I will be honest and say that I didn't like the Vintage Modern because to me, it does not sound like a vintage Marshall. It's nothing to do with its responsiveness or dynamics, or my playing ability - I'm quite used to playing JTM45s, JMP 1987s, Super Leads, 2203s, Jubilees etc and getting great ton...

Might this have anything to do with the dropping of the valve failure fuses between JCM900 and JCM2000? Since it was possible to deliberately pull one of the fuseholders on the 100s to run the amp on two valves...

You've removed the mains fuse, so it's not surprising the amp doesn't work! DO NOT use the fuse from the mains socket to replace the HT fuse, even if you then replace the mains fuse as well - it's the wrong value and will seriously reduce the protection afforded by having separate fusing. Put the ma...

Excellent! I definitely believe that resistors should not be used as fuses. If a part of a circuit needs protecting by something blowing, it needs a proper fuse. Fuses are intended to fail safely, whereas resistors aren't and can cause serious and difficult to repair board damage as you know! - or e...

It's probably blown the HT fuse as well. The one I just worked on with a valve failure had also damaged the cathode bias-reference resistor (R83 - there's the equivalent R84 for the other half of the output section as well). The resistor had charred but not blown entirely, so the amp was still worki...

DeanM - yes, of course I've thought about that! I've even done something similar, a long time ago using a previously-hacked 4-channel JMP PA head. (It sounded great, but it didn't have onboard switching - I don't remember exactly why I sold it now either!) I've also thought about getting a couple of...

SteveD - I haven't totally written you off! Or the Vintage Modern. That's exactly why I'm asking what I'm asking... it doesn't sound at all like what I'd want, but I can see (I think) the potential in the schematic for it to be much closer. What I want is a '68 JMP50 and a '76 2203 somehow magically...

surfnorthwest - yes, you're right, this is the 50W version (combo), as was the other one I heard. Interesting observation about the 100W model, I'll wait until I hear one. I did run it through my usual favourite cabinet too, to make sure it wasn't just the speakers. (It wasn't.) bluezguy - my ears a...

Hello! Quite a long post for my first one here, so I'll give a little background. I've been playing and working on vintage Marshalls, and working on modern ones professionally as well as all types of other amps, for over twenty years. I've owned several nice vintage ones and restored dozens to origi...