Now for the part with controverse. Don't complain it doesn't sound like a tube amp when you use it with a solid state power amp made for hi-fi and some crap cab for audio with a 15" for bass and 12" for highs. Of course it will sound like shit. I've tried.
Get a real setup, all tube with good cabs before dissing the JMP-1.
Ibanez RG1570L (Dimarzio X2N and The Breed Neck and EMG AB)
Epiphone Sheraton II---->JMP-1--->Loop--MXR 10-Band EQ-- Peavey Valverb-->Output to Mesa 50/50 moded with bias and KT88 on one side--> through Two Mesa 1X12 Recto Cabs (two is essential since one sounds too small and a 2X12 sounds thin compared to those).
I'm a Jazz player, and ex-Metal player.
The EQ is flexible, but there is some mid-mid peak that makes it sound vintage a little too much, that needs to be removed with an outboard EQ. Tube swapping helps a bit. JJ's ECC83S make the amp too dark. EH are taming a bit the mids and give better note definition.
Clean 1- One word: Dark. Even for Jazz it's way too dark.
Clean 2- Great clean channel. People who say it's too bright have something stuck in the ears or don't know how to set a clean channel.
If you put presence on 6, well of course it sound overly bright.
The trick is to adjust it in the right way, and not to over EQ as you'll loose balance and tone. My settings are: Vol:20 Gain:12
Bass:0 Mid:-2 Treb:4 Pres:-6 With proper guitar it will give a great vintage sound with articulation and complex mids if combined with proper units (tube reverb, etc). Gain is tricky on this channel.
Over 14-16 you loose balance in sound, too much bass and less highs.
8 was giving good sound but lacked definition/articulation. 12 was the best compromise. On those settings the clean has a strong bass,
you can make the air swirl when playing complex chords. I was surprised to get such a great jazz clean on a JMP-1. Was hard to set, but I now have a WEs Montgomery or Grant Green tone.
OD-1: This is a hardcore channel. It gets the Marshall Name.
Raw, roaring brutal sound you hear from old Marshall heads. Very trebly, middy, with tight shy bass. With an EQ adding a bit of bass you can make hte sound thicker. Great getting that half-distortion sound, harder than overdrive, but that tone where you still hear the string's tone. Great rock tone or metal rythm. Now for the lack of gain people complain about, well I'll tell you the JMP-1 has enough.
One day you'll understand that having a shitload of gain is only compressing the sound to a point where you loose tone and dynamics, which are essential to get a heavy tone, because if you play heavy, you'll sound heavy. Not a matter of gain, but of a big sound and technique.
OD-2: Ass-kickin channel. Smoother treble (can be restored to crisp through an EQ), strong mids and huge bass (without the Bass booster which boosts way too much bass). This channel has a more compressed tone with gain over 16-17, which is good for lead. For thich chords, run gain at 16-17 and you'll see that you have great definition on this amp. I have tried many EQ settings with this channel, and found the only way to make it sound goor is to scoop the mids. It restores balance. Thick sound, great for heavy rythm, but less grinding. Kind of a compromise to have more gain.
The MIX button SUCKS TONE!! Beware.
Output must be set high, with lower volume, to drive the tubes.
Very tubish feeling, great dynamics on clean2 and OD-1.
Not very versatile since once you'll find your sound you'll find no other one on the unit. It is possible to get dark jazz clean, sparkling pop clean, raw distortion, thick distortion, screaming lead or soft lead. Besides that, hard to get. The on-the-edge of breaking up clean is hard to get, bad for blues. But OD-1 is great for blues. For distortion, the amp sounds extremly brutal in tone, and leaves gain low enough to play heavy. A good example of heavy playing with lower gain is the song Blackwater Park from OPETH.
You can get that tone easily.
It's old, but in mint shape. Only the power button is partly broken.
Stupid idea to use a push-pull thing instead of the traditionnal switch that doesn't break.
Marshall stuff usualy is easily breaking, the knobs especally. But this unit doesn't have those damn knobs whose solder always break and makes the sound cut when turning the knob. Only two knobs. The output is a traditionnal knob, and was dusty, but I didn't even need contact cleaner (I bought because I had a Marshall head before and I needed A LOT of contact cleaner to keep it usable). The one knob you always use feels strong, and isn't giving me trouble.
Those small buttons to edit parameters are great instead of usual knobs. And unless you're poking them real hard with a pen or something sharp they don't break. Under smart use the amp lasts. I say that because there's really dumb players out there. They manage to drop bear inside a Mesa Quad preamp, to break all the knobs because they are stupid metal heads.
Under normal use: Very dependable. More than Marshall stuff. 9.
Under dumb brute use: might break, but slower than amps with tons of knobs to bang when you're too drunk to turn them slowly. 8
I would gig anytime with the JMP-1, in any gigs. I would just put my rackmount somewhere out of reach of stupid people. Jazz gigs no problem, but metal gigs I would be careful.
It is a great piece of gear. I won't go for a small tube combo for Jazz since I have a great vintage clean. Very toneful amp.
Don't let the controverse fool you. It sounds very organic and real.
On it's own, it is a little weak, but when in a real setup it's great. Get some decent reverb, power amp and cabs.
I don't fear somebody stealing it since my rack is damn too heavy. The thief wouldn't be able to lift it up the stairs.