I play PRS Cust.22 / pedal fx / Monster Cable chords (chords are under-rated for sound quality - get good chords) / Marshall el34 50/50 poweramp / Peavey 4x12 cabs.
First off, it sounds really great. OD channels have some noise in some setting, but then so do the OD and gain channels of tube amps. If the noise seems excessive, and you're sure it's from the JMP-1, ne tubes can do wonders - others in the forum give some good advice on tube selection. The Volumes on this seem to be true volumes and don't change the tonal characteristics of the sound (very cool). As others say,, this is a Marshall and gets a distinctly Marshall sound. It's sounds are very close to other Marshall amps, but I'd say it has a sound distinct of it's own, which is a good thing.
Gets cool thumping Marshall High Gain sounds, Great Classic Rock Sounds, Poor for Blues sounds (although a good OD pedal with mild breakup sounds great over the cleans in this). The cleans have alot of tonal variety, but I wish the gain in the clean modes would add a touch of growl or breakup when set high (when it does, it's not very smooth to my ears). I personally feel if you want a great blues or jazz sound, buy a tube combo amp.
A WORD ON TONE: This is just a preamp. Tonal breakdown:
10% Pre-amp (including tubes in preamp)
10% Power amp/Cabinet (especially the tubes and speakers)
10% Gear (Guitar, pedals, chords, strings, picks, etc.)
70% YOU (Technique, ability, attitude, soul, love for music)
Clapton will still sound like Clapton if he's playing a Silvertone guitar through a Gorilla 10 watt amp - maybe not EXACTLY what we've come to expect, but still Clapton.
Every sound has tone, some good, some not, but that is in the ear of the beholder. Find a sound you love and play it til you find another one you like better then play that one, and the rest of the world be damned. If you're in love with your sound, you'll play more, and the tone that is you will grow. (Sounds like fortune cookie cheese, but it's still true).
So far so good.
It's a keeper for what it does. Idealy, I'd also have a Mesa Triaxis, Vox AC30, and a Fender Twin. Someday. This is a great tool. But bear in mind, it's only as good as everything else that goes into it. I've also owned digital units (POD, Digitech, ART) and this is not digitally generated sound, it lacks the high end chime,ring or whine of digital sounds. Also owned Mesa, Peavey and Fender amps, and this is as good as any I've owned - like the others, it has it's own sound.