Marshall JMP-1

Marshall JMP-1

  • Like
  • Tweet
  • Pin it
  • Submit

JMP-1, Guitar amplification from Marshall.

35 user reviews

Marshall JMP-1 tech. sheet

  • Manufacturer: Marshall
  • Model: JMP-1
  • Category: Guitar amplification
  • Added in our database on: 09/06/2003

The Marshall JMP-1 is a four-channel valve MIDI preamp that spans the Marshall sounds from old-school cleans to DSL Roar.


Marshall JMP-1 user reviews

Average Score:4.5( 4.5/5 based on 35 reviews )
 24 reviews69 %
 5 reviews14 %
 2 reviews6 %
 1 user review3 %
 1 user review3 %
Audience: Value For Money :

Ddams's review" marshall stereo"

Marshall JMP-1
tubes and unmodified version
balanced jack possible
-20db/+4b switch useful for the studio with stereo output with/without speaker simulator.
I use tc tonerpints in the stereo loop, mix at 6/12
read the different forums regarding the stereo effects loop


as easy as it gets, each channel has treble, middle, bass, bass boost, and presence effect
user's manual????
responds correctly to the pedal
a boost can make the tubes crunch


what kind of music is best suited for the marshall sound?
ibanez sa260fm
epiphone les paul black custom


warm, clean sound, the overdrive is responsive to the knob and the attack, the tubes are present
noise on od1 with the gain at 17/20
used to record in the studio
getting it ready to use it as backline
good value for money, really good, really sturdy
I recommend it highly!

tonejunkie99's review"JMP-1=G System=Marshall 100/100= stereo 4x12 cab"

Marshall JMP-1
we control and use the preamp with a G System, power it with a EL34 marshall 100/100. and run it into a customized stereo 4x12 marshall cab. I mount the 100/100 in a separate rack because I sometimes just carry the preamp out to use with other set-ups. without writing a book, my background is 25 years of playing in working bands, and having said that, I was always hard core plexi and really love the sound of superlead stacks. My old school rig was 2 JMP 1/2 stacks. I later went with a wet/dry combination, in other words I send all the effects to one wet/amp and keep the other amp dry. when I went to the wet/dry configuration, we sometimes used a modified JCM-800 head on one of the cabs. anyways long story short, a good friend passed away and he wanted me to have his Rack rig. It literally sat in a corner of the warehouse for 3 years until another guitar player took the covers off the racks to see what was inside and went on and on about how awesome they are and who all uses them still to this day, so we hooked it all up and ran it stereo into 2 4x12 cabs with vintage 30's... literally we all went nuts over this thing... I think anyone who likes marshalls would like the JMP-1 we have had all kinds of preamps over here, and ever since we started using this one, it's really sparked some creativity.


It's the most simple preamp to use I ever seen. very straight forward it has the typical Marshall stuff, Volume, Gain, Bass, Middle, Treble, Presance. It has an effects loop and you can adjust the mix. It has a bass shift. 2 stages of overdrive, and 2 stages of clean. you can save up to 100 presets, and control it with midi... It has no onboard effects.


Most the night it's reissue les pauls through it. I do a switch and play about 5 songs with a 1963 strat. My pickups are hand wound and read around 9k. the strat pickups were rewound by a old man in Dallas Tx named Vanzandt, he passed away around 1999 I believe... anyways I dont use extreemely high output pickups, so these guitars will sound perhaps a little brighter than some. I change the volume pots in les pauls to 500k pots and although the JMP-1 dosent clean up as much as a big plexi, it cleans up enough for me. With the volume knob you can go from a RATT(or worse) type gain down to a "All Right Now" type tone, and 74 Jailbreak would be in there somewhere also. our music is Power Rock, most comparable to 70's 80's. the tones from this rig without effects is straight-up AC/DC sounding, cleaner settings like Free/Bad-Co. If I add a little more gain, chorus and delay it's totally 80's. on clean settings with chorus it sounds kinda like Purple Rain. With a Flanger it sounds kinda like Pat Travers rig or V-H Unchained. with volume knob technique and a-lot of delay set around the high 400m/s range it will Nail the cathedral sound. one issue I have is you loose a lot of db when switching from od to clean settings.


I like the sound of it. it was given to me, but I would hunt one down if I lost this one, I would probably have to pay around $400. to get one used on ebay todays prices. we have had almost every kind of preamp in here you can think of. I like this one because it sounds good and it's simple. It's not loaded with effects and it wont sound like a fender, which is good for us, but not for everyone... if you mounted this JMP-1 in a rack next to a POD the pod would have a depressive meltdown and cut on itself.

racerevlon's review"A great alternative if you don't have $$$ for a JVM!!"

Marshall JMP-1
The JMP-1 is a valve MIDI preamp. Let's break this down into components. Valve: there are two 12AX7/ECC83 valves on-board that help the preamp generate the gain and the classic Marshall sound. MIDI: the preamp is MIDI-controllable in addition to the simple 4-button foot switch and has 100 user preset locations. Preamp: I think this is where most people get confused. This is a preamp ONLY--it still requires a power amp, whether you have a dedicated rack power amp, or you run into the loop return of an amp head, you'll need a way to power this unit. The only exception is if you're using the emulated out to record directly to a console. All of the usual suspects are on-board: Bass, Middle, Treble, Presence controls, a mix for the effects loop, individual buttons to select each channel, and a "Bass Shift" feature that alters the frequency range affected by the tone controls. There are standard mono or stereo output jacks for connecting to a power amp, emulated line out jacks for connecting directly to a recording console, and an effects loop with a -10/+4 button for connecting and controlling the effects loop. All in all, fairly flexible for a 1U valve preamp.


The JMP-1 on its own is only half of the equation. I've heard a JMP-1 sound absolutely atrocious through one type of power amp, then absolutely magical through another type of power amp. You have to keep in mind what's down-stream of the JMP-1 to ensure you get the best sound out of the preamp. Historically, the selection dial on most of the earlier units was "jumpy" and didn't track very well, something I heard Marshall fixed in later releases. The preamp is simple enough to use if you spend five minutes playing around with the controls and learning what every control does. Saving MIDI parameters is simple enough, requiring only a double-press of the "Store" button to save a MIDI preset/patch.


I've owned this unit long enough to know that experimenting with different types of tubes DOES make a difference. The best sound I've got from the JMP-1 is using Mesa Russian-2 tubes, which is what I still use today. That said, it's really easy to make the JMP-1 sound horrible. My suggestion, as with many things, is to dial in the JMP-1 with your ears and not your eyes. The B/M/T/P controls range from -6 to +6 but don't set the controls where you "think" they should be, set the controls where they sound the best to your ears. If you find that you get a great sound with the bass set to -6, so be it. Don't let your brain override your ears by thinking, "well, that can't be right--there's no way it could/should sound good with the bass fully cut." It can and it will. Always keep in mind this is a PREAMP, not a full amp. If you like the idea of Marshall's latest offering, the JVM series but don't have the cash, a JMP-1 and a good power amp are an excellent compromise. You get four channels, each with a gain control that ranges from 1-20. Even on the clean channels, you can get some good bluesy crunch if you crank up the gain and have fairly strong valves on-board. The key is that you have to spend time dialing in the sound you're looking for with the JMP-1, again, with your ears, not your eyes, and always be mindful of what you're using for power and speakers. Taking something like the JMP-1 and plugging it into a cheap solid-state power amp with cheap speakers will sound, well, cheap. However, go the other direction and run the JMP-1 into a nice valve power amp like a Marshall EL34 50/50 or 100/100, VHT 2/90/2, or even a Mesa 20/20, and you'll get MUCH better results. I run my JMP-1 into a Marshall EL84 20/20 and can get so many great sounds out of it that I actually sold my JVM410H. Just like a pedal/stomp-box, the JMP-1 is ONE piece of a larger puzzle.


The JMP-1 is incredibly flexible and puts a ton of different tones right at your fingertips. You can go from Jazzy clean to death metal with almost no effort. Now that they're out of production and prices are way down, I think the JMP-1 is an excellent value for the price, especially considering that the emulated line out, while sounding "slightly" what I would describe as "transistor-y" is still absolutely viable if you're recording on a budget. I've also owned an ADA MP-1 and would say that they're two different beasts. The JMP-1 interface is much easier to master, but the MP-1 has the on-board light chorus effect that really punctuates the 80's rock sound. Being a rack unit, it's somewhat of a pain to experiment with different tubes but once you find the sound you like you're good to go. Many modern players/bands (Iron Maiden, Def Leppard, Billy Gibbons, etc.) still use the JMP-1 as a staple of their live tone due to its MIDI-switching capability and its virtual warehouse of almost the entire Marshall tonal history. If something were to happen to mine I would replace it without hesitation.

Hyde's review

Marshall JMP-1
Everything or almost everything has been said already. No need to add much, except that mine (bought secondhand to an AF user) has two jj tubes and came with the pedal that goes with the jmp1.


The configuration couldn't be easier. Personally, I connect it to the return of my fallen angel head.
"Is it easy to get the right sound?": oh yes!!! Especially since everything is configurable on the jmp1: clean sound, distortion sound, bass, mid, treble, presence, effects loop level, gain, volume.
Regarding the patches available, 26 are already preset by the manufacturer but they can be modified at will. All others are entirely free for you to create your own sound.
The manual is simple enough to be easily understood by anyone. A table details the 26 preset patches (volume level, gain level, bass level...).


Connected to the loop of my fallen angel, I have tested the jmp1 with my 3 guitars: an American strat, a gibson les paul smartwood and a ltd viper tuned one semitone down.
I "reproach" my fallen angel for having a too sharp, too solid, too modern sound. I want heavier sounds, so that's why I chose the marshall over the engl 530 or the voodoo valve. And I was not disappointed, on the contrary. For people who love rock, in every sens of the word (poop rock, hard rock, heavy metal), this preamp is for you. The sound palette is such that it's impossible not to find the sound, or sounds, you are looking for. I haven't had it that long to be able to really exploit all the resources of this beast.
For those who think you can't get a big and fat sound with the jmp1, I can guarantee you that you are wrong: with an EQ (mxr 108) in the loop, even an overdrive to boost everything (mxr wylde or ibanez tube screamer), and the possibility to adjust all parameters, we can go from a superb crunch to a very nasty and fat sound (maybe the jj tubes have something to do with that? I haven't tested it with the original tubes, so I can't confirm that).
It's true that the jmp1 isn't the best for clean sounds, but it wasn't made for that. Nevertheless, with a bit of reverb and a compressor we can get very nice results.
Finally, something that came as a really nice surprise to me is that it is possible to get fat distortions at low volumes with this preamp. I suddenly have no use for my vhm power break anymore, which was indispensable before (I've put it up for sale).


My opinion might be very subjective, given my little experience with amplifiers, but the jmp1 truly corresponds to the sound I was looking for and that I like so much. You may criticize the marshall sound, but nevertheless it has something and it's part of rock history. The jmp1 has reconciled me with marshall because I was very disappointed after trying out a tsl 60 combo which paled against the fallen angel.
I highly recommend this preamp given its great value for money, especially secondhand, if it's in good condition, like mine (thank you aliascross!!!).
What I like best is the diversity of sounds and their configurability (is that even a word?)
What I like least: maybe the fact that you only have four sounds available with the footswitch (but then again, a midi pedal will help you easily get round that problem).

Edit from 01.06.07: after several days I changed my jmp1 for another preamp (an engl tube toner). But it wasn't because I was disappointed by the jmp1, but rather that I had no use for one of the preamp's main advantages: the configuration possibilities it offers. The jmp1 requires a lot of time to fine tune the sound, which is something I don't have. That's why I took the opportunity to change it for a tube toner that has more basic settings and is easier to configure. I still think that the jmp1 is a very good product, and who knows I might end up coming back to it someday...?

Marshall JMP-1 images

  • Marshall JMP-1
  • Marshall JMP-1
  • Marshall JMP-1
  • Marshall JMP-1

Marshall JMP-1 videos

Marshall JMP-1 manuals and other files

Discover other products!

Other names: jmp1, jmp 1, jmp1

Cookies help us improve performance, enhance user experience and deliver our services. By using our services, you agree to our use of cookies. Find out more.