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Marshall JMP-1 Tube MIDI Guitar Preamp

Sound Quality

All Rock styles played. I use a Schecter Hollywood custom with Seth Lover pickups, a G-Major effects rack and a Behringer footpedal to control both. I put the whole thing through a 2020 El84 Marshall valve amp and a Marshall 2 x 12. IT ROCKS. When I get the orignal greenbacks (sitting in my attic) into the Cab I am sure it will be awesome. I also have an 80-80 valve state as a live back up but it really sucks through that and I hope I never have to use it. Have recently revalved the whole rack (after chatting to Derek at Watford Valves) and fitted a clean valve to the clean channels and a Groove tube mullard reissue to the distorted channels. Clean is so good now, clean, lively full bodied and excellent clarity. Distorted is excellent with more sustain than Lesley West and a good crunch sound for Rythmn. I am still in the process of setting it all up and getting the clean/distorted/rythm/lead balances right. However, even at 40 Watts total output (I would say that is in reality "nominal") and I can still cut it in a really loud band without any effort with power amp on 50%. Not massively noisy, but you need a noise gate in high gain. Gives loads of Marshall sounds a lower volumes. OK it will never match the full marshall stack at "number 11" on the vol. but what do you want!!!!!! It gets a 9 cos I don't give 10s


Never gone wrong on me But to get the best, you need to look after it a little. Make sure you got room in the rack for cooling. Use a valve power amp and again leaver it space to get rid of the heat. Will improve lifetme and reliability.

General Comments

Been playing longer than I care to think about, more than 1/4 century, mainly as bass. Always played guitar but last two years solely guitar.

Technically competent, electronics and hardware. Service my own gear.

Input on the back only thing missing.

Noted the problem mentioned with the data input where it skips a couple of digits. Turn it slow and it's OK. Suspect some switch debouncing needed.


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