Which model for a late 70s JMP master volume style?

[Random Hero]

The Brit 800? I was thinking Plexi 2204 but from memory it sounds a little dark for what I’m thinking so more along the lines of the Brit 800?

The early 800s were basically rehoused JMPs, right? And the Brit 800 model is an early example of the 2204 if I remember correctly.

As a reference -

 

[muudrock]

I recently dug my 79 JMP out of storage and I had forgotten how much I love that amp. What gets me super close to mine is: 2204 model, change the preamp tone stack type to 800. Apply some low cut via the input eq (114-140) and/or the engage the cut switch. I also keep the bass control 5 or less. Play around with different preamp tube types-I prefer the Sylvania. A lot of these came stock with 6550s as well so try switching to those. Another thing I do is raise the Transformer Match up some. Keep the preamp gain below 7.5 and master volume above 5 for best results. Season to taste with a good greenback IR. To my amp it's really close.

 

[marshall2553]

Plexi 2204 should be the closest to a JMP. But since there were circuit changes and component value inconsistencies from amp to amp, it may not sound like exactly like you’re expecting. If it sounds too dark, bump the bright cap value up. IIRC the 2204 has less gain than the 800, maybe the model was based on one of the early JMPs before they cascaded the inputs. A higher bright cap value would also help with that. Or just use the Brit 800 if it gets you closer to what you want out of the box.

 

[York Audio]

The Brit 800 sounds nearly identical to my ‘77 JMP Master Volume. I just set the power tube type to 6550 and that’s it.

 

[LiamH]

The Brit 800 sounds nearly identical to my ‘77 JMP Master Volume. I just set the power tube type to 6550 and that’s it.

Same for my '80 (so very late) JMP MV 2203, and my (now sold) '77 JMP MV 2203. Both on EL34s for me in the real amp, so that's how they stay in the AFX III model. The model is very sensitive to cab IR used on the settings I use. The real amp is very sensitive to the cab used in real life. Who'd of thunk it?

Neither model nor real amp sound very good unless you keep the master volume up above 3.5, which is pretty deafening in the case of the real amp. But in a good way.

Liam

 

[muudrock]

Brit 800 and/or the 2204 with 800 tone stack will get you there. Clip is a quick tweak of the 2204 model with 800 tone stack. Stuck a 57 on a GB in Marshall 4x12. No eq. It's a lot brighter than I would like, but it sounds close to the video. It's also super close to my 79.

Marshall 2204 AFIII