Marshall JMP-1 Tube Pre-Amp

For editting patches, this is one of the easiest pieces of gear I've owned. All peramitors are accessable with dedicated push buttons. No drill down menues, multimode keys. A brief perusal of the manual maybe necesary to familiarise yourself with the level options, jacks. More reading if you're gonna be using a MIDI controller.

Here I can only really talk about the sound through the speaker emulated outs. Alas, not being a pro or regularly gigging musician, I can't justify buying a power amp and cab. I'd never be able to crank it in my small urban flat anyway.

So that said. The speaker emulation outs go straight into my soundcard. I play Ibanez RG321, Ibanez JS-1000 or a Fender strat, into a Carl martin Compressor / Limiter. As others say. This is pure Marshall. If you want Mesa, Engl etc go there. If you want any of the Marshall tones from across the years, there in here. I mainly tend to use the OD2 with gain backed down. Either for a mid rangie Iorn Maiden sort of sound. Or more of a scooped chuggy rythem tone. For clean, I tend to stick with the second clean channel for it's brighter sound. Not as sparkley as a Fender of course. But Fender don't do crunch and distortion like this.

I'm shortly going to change the valves for the first time. Noticing some fizz and microphony now.


7 as it's Marshall tone through and through. May not be versitile enough for some.

Backup not an option really. If I were gigging it, I'm fairly confident it would stand up. Racked in a 4 U flight case at home. It's never glitched, broke or failed after 5 years regular use. It was second hand when i bought it. Minor scratches on the metal casing and a small chip off the headphone jack. Superficial stuff.

9. But bare in mind, not been lugged around in vans.

Emailed Marshall once about changeing valves. They responded pretty quickly. Couldn't really ask more.

Other gear I own / have owned.
A Digitech GFX Twin Tube: Nice sound. Awkward to edit quickly. Didn't do the Marshall sound.

Marshall Valvestate VSR 100r combo: Use if in a band.

Johnson J-Station: A quality piece of gear, stupidly discontinued. Again though, doesn't cut the Marshall sound for me. Use for practise and the Fender Twin model.

Damage Control Demonizer: Bought to have a different sounding tube driven, direct recording solution. More Mesa than Marshall. No preset storing.

Over all the JMP-1 is for me, an essential bit of gear. I play stuff from clean surfy , through to industrial, old school metal, blues, post rock instrumental... Anything I can really.

Were it stolen, I'd be most vexed. I'd certainly get another.

Nothing gets a 10.

Nobody can go wrong with this amp. Just one knob.

I have a rack midi setup. I love this amp. I can hear a sound in my head that I like and with this amp you can dial it in. There is no sound that you cannot make with this amp. The possibilities are insane. The only sound that I cant greate is the sound of a fuzz. You need a pedal for that. All distortion and clean tones are in the box. And you can safe 100 presets.

Not much to say. It is an all-valve preamp. digitally controlled.

I would actually give 11. I play in two bands and solo pop act and a metal band. For each band I have my presets loaded to everysound and every different guitar I use. So each song has 1-2 or maybe 3 presets and they are eq'ed for that guitar I use for that song.

Single rack space twin tube / digital preamp . Lots of basic Marshall goodness along with an effects loop / D.I. outputs . Simple to operate and edit. The manual is clear and easy to read.

Well here we are in 2009 and this piece of gear i still find to be very valuable and effective. I bought mine used and obtained it in very near mint condition in 2004 - it has been serving me well ever since. I have an eight space Grundorf cab loaded with a Mesa Boogie 20/20 power amp - the JMP-1 - TC M300 - BBE 482i - Furman power conditioner. Let me first clarify that the addition of the BBE or EQ relative equivilint is mucho needed to acquire the very best tones you can create using the JMP-1 ... it's simply a must have. As a stand alone unit without the addition of added EQ or Aural enhancing , the resident tones are a bit dull and lifeless. For my own needs the BBE works a great singular magic adding spank and life back to the tone. I use a Lopo 2x12 cab loaded with a pair of WGS ET-65 speakers to run it all in stereo. I love these speakers! Read my review of them here at HC. Okay , now for the details. You really have to twiddle with the various parameter settings to bring this thing to it's best offerings. There's a lot of hidden treasure in these units just waiting to be unearthed. You'll read other reviews knocking the effects loop - don't believe it! The effects loop in particular is probably the most careful parameter settings to make per patch. There's a range of 0 to 12 resident to the effects loop. The key is to get your effect from your unit dialed in first (all its parameters) and then to balance the input / output ratio using the range control on the JMP-1. Each patch according to the effect being used will yield a different range value - that's the deal. You've heard about the cleans not being too clean - forget about it! Again, the BBE brings the clean and the sheen into the mix. The trick is to twiddle the EQ and especially the gain settings resident to the JMP-1. I have dialed up a beautiful assortment of clean tones - my faves include a bit-o-grit when rolled up at the guitar volume and then fades out rolling down the guitar volume. The resident distortion patches on the JMP-1 are generally dark sounding to my ears - but again , the BBE changes all that. I really dig the variance of grit to grind to shred i can dial up with this unit. For my own taste , i don't use a gain setting over 15 even though a total value of 20 is available. I also use a pedalboard equipped with various dirt boxes and phase,chorus, and delay units that i send straight into the front end of the unit to get further tonal options. When using the pedalboard dirt tones i use a clean patch i created within the JMP-1. Don't use dirt boxes into the front end feeding a distortion patch - things can get out of control at that point and you'll find that you just end up wrecking a better dirt tone resident to the unit along with a lot of unwanted noise. I have found that the JMP-1 is a great versatile tone shaping preamp - with just a little added help. Of course , your power amp and speakers are the final stamp on your sound so be mindful of that. I forgot to mention up top that i use the Rolls Midi Buddy to make patch changes to the JMP-1 and TC M300 - there's a bit of latency between the switching but i myself can tolerate it as i don't do a lot of constant real time patch switching during a tune - moving from verse to chorus to solo patches has been just fine even though the lag is present as a very micro blip in time. It's no wonder these units have regained some popularity as more and more players are rediscovering the hidden riches these beauties hold. I can't think of a more fundamental preamp to be without ... the JMP-1 is a must have in my opinion.

Got mine used in 2004 and have had no issues with it whatsoever.

For myself , the JMP-1 is my choice as the go-to rack preamp. It allows me to cover a lot of stylistic tonal soundscape. You must use something like the BBE or equivilint to get the best out of it. I use a McCarty, Strat , Tele , SG , and JEM through it - each with great success. The pups on my Strat and Tele are humcancelling i should point out. I've been playing since my teens and i am ... well, a classic rock age player to say the least. What i like most about the JMP-1 is its one space configuration and flexibility and its famous heritage tones we all cut our teeth upon at some time or another. I tried other preamps and i won't name them out of respect for others who may like that product - but for me , the JMP-1 fits my needs best while yielding a variety of useful tones with careful editing.

The first thing I have to say is that this is the second JMP1 I have owned over the years. I sold my original one when I left rack based setups and went for heads and combos but I have always missed this unit and my decision to get another one after all these years says all I need to say about how good they are. Cost me a lot more to replace than I sold it for so it seems that they are becoming quite rare these days.

Its a pretty simple unit to get into but it would be a lot easier if it was all done with knobs instead of patches but then it wouldnt fit into a 1u would it? The midi functions are a little complicated and getting it to switch channels on your effects when you change channels on the MPM4E footswitch had a fairly wide learning curve. But other than that, its pretty simple.

The sounds available here are nothing short of excellent. Both clean feel as they were lifted right out of the normal and trebble inputs from my jtm45 all at lower volume. At high gain, the drive channels remind me of the harmonic rich slash tone from the use your illusions albums. At low gain, you get everything from nice calm blues tone through to crunchy rhythm.

I use my JMP1 almost exclusevely for live shows and rehearsals where it gets hooked up to a Marshall JTM45 with a TC G-Sharp. The versatility of the patch system allows you to program everything from eq, volume, gain and channel selection to how much of effects loop is incorporated into the mix. Combine this with the fact that you can get the MPM4E footswitch to directly access any of the first 4 patches and automatically change the patch on your effects unit and you are left with an EXTREMELY versatile live setup.

Excellent. Have never had a problem with any marshall units I have owned.

I popped in to their Milton Keynes head office here in the UK to have my 2 JTM45 heads serviced and the service is excellent.

I see a lot of arguements about diodes and valves and to be honest, i dont really care, its the tone that counts. I CAN say that I have removed the br3 and other diode (to do an upgrade) and the clean is 100% unaffected which means that at least the cleans are all valve. The od channels still have the same gain but they lack the harmonic detail and clarity especially at low gain where they sound positively terrible. So yes, it does have diodes in the od channels but they are there to smooth things out and shape the overall sound, they are NOT the main part of the distortion.

Overall, I would recommend thet JMP1 to anyone looking for a live ready preamp with traditional Marshall tone. If you alreay have one and you are thinking of selling,... dont... you WILL miss it!

This actually a very simple unit to use. Utlimately it has 4 channels and the tweaking never really gets confusing. It acts ultimately like the front end of nearly any Marshall amp being that it has Treble, Mid, Bass, Presence. It has a bass "boost" feature which I found very useful to round out solo patches.

I am using a massive rig which includes a Mesa Triaxis, the JMP-1 and lately I have been using the Tech 21 Character series Liverpool as a preamp direclty to my 2:90...I have already raved about the Liverpool but only if you use it like a preamp. I am using a GCX Audio switcher to control the preamps and my pedals which are racked in my rig. I gig pretty regularly so I use 2 1x12 Boogie cabs loaded with the old school Black Shadows for stereo and then mic'd. OK...soo here is the deal on the JMP-1: I really had lowered expectations because I have been using the Triaxis for around 20 years now and have really liked it a lot. The JMP is Marshall to the core..it really gets those tight focused gritty distortion tones. It acts and reacts like a Marshall. I can dial in some great classic tones i.e. Malcolm Young or the blistering metal tones of Rhoades, Priest etc....The harmonic content is massive. This is something that I have admired about the Boogie but the Marshall is actually much more active in this area. If you like to chug and squeel...the Marshall actually makes it much easier to do. The distortions sound natural and not spikey at the top end. On most amps the first thing I end up doing is turn the treble down! This preamp runs at flat or just under flat at the highs and is very smooth. The mid contorl is a little crazy though...I find that I flatten it out or drop it just below center to get that old familiar Marshall tone. The bass control is responsive and focused but can muddy up on the OD channels if not careful. The Presence control is pretty useful. It does exactly what it is supposed to do...move things a little more to the front via high end curve. It's very effective but you have to keep an eye on for fear of spikey tones. The bass boost feature can get crazy too but it really does round things out for solos. I am gonna use the Marshall as my ryth for the harder edged stuff that my band does and stick to the Triaxis for solos. The clean channels on the Marshall are useful but to tell you the truth I will probably stick to the Boogie for clean tones too....but the jury is still out on that one. If you are looking for a good midi preamp..this IS one of them. I am so glad I bought this and wish I would have done it years ago. It is very nice to have the full pallet of Boogie and Marshall sounds at my feet and it really does give you the essence of the Marshall history time and time again. I give it a 9 because an EQ would have been nicer.

Don't know yet...just bought it a few weeks ago.

No idea at all yet

I am in a cover band that plays rock music a little more to the 70's and 80's harder edged stuff. Authentic tones have always been very important to me and this is why a midi preamp has been so useful for me. I have been playing for more than 30 years and own a TON of gear. It this were lost or stolen, I would replace it right away. I do wish it had a 5 band eq so I simply added and MXR through the loop to make that happen. This unit has allowed me to replicate some much wanted tones including Judas Priest, Iron Maiden, Randy Rhoades, EVH and even great medium tones like Rick Nielson, Cult, Journey etc.....You can get a pretty good deal on these now days too so there is really no reason not to get a GCX switcher and start mixing preamps up! Much easier than carrying a half ton of amps with you!!

Takes awhile to get used to. If you can take a day off work, set it aside and monkey with it for a day. The learning curve is probably about 4-6 hours which equals 3-5 days depending on how much you play and how busy you are. I found a very usable tone on all volume levels within a week, and you can usually call it a good friend within 2-3 months.

Not your typical easy-peazy amp head though, so I'll rate it a 7.

Okay. Enough is enough. The Marshall JMP-1 is a stellar unit. If you cannot get a usable tone out of it, you either aren't using it right, you don't have the right gear, or you have tin ears. So, assuming you're thinking about buying this thing, I will proceed to give you a decent user guide :

After you've purchased your Marshall JMP-1, find a good TUBE power amp. Some acceptable ones include VHT, Marshall, and Mesa/Boogie; the last choice being the best mate for this preamp. (I use a Mesa 50/50 but a 2:90 or any other class A or class A/B will work great; in fact 6L6 amps tend to sound thicker and bigger over EL34s)

Replace the old tubes with some new ones that are preferably matched.

Next, find yourself a decently built and assembled 4x12. Peavey makes some good cabinets, Mesa is decent, and so is Marshall. I was blessed and found a Crate 4x12 that sounds very very good. Don't know what it's made out of or what the speakers are, but it's HUGE.

Now, after you've hooked everything up, there's a button on the back of the JMP-1 under the Master that says "Level" with two push options "+4dB" or "-20dB". Select the "-20dB" (this puts less feed on the your preamp and as a result draws more horsepower from your power amp). Now, use the setting on your power amp that draws the most power from your tubes (on my Mesa 50/50 it's a simple Hi-pwr and Lo-pwr flip switch).

Turn your amp on, mess with your settings. If you want a huge, heavy rock/metal type of sound, push the Bass Boost button "ON" and then adjust the bass accordingly. After a few moments, you'll see what I mean and you'll abandon your computer to go play with your newly acquired rig.

If you follow these instructions I'm almost positive you won't be disappointed in this thing. There's a reason I say a 4x12 and there's an even bigger reason I say a quality tube power amp.

All of this should cost you roughly anywhere from $900-$1700 (including the JMP-1).

This thing has a habit of losing screws, washers, and knobs. I've seen many JMP-1's that have cosmetic defects and things missing... these units are not put together very firmly, but I would definitely trust it for gigs and studio use. What's a few missing washers?

If you can follow my instructions above, the JMP-1 more than likely will not disappoint you. I say this because I have played several amps and setups with numerous guitars and the only thing that comes close is Orange and they run at least $2k just for the head. Certain Strats will sound good through this (it really depends on how heavy it is and the phase of the pickups, weird I know) but the real shine is with humbuckers or over-wound single coils. Right now I'm using a Telecaster with a hot single coil bridge pickup and it gives me the crunch of a humbucker but the sparkle of a Tele. Les Pauls and SG's are good matches for this.

This amp has hundreds of possible settings if you look hard enough. The presence knob is a hidden gem that can completely shape the hollowness or the fullness of a tone, and the Bass Shift will get you instantly into metal territory if you are dialed in right. OD1 is a transparent, more JCM800 style distortion; while the OD2 adds another gain stage and gives off a nice furious fuzzy crunch.


All in all a good unit. The minor gripes I have about it are completely superseded by the excellence in tone.


God Bless, Jesus is Lord.

evereything about the JMP-1 is already 100's of times explained so why should Itell more about it,though it's funny to read some posts .

This is my third set since the JMP-1 came out, I started with the JMP-1 and 9100+1960 when it came out.these days I have one simular set but the with eL34 100/100 poweramp,the only thing i dislike is that thare is a little harshness when tones are sustainig (crunch)
it sounds like the solid state circuit is overloading the tube circuit.(it's a hybrid as you know).soundwise it's a good piece to use it for what it is supposed to do MARSHALL SOUND with all the positive and negative issues of Marshall sound.
to me it's one of the nicest preamps NOTE!!!! Not the best ,absolutely not,but it's a preamp great preamp.

with normal use and racked up what could go wrong
seen broken parts on others but never on my gear.

I think it's oke I mailed once and the next day I received an email back

I'm a pro for many years now (30 years of playing)and I'm 36 years old.I play mesa boogie rack sets and used almost all the brands expansive and inexpansive,this Marshall set is a good thing if you use it for what it's made for.a head will sound more organic and these day's they are even are midi (most are) but the JMP-1 +EL34 100/100 +1960A set is a great rack set and it's stereo! with MARSHALL sound not more not less. It gives me a lot of fun!!!!!
and that's afterall what it's all about.......
cheers

The easiest and most versatile midi preamp ever made, that's the JMP-1! If you need the manual for this then you might be a tard and please don't do any reviews. This is a preamp for Marahall users exclusively. This was designed for people who LIKE the Marshall sound. The JMP-1 does not have any Mesa or Fender or whatever sounds in it. It is 100% pure breed Marshall tone.

The JMP-1 sounds like or very very close to just about any Marshall tone out there. Bottom line, if there is a Marshall tone in your head you will find it on the JMP-1. Well, if you know how to tweak those knobs just right. If you use this preamp with only the original 4 button footswitch, you are greatly missing out. This preamp switches via midi. You could for example, set 99 different variations of just OD1 if you were so inclined to do so. Think of it as a 99 channel amp with 4 different voicings. I have owned a Plexi, JCM 800, 900, 6100 LE, Jubilee, valvestate, 9200, DSL 100,etc. If I could only take just one it would be the JMP-1 with a Marshall power amp or head to use as a power amp.

I only have one complaint with the Marshall company. Why don't they stick this JMP-1 in a head box with a tube power amp? It would blow away the new JVM series.

The one thing Marshall should have added to this monster was a contour knob like they have on the old valvestate amps.

The navigation on this piece is well thought out and simple.
Designed for the dedicated Marshall user. Editing is simple, but I can't seem to get away from the old 50 watt non master factory setting. Manual is downloadable and simple.

I use this piece differently that most users in that I use it though the power section of various English Tube Combos. I use PAF, Soapbar, trad Strat and Tele pickups, a Hamer 12 string and an EMG strat through this rig and it sounds great with everything except the 12 string. Can't seem to get a clean enough patch for the 12 string as it smacks the front end pretty hard
The noise level is comperable to the preamp of most amps. If you want trad Marshall tones at any volume...this is the best solution I've found.

I am a little worried about the beating I give it and the cold midwestern nights I've made it withstand in my trunk. But it works.
Luck was on my side, I paid 100 bucks for it because the power switch was broke...never fixed it so it's on all the time when I plug it in. Love to have a backup For a piece that is reasonably complex, I consider it very reliable.

The schematics and manuals for this piece are available on the net.
Marshall is not known for being an accessable company, at least thats been my experience. I think you'd best seek out a good local tech.

More folks should grab one of these and find a nice tube combo amp, access the back end of the amp and find the joyous tones of a nice old Marshall. The front end of the JMP loads and acts like a nice Marshall. When the sound man gripes...and they ALWAYS gripe, you simply turn the preamp output level down. it seems to retain that "guitar plugged straight into a Marshall" relationship at managable volume levels.

Very simple to get a killer sound out of this unit.However there are a few tips I will mention below. Editing patches couldn't be easier.Don't really need the manual unless you are going to do some heavy midi stuff I would guess.

I use the following with the JMP-1 : IBANEZ 7620 and 7621 loaded with DImarzio Tone Zones in the bridge. ROCKTRON INTELLIFEX,DBX 215 EQ or an ALESIS MEQ-230, BBE 482I or 362,midi-mate and a MOSVALVE 500 power amp or Fender 2150 power amp. (I have 2 rigs) Oh yeah I have 2 MARSHALL 1960 4x12 cabs with Celestion gt-75's. The JMP-1 is noisy as most preamps are (exception ROCKTRON)but I use the INTELLIFEX hush for that it's totally quiet. I also use PLANET WAVES CABLES only on them. I don't really try to get other artist sounds but suppose I could if I needed to. OK most units sound better with a SONIC MAXIMIZER on them.This unit in no exception.It enhances the already killer tone but to really nail it in I use the EQ'S mentioned above for that.I have read before that GOOD CABLES ARE VERY IMPORTANT TO GOOD TONE.I have found this to be very true. You will get better clarity with PLANET WAVES,MONSTER CABLES or some other high quality cable. I know most people recommend using a TUBE POWER AMP to get the most out of these units but I get a great sound from my tube wannabe power amps.They are cheaper and don't need re-tubed and weigh less.The 500 WATT MOSVALVE is incredible. Also ditch the tubes in it and get 2 JJ ECC83S tubes for it. It really adds gain,tone and clarity. People who complain about the gain not being enough...you need the other things I've mentioned or something similar.Cleans are ok. The DISTORTION TONE is amazing and I have tried several pre-amps and this one rules them all! 9 out of 10 for just decent clean.

I think it is reliable.No problems yet

Haven't had to deal with them yet.

I play mostly prog-metal with power and thrash tendencies too.This unit along with the other equipment mentioned gives me a very powerful tonefull sound that I absolutely love.I have been playing over 20 years. I would certainly get another if something happened to one.If you are thinking about one...get it. It's a great unit.