78 on they were true JCM-800's whereas before that they were more
"Plexi-ish?
Nothin' wrong with a plexi mind you!
The truth in that rumor applies to 2204s as they did not have the cascade gain mod until @ mid-77 and don’t sound very good before then. 2203s started with it.
 

V-man

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No it is not recommended. It is not necessary, but if you do so, be very mindful of getting it on tube sockets because that could cause all kinds of funky noise or arching issues. You also would want to avoid the area around the paper assembly label. It wouldn't take much to saturate the any paper labels with oil. It is not something that is needed though and you likely just end up attracting dust/dirt that falls on it over time. There is already a protective coating on these chassis, even if they don't always look shiny and pretty. Marshall JMPs aren't show cars with chromed parts.
I would not disagree with this for the most part. The operation for me was about getting something that removed the dull textured residue that accumulated on the surfaces over the years/decades (after hand dusting with a small paintbrush). Lubrication was sprayed on a paper towel, not on the surface and it was wiped dry, avoiding all sticker areas. I am fairly convinced the accumulated surface crud does every bit as much to trap dust/humidity and aid in corrosion than a carful wipe every 5-10 years might. (The principle of lubricating a gun bore “properly” vs leaving the gunshot residue to accumulate moisture).
 

Smellytele

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Fellow 78 2203 owner (pretty new to me still). I absolutely love mine. It's kinda a crazy story how it came to me, which I've already shared a while back. Mine did have to have the PT replaced, but the OT is all original and it didn't look as though any major mods had been done to it, though it had been converted for 6550's, which I had reverted back to el34's. I'll see if I can find my gut shots and do some comparing with yours.

Sound wise, it's just fantastic. I've had a chance to compare it to a few 800's and one 77 2204 and this one I've got has some extra mojo going on. I keep using the word "rich" to describe it. Not in a monetary sense, but in a textile sense. Thick, warm, round, aggressive, and beautiful. Sheesh, I gotta stop huffing gasoline before I get online, I get all deep and shit.

Anyway, that is a beautiful amp you've got there, love and cherish it.
 

V-man

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My '76 has mustards . One thing I didn't remember to look at was the brite and / or peak cap values & make when I was tweakin it ......or if the early ones had peak caps (I believe they did , but I can't remember) I find them to be the REAL culprit , not the brite cap.
Anyway they surely did in the JCM's ,why I find most of em not useable for my tastes , unless those values get tuned up a bit


I missed this post at first and am rather shocked you have mustard legos on a ’76 as I recently saw a ‘78 that barely had any on it (thinking it was a transitional model where they were getting rid of old components. The inconsistency of these builds (not withstanding the circuit being otherwise =) is practically a misguided form of art in its own right!
 

Derrick111

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I think he means round axial Philips mustard caps, but he can chime in to confirm. I wasn't going to comment, but "mustard" caps doesn't apply to block caps that are yellow. I think that's where the confusion comes from. Mustard and yellow block caps are not one in the same. Your caps are yellow block caps. AlvisX's caps are probably axial mustard caps unless changed to yellow block caps later on. Black caps didn't show up in Marshalls until about 1978, with the exception of some tan ones (I forget the brand), and axial ones by Wima, and some other yellow axial caps found largely in 1972 examples. It gets confusing to read, but seeing enough chassis from the 70s and it all begins to make clear sense.
 

Deftone

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FWIW, I was just playing my new to me '79 JMP 2204 & my '85 JCM800 2204. I run them in stereo and A/B them to compare. Very similar tone though the JCM is going through G12-T75's and the JMP is through V30's. They sound the closest (and the best) to my ears with these speakers. The JCM through V30's was too bright, IMHO.

The JMP just sounds better. I don't know the proper terminology, but it the note separation is more defined, and it's clearer if that makes any sense. I liked my SL-X better than my JCM800 2204 but the JMP just sounds better than anything else I have ever played.
 

V-man

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I think he means round axial Philips mustard caps, but he can chime in to confirm. I wasn't going to comment, but "mustard" caps doesn't apply to block caps that are yellow. I think that's where the confusion comes from. Mustard and yellow block caps are not one in the same. Your caps are yellow block caps. AlvisX's caps are probably axial mustard caps unless changed to yellow block caps later on. Black caps didn't show up in Marshalls until about 1978, with the exception of some tan ones (I forget the brand), and axial ones by Wima, and some other yellow axial caps found largely in 1972 examples. It gets confusing to read, but seeing enough chassis from the 70s and it all begins to make clear sense.
That would make much more sense to me and of course “mustard caps” generally refers to your illustrated example, which is why I always use the term “legos” (and there wasn’t yellow ”shit” until the 80s with all those goofy ‘burnt’ hues back then).
 

Derrick111

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FWIW, I was just playing my new to me '79 JMP 2204 & my '85 JCM800 2204. I run them in stereo and A/B them to compare. Very similar tone though the JCM is going through G12-T75's and the JMP is through V30's. They sound the closest (and the best) to my ears with these speakers. The JCM through V30's was too bright, IMHO.

The JMP just sounds better. I don't know the proper terminology, but it the note separation is more defined, and it's clearer if that makes any sense. I liked my SL-X better than my JCM800 2204 but the JMP just sounds better than anything else I have ever played.
Were you doing a low volume, or a high volume "cranked" comparison? I ask because JCM800s become completely different "animals" ...and I do mean animals when cranked. We used to kick the JCM800s out of our way in the used music stores to get to the JMPs before we knew the secret (was so simple too)... just crank the JCM800s to make them come alive. That was when they started going from $400 used to $1k and up... Everyone was using them at low volumes in their bedrooms and in moderate practice volumes. They weren't into the sound. A low volume JCM can sound thin, fizzy, and one dimensional. I laymen terms, tell people this happens more so for JCMs rather than JMPs because of what makes the JCM that much more of an animal when cranked (the higher voltages and more treble to keep things clear when roaring). The JCM800 is simply not a low volume amp as the master volume would imply. And by low volume, I mean below about 4 or 5 on the volume. It's face melting at that point on the volume dial where there is pretty much no more volume left to go, just more saturation. You just don't get that perfection in hi gain amps or JMPs... the JCM800s are a unique mix of the old with the most aggressive new before high gain territory.

A real eye opener I do for friends in my studio to demonstrate this is to put in some earplugs, hit a chord on the guitar, and slowly turn the volume up from 0 to 10 on the JCM800, noting a thin sound changing to one with the "body" kicking in around 3 or 4 on the dial, continuing to get bigger and bigger until you get to a point where you are just adding more distortion/saturation (approximately 7-10 on the dial). Then I go back to the 1 or 2 that most play them on, and then go to 5 or 7 and show the difference in sound (not just volume). The difference in how they usually set the volume vs how it sounds above 4 or so is a real revelation. A comment I hear most often is how modeling doesn't capture the sonic harmonic magical swirling force of a cranked tube amp, though they have done a pretty good job on the distortion part itself. I also hear how it's too loud for some, but there are attenuates, and the key is to not go overboard with one and use a good one.

One more side tangent... people have dissed the G12-75 for years in the same way (being too thin and fizzy). I found that they are PERFECT for a cranked JCM800!! They "wake up" with cranked JCM volumes, and the treble response evens out and fills in with a blaring JCM. The newer ones made in China, I can't comment on, but the original ones form the 80s seem to be the ones that work great with JCMs and that's what I have... not later ones. I use the 75s from the 1980s over my greenbacks and black backs for JCMs, but I also use the early 80s 65s which are also so great for a bit more "rounder" sound! When recording, I usually use 75s panned to one side, and 65s panned to another. Great mix of aggressive presence and warm rounded bliss, respectively.
 
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Derrick111

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That would make much more sense to me and of course “mustard caps” generally refers to your illustrated example, which is why I always use the term “legos” (and there wasn’t yellow ”shit” until the 80s with all those goofy ‘burnt’ hues back then).

I find the caps used in JCM800s to be quite good. The issue can be, as @AlvisX noted earlier on, is the treble peaking that increased over the decade (much more so than the decrease in filtering). Here is an '84 with yellow block signal caps:

MARSHALL_JCM800_2203_04.jpg
 

V-man

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I find the caps used in JCM800s to be quite good. The issue can be, as @AlvisX noted earlier on, is the treble peaking that increased over the decade (much more so than the decrease in filtering). Here is an '84 with yellow block signal caps:

View attachment 113175
That looks crazy to me as well. I thought they started stabilizing by the JCM era and 79 JMPs forward all seemed to be hosting Cherry Legos from what I have seen.
 

Derrick111

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That looks crazy to me as well. I thought they started stabilizing by the JCM era and 79 JMPs forward all seemed to be hosting Cherry Legos from what I have seen.
The brand of caps used were pretty consistently in flux between 1976 and 1986. The "chery leggos" you are reffering to were red Iskra block caps which came in around some time in '79 and were gone by about 1984. They went back to using at least some yellow Philips black caps like those used around 1978 with a mix of others... As I mentioned, I don't really feel like there is a big difference in the various brands, but there shouldn't be. They are all just polyester caps assembled in a plastic box shaped body with epoxy to seal them form moisture. By 1987, they were pretty much all white block caps after that.
 

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