Identifying a Marshall amp

[ampgeek]

A friend of a friend is interested in replicating an amp that he used and loved back in "the day". Unfortunately he can't remember the model number.

Oh...the ravages of an ill spent youth!!

Any chance that the low res picture below sparks a recollection/familiarity with anyone?

I am guessing that we are talking late 70's to early 80's but I am not entirely sure on that.

TIA,
Dave O.

[Gibsonman63]

Obviously a JMP. Why not build a 50W super lead and tweak to taste? Things are not always exactly as we remember them.

[ampgeek]

Thank you!

I am not yet sure of the goals of the project but appreciate the advice.

Thanks again,
Dave O.

[Reeltarded]

Fawn. Get the gun.

[wyatt]

It's a JMP 2203 (100 watt) or 2204 (50 watt). You're friend should be able to remember at least 50 or 100-watt. He may remember it saying something like said "Master Model 50w Lead" or "Master Model 100w Superlead" on the back.

Lots of 2203/2204 schematics and layouts on the web. The amo would eventually get a facelift and become the JCm 800, but because the JMP versions share the same chassis, head cab, iron, etc. with the traditional 4-hole JMP's, it's the popular way for Marshall cloners to offer the JCM800 circuits without having to stock JCM 800 head cabs and chassis.

The only major variation is the earliest Master models, a la '75 or '76, they didn't share the extra gain stage of the late '70's JMPs and '80 JCM 800's.

[ampgeek]

LOL! Funny you should say that. I had already named it Bambi in the back of my mind!

All kidding aside, was that a fairly common covering for the JMP series?

The owner is an American so I am assuming that it had the Unicord perscribed 6550 output tubes. Is that a fairly safe assumption?

Arghh...I am so behind the curve on Marshall amp history. My "ill spent youth" centered around Ampegs for some unknown reason.

Thanks again,
Dave O.

[ampgeek]

Thanks Wyatt! Very helpful info there as I was just starting to scratch my head a bit.

The first JMP 50W schematic that I pulled up must have been from a very early model as you suggest. It didn't cascade the lo/hi inputs. The first JMP 100W schematic that I pulled up did cascade the channels ala JCM.

Cheers,
Dave O.

[wyatt]

Fawn, Red, White, etc. weren't uncommon, but they were less common than Black and usually command a higher price (not that it matters anymore).

I would figure an American-bought model probably came stock with 6500's, but if it came down from Canada, it probably had EL34 or maybe even 6CA7 stock.

[thejaf]

Typically the 100-watters had a vent grill on top behind the strap, and 50-watters did not. Your friend should remember that.

If I'm not mistaken, the non-cascades master volume was only around circa 1975, and did not come in the later 70's style head case (as shown), rather it used the early 70's styling.

So, follow 2203 or 2204 info and you should have a good starting point. I had a 1978 2203 for a few years, decent enough after a few subtle mods (new caps, switched to EL34s, and minor resistance value changes) but eventually sold because I wasn't using it a whole lot.

[Gibsonman63]

I have a '79 2203 running 34's. It is one of my better sounding Marshall amps, but if I was building one, I would go for the 2204. The 2203 has plenty of power and then some. It takes a bit of volume to get into the sweet spot.

[Reeltarded]

Most of these will be 77-79 in fawn. More 100w combos than anything else.

Can of black paint is only a buck. That's what we used to say.

[ampgeek]

Thanks for all the great input mates!

Based on the feedback from the original owner, it sounds like it was a later model JMP 2204, 50W utilizing 6550 power tubes.

Thanks again,
Dave O.

[BIG Dave]

Look what I picked up off Craigslist a few months ago! Model 2204, Master Volume, 50 watts.

[img:640:426]http://www.TheSlipperySnakes.com/pics/2204FRONT.jpg[/img]

[img:640:426]http://www.TheSlipperySnakes.com/pics/2204BOARD.jpg[/img]

[Reeltarded]

Fun!!

[ampgeek]

NICE! Looks like an excellent score.

Any guess as to the year of manufacture?

6550 output tubes?

Thanks for sharing,
Dave O.