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Marshall JMP-1 Tube MIDI Guitar Preamp

Sound Quality

American '92 strat with custom Tom Anderson single/single/humbucker config and phase switch capability. A vintage'78 Ibanez ES-335 Artist w/ factory PAF style humbuckers, and a chimey '72 Tele with a PAF in the neck and phase-switchable custom humbucker in the bridge for single-coil twang or Pete Townsend like grit. It doesn't do everything, but, what it can do it does very well. For those who can't get good tone, or are concerned that it doesn't sound similar to a Mesa or Vox(EL-84)or clean as a Fender, be conscientious of what kind of tonality you are looking for and expect the Marshall palette of sounds, then sculpt your tone accordingly. I play Brit-Pop to Alt-Rock. You can also get some great bluesy Keith Richards like grind as well as some chimey U2/Edge-like tones. I would use this for any gigging cover/original band situation where 60's thru 90's rock is played and I can also play serious funk and R&B with this rig, the cleans are THAT good. If you prefer the compressed spank of Nile Rodgers or some old school Prince/Sly & The family tone you can get it with the right guitar, pickup, effect selection. But, you have to use your instrument volume/tone in tandem with the parameters on the amp. Match up the right cab(s). I've had luck with two Mesa/Boogie 1x12 cabs in stereo; one thiele closed back custom Boogie/Celestion, and the other half-open back EV 200-watt 1x12 for the funky cleans. But, I have since found a Marshall birch 2x12 with Vintage 30's which sounded a little more robust and earthier. I've become a minimalist and run the effect mix on the pre-amp at a low level(3-5)any more and you start to lose the round warm tonal quality. I use two TC Electronic pedals and a racked reverb/delay unit. I don't like to string too many boxes or rack units within the effects chain, I feel I lose precious direct tone whether it's through the effects loop or in front of this particular preamp. I approach the unit like a channel-switching head but, rack mounted mand with 2 extra channels. My power amp is switchable in wattage from 50 to 25 watts a side. I will rate it a 9 for two reasons; There is a noisy hiss in the high-gain CH2 area which can be annoying at high volume. Also, tweaking mid/bass/treble levels on the fly during a gig gets tricky which can sometimes result in accidently saving over a favorite parameter or changing a characteristic you otherwise shouldn't have, by pushing the wrong button on a dark stage. Aside of that this preamp looks classy, is an outstanding value and overall rocks!!


110% dependable. I feel the early JMP-1's were made very well. It has stood the test of 10 years. I've changed the 12AX7's once with Groove Tubes. Volume pot is a little scratchy but has seen 100's of gigs and everytime without a backup. Mine has paid for itself in spades on it's reliability alone.

General Comments

I've been playing/singing seriously for 18 years.

I'm a singer-songwriter with my own project studio in L.A.

If it were stolen, I'd probably look into a different tonal palette. I'm into sheer simplicity at the moment, boutique tone without the cost for a one-trick pony. Possibly a Deluxe reverb w/blackface upgrades or a Vox 60/120 watt modeling head w/matching 2x12 Celestion Blue cab.


I love that the Marshall JMP-1 has the Plexi grind and cleans up very round and warm..it's different than a Boogie, not like a Vox or Fender, but, like a real Marshall.

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