Metropoulos Forum

I just picked up a 1980 JMP 2104. The amp is in great condition and mostly stock. Electrolytics have been replaced, the IEC receptacle, and one coupling cap.

I've been trying to find details on the jmp circuit to see if I've got the right value coupling caps for v1. I know some marshalls have 22n in both positions, and some marshalls have 2n2 for v1B and 22n for v1A. Could anyone tell me what the correct value for v1B should be for my amp? It's the one coupling cap that's non-original. I've seen schematics say 22n for this position but I'm also aware that marshall would change parts a lot of times, so I'm a bit unsure.

Thanks!

2.2n in every amp i have seen. Since Marshall was known to use both, either value would be considered correct I suppose. I would start with 2.2n and if the amp doesn't have enough beef and thickness to the tone, swap in a 22n and see what you think.

It's got a 22n in there now, so next time I open it up I'll play around. Gotta reconnect the bright cap and see how I like that too. Right now it sounds really good, but a little undefined so that 2.2nf might tighten it up in the right ways for me.

Thanks for the insight!

I apologize but I mispoke. I meant to say that 22nf was the value that I have always seen in this circuit. I was thinking about the nmv circuit when i typed 2.2nf.

Hi, if you haven't found the answer yet, I think you can go to our website https://www.oemstron.com/ to make a consultation, there are professional customer service to help you solve any problem you have.