Marshall JMP 25w Specialist

[10thTx]

Anybody know anything about this amp or played one?

It's topology is "sort of" an EL34 version of a Princeton Reverb.

There is a poor quality YouTube that shows it has kind of a blues vibe to it
(start listening around :30 into it):

https://www.youtube.com/watch?v=hrTIUVRzby8

With respect, 10thtx

[10thTx]

With the cost of 6GW8 tubes and 6BM8 currently in production and less expensive, I would be inclined to try building this amp this way which would include a 6G9 type fender vibrato/tremolo using a mosfet CF.

When I drew up the layout, I decided to eliminate the .1 cap to ground from pin 7 of the 6BM8. Not sure if it would be needed?

With respect, 10thtx

[deeder]

This amp was one of the very first Marshall with PCB, loaded with one Celestion G15.
Last year I replaced the noisy volume pot on one of these amps. Amazing clean sound, deep and warm that works well when you play a Telecaster for instance. The reverb and trem do both work well, with a good useful speed and depth range on the trem.

If you need some infos about the reverb circuitry maybe you can read this:
https://tubeamparchive.com/viewtopic.ph ... c5307dd767