Spite Build - Marshall JCM 800 2204

[Greg_L]

Well alright, I'm calling the Assman a success and as that exercise in clusterfuckery was going on I was secretly compiling parts for this thing.

This will be a pretty faithful Marshall JCM 800 2204. A 50 watt EL34 Marshall master volume amp. I admit, this is a spite amp. This is bitter revenge and anger. I found one of these for sale recently and the guy wouldn't deal with me so I said "Fuck you I will build my own". And that's exactly what is gonna happen. And it will cost about a quarter of what the guy was asking for the other one. And it will be perfect.

So here it is. All the parts are here.


Pots, switches, jacks, knobs, etc.


Caps, resistors, nuts and bolts


Big ol honkin power transformer, output transformer, and choke. Mucho power.


Chassis and "Plexi" faceplates. This will be a 2204 - a 50w master vol amp - but the chassis could also be used for a Plexi. There is very little difference between the two.


So that's it. I have a bunch of Marshalls already, and I even have a late 70s JMP era 2204, but not a JCM 800 2204. And now I will. Let a new game begin.

[Tadpui]

Awesome, the Spite Build

May I recommend green tolex and gold piping? Hehehe.

[Greg_L]

Awesome, the Spite Build

May I recommend green tolex and gold piping? Hehehe.

Haha if I was doing tolex for this project I'd absolutely consider it. I love the dark green and gold Marshall look.

But I already have a traditional normal headbox for it.

Actually....I ordered a proper JMP style headbox for my JMP 2204 which is currently in an incorrect Plexi style headbox. So this spite build will get that incorrect Plexi-style headbox I already have and the JMP 2204 I already have will get the new JMP-style headbox. Got all that?

[vomitHatSteve]

Hilarious!

Bonus points if you can incorporate blackjack and hookers into the name

[Tadpui]

Hilarious!

Bonus points if you can incorporate blackjack and hookers into the name

LOL I just watched that episode last week, I've always loved that line.

That and Urectum have maintained a place in my head for all these years now.

[Greg_L]

I don't think I've ever watched a second of that show ever.

[Bill L]

I can't wait to see this unfold.

[rayc]

Do it in Black n red and call it the Spiteder.

[JD01]

Don't you already have a JCM 800? I thought it was your main amp.

[Greg_L]

I can't wait to see this unfold.

Do it in Black n red and call it the Spiteder.

Haha clever but black and red are colors I don't voluntarily go with if I can help it. It's a football thing. Black and red are the colors of my Saints arch enemies. I won't even say their name.

Don't you already have a JCM 800? I thought it was your main amp.

I do, and it is, and I already have a 2204 too. But I don't have a JCM 800 2204.

[JD01]

I do, and it is, and I already have a 2204 too. But I don't have a JCM 800 2204.

Right, now you've stumped me. I have no idea what you're talking about.

[Greg_L]

Right, now you've stumped me. I have no idea what you're talking about.

When Marshall finally developed their master volume amps in 1976, they had two circuits:
2203 = 100 watt master volume
2204 = 50w master volume
The amps are virtually identical except for the filtering and output stage. The 2203 has more B+ filtering and obviously twice the power. The preamps are identical.

My current JCM 800 is a 2203.
My current 2204 is a JMP. The JMP 2204 came to life in 1976 and eventually became the JCM 800. The JMP era 2203s/2204s are generally a little "softer" than the later JCM versions due to their slightly lower internal voltages.

So while I do have a JCM 800, and I do have a 2204, I do not have a JCM 800 2204.

The "JCM 800" name actually does not mean much of anything at all. There were many Marshalls with the JCM 800 label. But when guys are just sitting around talking gear and someone mentions "JCM 800", they usually mean a 2203 or 2204. Those were the kings of the lineup and the ones pretty much everyone would want.

[JD01]

OK, I think that makes sense.

[Greg_L]

OK, I think that makes sense.

The introduction of the "JCM 800" name and appearance in 1981 was largely just a cosmetic change. A 1980 JMP 2204 and a 1981 JCM 800 2204 is the exact same amp just in different clothes.

JMP 2204



JCM 800 2204



They are the same amp.


But one crucial and generally unintentional difference that just happens to coincide with the cosmetic changeover is that Marshall also went with different power transformers around the same time they changed the look of the 2203/2204. I can't remember if they ran out or changed vendors or whatever, but around the time the JCM 800 look came to be, they also got beefier transformers. These higher power transformers give the JCM 800 era 2203/2204 amps a little more grunt and edge than the earlier JMP versions.

[JD01]

So, short version. You're making a 50W version of your JCM 800?

[Greg_L]

So, short version. You're making a 50W version of your JCM 800?

Yup.

Or a "JCM 800" version of my 2204.


And....with this not being a valuable vintage actual Marshall, and with it being turret board construction, I can relatively easily mod and tweak this thing all I want.

I may add an fx loop. I may add another gain stage. Who knows? I might just leave it alone! I do ultimately have hopes and dreams for this being my main live gigging workhorse.

[Greg_L]

Okay and away we go.

Just bolting on the external shit. Transformers, tube sockets, filter caps. This stuff is heavy, and it needs to be very very secure.






For anyone that saw the filter cap explanation on my Assman build, those blue cans on this one are the filter caps. They're different from the individual caps I had in the Assman, but they do the same thing which is filter the high B+ voltage. These are mutli-section filter caps. They're two in one. Each can has two 50uf capacitors inside of it and they're rated at 500 volts. This is the Marshall way of doing it, and it works fine, but it is not as good as the Fender way. The problem is each of those can caps only has one shared ground lug, so you can't easily separate the grounds like you can on a Fender. I'll touch on this more later. For now they're in.

And one of the big things that separates this 50w 2204 from the 100w 2203 are these filter caps. This 50w model has three can caps. No big deal. The 100w models have six! That's an expensive load of capacitors.

[rayc]

A good read.

[WhiskeyJack]

Shitdude i am sorry I somehow missed this entirely. Good on you. Keep it going. this will be good practice for my 20Watter i mentioned to you one time!!

Are you taking any liberties to make it your own on this one?

[Greg_L]

Shitdude i am sorry I somehow missed this entirely. Good on you. Keep it going. this will be good practice for my 20Watter i mentioned to you one time!!

Are you taking any liberties to make it your own on this one?

No not really. Not for tone anyway. This one will be faithful to a true 2204 circuit. I think the Marshall 2203/2204 amps are the best amps ever made by anyone ever. I cannot improve on what I already think is perfection. I'm just hoping to get it right. I will be improving the grounding scheme though. These amps can be noisy. Marshall's method of grounding this circuit is not good. It can be better, and I'll definitely do that.

Later on down the line maybe I'll do some experimenting with gain characteristics and stuff, but for now it's just gonna be a stock 2204.