Marshall 9001 Tube Guitar Preamp

I bought mine new for $600 from MF. At first I thought it sounded more like what I wanted than my old Marshall JCM 800 amp. Running effects into a med gain amp sounds horrible so I was sure this was ok and I sure coul'nt afford spending more. They wanted around $150 for the footswitch so I never did get it. All analog knobs on front so easy to adjust, just that it does not really sound right no matter how I adjusted knobs. I remember opening up top panel and seeing only 3 tubes and alot of miniature electronics and there was that ridiculously loud hummimg transformer that also vibrated alot.

Using humbuckers in strats at the time the sound was ok. I ended up buying a 9005 amp and feeling cheated out of my money. This is not pro gear, it's mid range gear with many issues. Not enough output, too noisy and dry sounding. I favor the Marshall crunch tone, this unit is just a bad memory with alot of solid state crap ruining it for me. Only a Marshall is even worth modding but this unit is all circuit board and is best "sold down the river" friends.

I bought it new and the transformer always hummed and vibrated what I felt was excessive. Marshall released this inferior model and in a few years issued the jmp-1. They forgot all about this piece and did not even offer a foot switch for it after a year. The company sold these junk units and then left us all hang to dry by not even offering a footswitch a year after it was released.

Marshall stood behind the unit, so far back you could'nt see them,lol!

I like my old Kasha Rockmod alot better than my old 9001 preamp. This 9001 always had this thin undertone in it, turns out when Marshall says all tube preamp I don't believe them anymore than the guy selling new stereos out of the back of his van!

This is a pretty straight forward preamp. No scrolling or parameters. Everything is right out front for fine tuning if you need to. Set the EQ and go. Learn to work balance level and gain between R1 and R2 and the R2 voicing and watch how many crazy tones you can get out of this monster.

Ive have used the same preamp and footswitch for over 15 years. Started with a Mesa 50/50 with a stereo bottom loaded with EV 12L. main axe is a 67 Tele. Nothing could touch this set up as far as classic rock crunch and screamin Marshall lead. For you Fender players, tame the high end with the presense control on the power amp or you will shatter the nieghbors glass. Currently using the Marshall through a Traynor YBA w/6CA7 for power section pushing a 2-10 Celestion piggie back. Big sound for a small package. This preamp can cover everything from David Gilmour to Jimmy Page.

15 years and its never let me down. Go easy on the input and output jacks. They are junk. Set it up in the rack and leave the cord connections in. Change the preamp tubes faithfully once a year and this amp will never let you down. I prefer Boogie 12AX7's but thats a personal preference.

Never needed support. I've always maintianed my own gear.

I have two preamp setups each with footswitch and cord. Good luck finding the footswitches for these though they do pop up now and then on Ebay. Ive used Ampegs, Marshalls, Boogies, Hiwatts, and Fenders and would put this side by side with all of them. Not quite a Fender so if your into the Vibrolux sound this may not be for you. The lead section will stomp all over a Boogie and you dont have to spend months finding that sweet spot. For the money thses amps are going for these days its well worth it. You will not be disappointed.

Easy to get basic sounds out of, tricksy when dialing in your unique tone... The EQ section is a bit lame, seems to suck the volume out of it when it's kicked in - best to use a switchable EQ between this and a poweramp. Other than that I have to say I like it a lot :0)

The clean sound depends on what you're putting through it - My main guitar is a Clapton Strat with a Red Lace Sensor in the bridge - I roll off the red a little but the mid and neck pickus give me no problems at all. I also have an 80's Charvel with a Hetfield set of EMGs which sings through the 9001. The Rhythmn channel sounds great, very old school, 60's/70's Marshall tones - again depending on what you're driving it with depends on what you get out. As far as the Lead channel goes I agree with many of the comments previously posted, ie the drive 2 tends to muddy up the sound somewhat. It can be used to create a mean Lo-Fi grunge sound if you drop drive 1 to about 1, but that sound doesn't really appeal to me.

Lead channel, High output pickups on a decent bit of wood = :0p

PS I've loaded it with Harma Cryo valves so it's QUIET on the noise front.

NEver a problem, 200 gigs and counting

N/A

Look, it's a Marshall, very importantly, it's several Marshall's in a box. Use it with a valve power amp or run it into a clean valve amp and you will not go wrong. I've had it straight into a Hiwatt DR201 with a pair of JCM800 cabs and it shook the world. Similiarly through a 9005 poweramp, out to a Boogie cab with greenbacks it really ripped - fantastic tones, clean and dirty. Currently it's going through the 9005 with KT77's for clarity and out to an old Musicman 150 2x12 cab - again going for clarity but it still retains enough of it's own character and warmth that made me interested in the first place. I was after a Jubilee head when I realised that this is basically a Jubilee, Plexi and JCM800 in a box. Nuff Said, does the trick and I won't be getting shot of it.

PS I also have a Mesa Quad, which is difficult to setup, destroys preamp valves if not biased properly and is generally too many things in one box and not flexible enough on the switching front. Yes it's nice, but it's a pain. I'm keeping the Marshall, dropping the quad and getting a 50 Cal+ to keep it simple - and the sound of Boogie IIc+ and Marshall side by side is just Freakin' Awesome!!!

- Controls are pretty straightforward.
- I was able to get very usable tones out of the unit relatively quickly.
- The manual is helpful.

- I use a Jackson Fusion Pro and Les Paul guitars, and a Carvin XV212 tube amp with this preamp.
- The unit is very quiet, even when the Lead channel is used.
- Rhythm channel 1 is too bright for my tastes, and there is no voice (i.e. tone) control for this channel.
- Rhythm channel 2 can provide very good clean or overdriven tones, and has its own voice control.
- The Lead channel combines two different types of overdrives (one rather nasty, the other "brown"), has its own voice and level controls, and can get good AC/DC or Led Zeppelin type sounds, although I find that some EQ is required to tighten low end flab.
- In order to get higher gain type tones (e.g. Gary Moore, Joe Satriani), I found running an overdrive pedal (with tone shaping) in front of the preamp (lead channel) was necessary. With a good overdrive pedal in front of the 9001, I would rate the tone as a 9.
- The 5 band EQ and FX loop work very well. The FX loop can be used as a volume boost by inserting a patch cable from the effects SEND to the RETURN, and then adjusting the SEND/RETURN level controls.
- The cabinet simulator feature is mediocre imho, sounding rather dull, yet buzzy when used as a direct input to a mixer.

- From about 1990 to 1994, I used this unit to play small clubs/bars 1-2 times a month and never had a problem. Since 1994, I've used the unit on and off for recording, and the only issue I've had is that a few of the potentiometers make noise when you turn them (which is not uncommon when pots get old).

- When I was playing clubs, our band played mostly classic rock, so the 9001 was a very good match. It is also a good match for some of the more progressive music I've recorded (again, as long as a good OD pedal is used out in front).
- I've been playing guitar since 1980. Along with the 9001, I have a Tube Screamer with boutique mods, an Alesis Quadraverb GT, a Cry Baby wah, and a Yamaha digital effects processor in my guitar rig.
- If the 9001 were lost or stolen, I'd consider purchasing another if the condition was very good and the price was under $250. Otherwise I'd probably purchase a Crunch Box or OCD pedal.

Its easy to get a sound out of if you follow the manual, or if you just wing it! if you are looking for specific sounds the manual points you in the right direction and after a bit, you can throw it away, it gets pretty intuitive.
manual is pretty good, has all schematics etc....actually it's GREAT!

First off! Everyone complaining about hum or no bottom end...it is your AMP! This one is dead quiet with PLENTY of bottom end and it looks like its been dragged through a ditch for hours.
Don't exactly know why these were a short run (prob. as it's a rack unit...they almost always a shorties...look at the mp1 tube pre, another goody) as they get THE marshall sound if you are after angus, townsend, hendrix....lots of the classics but the clean is VERY good. I play jazz, punk and classic? and it nails them all. I really REALLY liked my mp1 tube pre with a sansamp gt1 through various 4 and single speaker cabs....but this thing just seems to be more real? sounding....more tubey!
Almost like that old special fender champ tubeyness with option of distortion.
My fav. artists aren't the ones listed above...i like sonny sharrock and john mclaughlin...and it does fine getting the majority or their sounds...pretty much better than most any other combination I have tried...PERFEct!

As stated, it has been through hell and still sounds great. Only problem is the main pot is sticky...or slightly difficult to turn when compared to the others, but i never really notice it as it is set and stays there

dunno, never needed it, its pretty cool and all the schematics are free online though

play everything but cannibal corpse? not really, but am amazed at the closeness you can get to srv, evh, zappa and everything in between. WIll not get the death metal sound very well and generally doesn't get a huge variety of clean sounds, but I like and play clean a lot and it does do clean very well.
If you are stuck in the modeling rut, try on of these pups out, really gets back to the roots of rock and crazy jazz....i wish i had the pedal but....doesnt really need it. have owned arion to zoom effects with the best being the sansamp (imho) and an old ibanez tubeking, blues driver was ok, mp1 ok but this thing just kicks it. Have always owned fender, crate,vox and a couple-a ss marshalls but this beats all.

Easy to get clean to 80s metal sounds!

I play 20 years, i own a 1993 MIJ 1954 fender stratocaster reissue; a 1978 greco LesPaul; a handmade Strat with SD SHR-1N&B; a charvel predator 1989; the guitars go to racktuner/9001/tc electronic g-sharp/blues deluxe 1993 model (which goes away for a marshall head).
also i play through a handmade AX84 high octane with a 10k instead of the 820r.

great TRUE SOUND. NOTHING DIGITAL LIKE NOWDAYS LINE6 AND REST OF CRAP!
MARSHALL SOUND, MARSHALL FEEL, MARSHALL ALL OVER EVEN THROUGH A FENDER AMP!

I had another one which I ruing it's traffo one day so I bought a second one.
build like tank to last forever!

good english support!

i play from blues to ballads and then up to doom like metal.. it covers the whole thing!

This pre-amp is very easy to get a very good sound out of it. In the users guide of this pre-amp you can find four sound settings, so it is very easy to get a good sound of it. And also this amp is great for tweaking. You have a lot of possibilities, so you can get many different sounds with this amp. Microsoft Windows is more complexe than this amp ;-) .

I use this amp in combination with Stratocasters (with humbuckers at the bridge position) and Ibanez RG guitars and a Marshall 8008 poweramp and a 4 x 12 inch Marshall cabinet. This gives a extreme good rock sound.
The clean and crunch channel are very quiet. And the lead channel makes very little noise, but that is minimal.
When you put a chorus, flanger or phaser floor pedals (also with the so called expensive vintage floor pedals) between the guitar and this amp I was not impressed by the sound, but when you put a boss half 19 inch chorus flanger or phaser in the effect loop of this amp, the sounds you get are great. And with a 19 inch multi effect processor in the effects loop the sounds you can get are awesome. I use it in combination with a Digitech multi effect processor that has effects like chorus flanger phaser and pitch shifter, so I get the crunch and overdrive sounds out of this Marshall amp(of course ;-) ). Then it is easy to get the sounds of your favorite guitar player.

It is a tank among amps. It never let me down.

I never had contact with Marshall but with their import company and they helped my excellent by giving me a electric scheme so I was able to build a footswitch for this amp myself..

I play mostly rock and hard rock, but also top 40 music.
In combination with a multi effect processor in the effect loop the clean channel gives great sounds. My other amp is a Fender with the famous clean channel o I can compare, but the clean channel of this amp (but in combination with a mfx in the fx-loop) gives very warm and bright sounds.
This amp is really great for rock and hard rock (what did you expect...it's a Marshall)

This pre-amp is very easy to get a very good sound out of it. In the users guide of this pre-amp you can find four sound settings, so it is very easy to get a good sound of it. And also this amp is great for tweaking. You have a lot of possibilities, so you can get many different sounds with this amp. Microsoft Windows is more complexe than this amp ;-) .

I use this amp in combination with Stratocasters (with humbuckers at the bridge position) and Ibanez RG guitars and a Marshall 8008 poweramp and a 4 x 12 inch Marshall cabinet. This gives a extreme good rock sound.
The clean and crunch channel are very quiet. And the lead channel makes very little noise, but that is minimal.
When you put a chorus, flanger or phaser floor pedals (also with the so called expensive vintage floor pedals) between the guitar and this amp I was not impressed by the sound, but when you put a boss half 19 inch chorus flanger or phaser in the effect loop of this amp, the sounds you get are great. And with a 19 inch multi effect processor in the effects loop the sounds you can get are awesome. I use it in combination with a Digitech multi effect processor that has effects like chorus flanger phaser and pitch shifter, so I get the crunch and overdrive sounds out of this Marshall amp(of course ;-) ). Then it is easy to get the sounds of your favorite guitar player.

It is a tank among amps. It never let me down.

I never had contact with Marshall but with their import company and they helped my excellent by giving me a electric scheme so I was able to build a footswitch for this amp myself..

I play mostly rock and hard rock, but also top 40 music.
In combination with a multi effect processor in the effect loop the clean channel gives great sounds. My other amp is a Fender with the famous clean channel o I can compare, but the clean channel of this amp (but in combination with a mfx in the fx-loop) gives very warm and bright sounds.
This amp is really great for rock and hard rock (what did you expect...it's a Marshall)

this is a killer pre amp. if you cant get at least several good sounds out of it,either you cant play,or you have junk to work with.i am SO tired of reading reviews from morons.this is a very simple,easy to use tube pre amp. it is a marshall,and sounds like one.if you want it to sound like "my uncle pee wee's zoom " or a line 6 or any other digital unit you are not going to like it. this pre amp actually sounds great. the cleans are clean and clear, the dirty stuff covers everything from mild to wild.i have read that the bottom end is muddy,well..i dont know what they are doing,but with my 9001,the bottom end it awesome and tight. i use many different guitars with this unit(charvel model 6,gibson sg,ibanez rg760,ibanez rgt42,ect.) i run it into a bgw amp,and 2 marshall 4x12's(i use an art sgx2000 express for any effects ) i have owned many rack units over the years,and this is my favorite .

well,i think i answered all of these questions in the previous box. but to sum it up....this is a great sounding,easy to use pre amp. any guitarist worth his salt should be able to dial in great clean and dirty sounds with very little effort.

my 9001 has never let me down (none of my marshall stuff has ever let me down) i always have a back up EVERYTHING for a gig.its far too easy to plan ahead a bit,and save a ton of trouble.

i have never needed any customer support,but the web site has been helpful

i am a metal/hard rock player that dabbles in jazz,blues,and classical. i have been playing for 20+ years,and have owned tons of guitars and amps/effects. the main point to always remember is that NO guitar,amp,or effect unit will do EVERYTHING for all people. every piece of equiptment has a purpose and limits. pick your stuff because it works for you...not because you hero uses it. and the MOST important piece of equiptment that affects your sound is your hands !

very easy if you know what you want and lean a little how tube amps / preamps are working.

I am mainly boogie player, but still got to say that this is a very good pre amp. you need good tubes and knowing how to make a good guitar sound.
Don't be fooled by some here that don't know how to play or make a good sound. It's good enough for a today guitar player. If you want you can just use effects for more setups. For bottom end you need good amp. and box - it's not the preamps fault.

i have to change the input, but it might been damaged by bad working by the pre-owner...

professional player

Plug your guitar in and just adjust the EQ a little and there it is, the familiar Marshall sound. Be patient, you can easily be lost in the EQ-jungle...

I use yamaha and fender guitars.
A Marshall valvestate power amp.
In the stereo effects loop i have a dbx Compressor a Digitech IPS 33 and an Alesis Quadraverb. It sounds just great and I can get most sound. Finally I run the system through a Rocktron Hush which is very good. There is a humming from the lead channel but it is easily whiped out with the hush.

It has never failed me. I have never had any problems with it whatsoever.

I play everything from jazz to heavy metal and this pre-amp does it for me. This is a great pre-amp. I've had it for 15 years and I will keep it for many more. If I lost it I would try to find a new one. But remember it is always up to each listener if they like the sound or not. My brother has a Mesa/Boogie and that sounds like a Boogie. Very nice sound, but this one sounds like a Marshal, a different sound but oh so lovely....

No noisy. I put into it JJ tubes. Warm sound.
I don't use the eq. You can switch on or off the eq from the pedalboard, but with the eq the volume goes down.
If you have inthe lead channel the gain 1 up, your sound is clear, perfect as the channel two.
But if you have up the gain 2 in the lead channel, the sound is muddy.
I have the gain 1 in the maximum, and gain two about 5. Great and clear sound.
NO muddy.
And this preamp sounds as a Marshall. It is a Marshall.

Series 9000. Made about 1990.
I play pop and rock. This preamp has a very good clean sound, a very good Marshall rythm and a very good and ultra gain solo channel.
FX loop, with stereo return.

Never problem

??

I have it for two years.
Great sound and never problems.

I am writing this review becasue I am tired of seeing ridiculous statements about the 'appalling' sound of this unit ... from people who have bought it second-hand and have not replaced the valves. The clean sound of this pre-amp is very transparent. Not surprising as in clean mode it is actually a good quality solid-state pre-amp. Crunch and Lead are exactly what you expect from a Marshall -- provided the valves are in good condiiton -- with a good range of sounds available via the 'voice' and 'drive' settings. Basically if you can't get the overdriven sound you want from this unit then you need devine intervention.

As previously described. Lots of knobs and buttons. I guess separate equalisation for lead channel would be good, but apart from that it has everything I need.

There are always compromises in cramming something into a 1U rack case. I suspect that the pcb mounted jack sockets on the 9001 are going to give up at some point but thus far it has been reliable. Inside it it all very tidy and well put together so should hold up well.

N/A

I've had lots of amps and bought this because I like the versatility of separate pre- and power- amp arrangements. The sound of the 9001 is (to my ears) very similar to the JMP1. I have never got into MIDI controllers so I prefer the 9001 on acocunt of its (relative) simplicity. For what it is, I think its a great product that can be bought very cheap second-hand.

if you follow the surgested settings in the manual you cant fail to get that lush marshall cleen sound but if you turn up the gain 1 on the lead channel to about 7 itl nock you to the floor! reading the outher reveiws pepole are comlaining about the buzz umm .. what buzz? its seams pritty dam quiet to me. there isnt many styles that you cant play it with but louds best!

i brought it about a year ago and its the one of the nicest sounding marshalls i ever played i use a marshall 8000 power amp and 2 marshall cabsand it sounds amazing tho the gain on the rythm channel sucks a bit! i play in a cover band we moastly play stp/pearl jam style stuff its the perfect gain and tube sound for this style, playd with a les paul custom obvoiosly mmmmmm.....

ive playd a few gigs with it and practisd with it to many times to count its been thrown around in the car and nothing has gone wrong a true marshall!

ummm never needed it but i printed the manual of the marshall site

i dnt eva wana have to replace it (only for a mesa/bogie but i cant se that happening anytime soon!)the only thing i can realy complain about is it shouldnt be a rack! i dont have a foot switch witch is a bugger so if anyone knows were i can get one or have one please email me thanx

The sound of the preamp is great. The biggest set back has been between the rhythm and clean channel. Having to compromise the overall level affects both channels. I would have enjoyed more versatility with having each channel independant of each other. At least the voice control is separate but there are major hassles trying to adjust the clean level since the unit has to be out of rack just to make adjustments. I mostly use the clean and rhythm channels. The Lead is a little over the top and good for other styles of music that I don't play anymore.

I've had this preamp since 1991 and have enjoyed its use ever since. The effects loop is great! I use a Roland SE50 and have had no trouble with the two since. I've gone thru various stages of tones and 9001 has been a trooper. The biggest drawbacks are the combinations used with this preamp. I first started using this preamp with a Carver mosfet power amp. Bad choice - I had to use the cabinet simulator to get me the beef I needed. I tried it with the Marshall power amp 9004 - no deal, very weak sounding. I then found a Peavey 50/50 tube power amp - Oh boy what a difference! I didn't need the cabinet simulator anymore and turned it off. The 50/50 has a the resonance and presence control that made the 9001 sing. I get my classic Marshall sound and other great combinations only a tweak away.

I haven't had much problems with this preamp other than my on/off switch. I opened the unit up and resoldered the broken solder joint on the board and the unit has been great ever since.

Never needed them and I hopefully never will (Maybe just for schematics).

I have been playing for 28 years and used Mesa/Boogie and Fender amps. I played in various bands ranging from Rock, Blues, Country and at one time hard rock and old metal. I would love to find a second one for a backup or use them simultaneously for other various options. The simple ease of use by just tweaking one knob on most settings have made this unit easy for me to use and gave me the preamp sound I was seeking.

I was able to get 3 great tones within 15 to 30 minutes of hooking it up. I will play with it more and see what I can come up with. I am impressed.

I am play a Hamer Studio with Duncan and PRS humbuckers. Great rock, blues, and my form of jazz tones. It cleans up pretty nice on the clean channel. I play somewhere between The Doobie Brothers and Santana. Haven't tried it with effects yet, but I have a bootie of them to mess with. I am playing it thorugh a late 60s Oliver B200 tube bass head. I run it into a Mesa/Boogie 1x12 cab. Sweet!!

Only had it a day, so I don't know. I always gig with backup because I usually buy used stuff, its cheaper you know.

I have dealt with Marshall before. I a Mosfet Lead 100 with 4x10 cab and they provided a manual and support at no charge. I suspect they will be as helpful as before.

I play Christian rock and praise & worship and it is a great addition to my arsenal of amps and effects. I can't wait to try it with my old Vox. I've been playing for 30 years. If I had to replace it, I would look for another. I do wish the eq wasn't shared eq, but I can live with that. I'm not that picky. It is very musical, it may inspire improvement in my playing and ability.

its a little rough to get a crisp low crunch out of the 9001 pre amp

the 9001 pre amp is ok, but just like the rest of the people that use it it just doesnt have a good bottom end crisp crunch. you can turn the hi mid and the low mid and the plain mids all the way off and give some base and some treble and it sounds better. i use a dod (metal x) pedal with it use the pedal on the clean chanel and you will have unbeleivable crunch oh nice and crisp and low that will bust you ribs not muddy at all, but that metal x peadal is what does it, i wish i had another pedal. but anyway it does the job with the preamp.

take care of the tubes and it will last ya a long time

i havnt had to deal with them yet but i here there awful.

i play stuff like bush,nickle back,stp and so on. ive been playing 22 years. if i lost this preamp i woulnt get another.

I have used this amp in cover bands for about 12 years,its been pretty user friendy,it has knobs,how easy can it be ,turn the knobs till the sound is right to your ear,if you cant do that, develop and ear.!it has two channels to change from a rythm or lead channel,use your volume knob on your guitar for the rest,its just that simple.
I use this preamp to cover a wide range of different bands,I use three differnt guitars,and a digitech effects unit,split stereo to a tube poweramp,and this makes for overall ease of use,no midi stuff to learn,just one pedal to switch into lead,and you can set the lead channel to be mild or ugly,I wouldnt be comfortable with anything to complicated,but the 9001 preamps are oldschool units and they do have there own sound and limitations,its the right preamp for my situation ,but it might not be for yours.

If your reading all these opinions,good for you ,you need to find your tone!!I use this in an all rack format,goes like this,9001 preamp to a peavey 60/60 all tube poweramp,then a digitech 256XL loops though the fxloop,I dont have a noise problem,and I only use one preset on the effects,I get my color change from switching between 3 different guitars,I have sided up this amp to many a guitar slingers with everything from Line6 modleing amps to real marshalls,I gotta tell ya it stands its ground quite well,in fact 8 out of 10 gigs I play,buy the end of the 1st set I have guitar players in the crowd commimg up and asking what Im playing through.I use a midrange chours setting in true stereo,with about 100 milsec,of delay left to right and alittle cut to the mid section on eq,into a marshall 1960 slant cab that has the mono or stereo swicth in the back ,Our cover band covers classic to newer alterative stuff so with a single coil guitar in line I can play the goo dolls or with a humbucker guitar in line I can play Judist Priest,so it covers all the stuff I need it to
If your trying to play the real heavey stuff it just wont get you there,you will need another preamp with double the gain,but if your looking for a mashall tone its all there,my only complaint with the 9001 is that I could use a little more gain from the rythm channel,the lead channel you can make so distored that it can be
almost mushy,if you get it to that point it will require eq adjustment.

Use this preamp for the last 12 years,somtimes 3and 4 nights a week,I retube it once a year,and beat it up the rest of the year,no break downs and have had no need for a backup once,and we play 3 to 4 hours per gig.per night

I have never had to venture into a repair or the need for tech help
I dont think there are any upgrades that are avalible,but if hepl is needed do to the age of these units you might be in best shape to start at the internet.

I mainly play rock,I have been playing for 25 years the 9001 is my main tone and if it were ripped off I would probly seek out another one.I love the fact that its all tube and that it has real tube tone,what I hate is that its rack.Seems like Marshall could have put out a head that sounds like this thing,I love that fact that its got knobs,I hate having to be a computer greek to figure out how a guitar amp works,this things easy,I worked at a music store when I bought it and I was able to compare it to several preamps over time ,ada,Kasha rock mod,halfer,tube works,art stuff,digitech stuff,Rocktron,and It just stood out to my ear,it had a more likable tone to me,so I got it.
As I said in the other comments I do wish it had a touch more gian in the rythm channel but thas it,It wont clean up 100% if your needing a Fender clean,dont ask for it,but it does clean up enough and it does encourage my playing.

easy layout, what you would normally expect for a marshall unit, not so easy trying to dial in a good sound

i run this thru my 8008 poweramp, used it with a variety of guitars, this is the worst amp i have ever played. i suppose it depends really what you play though, i play in an emo band and it just doesn't work for me, the lead channel is just mud, you can clean it up with the e.q. but due to it being shared it makes the clean channel sound aweful, the distortion is nice and heavy and have a nice valve sound and you can get some nice feedback, but trying to hear single notes within is impossible, playing on my mates zoom 505 you can get a better sound, the clean sound is alright can be quite warm but the lead channel just lets it down, and the shared eq is pointless as as soon as you make one channel sound good the other sounds bad, i regret getting rid of my 8100 valvestate head, that had a much tighter more defined lead sound, and you could actually get more than one useable sound out of it, i'm sorry but this unit is awefull, i am getting shot of it and getting a jmp-1

blew it up trying to make a footswitch, that was easily fixed, dropped it and the crunch channel stoped working which i don't use any way. but before that it had a problem with the power trasformer being lose, but easily fixed

no wonder they got rid of these and bought out the jmp-1, just don't buy one, its a disgrace to the marshall sound, if it were stolen i would probabally be happy

i have got a fender strat usa, and to have a good sound you have to take your time to find the good sound, it's hard to give a sound notation because it's a rack preamp and people use it with so many differente rack... the sound of this type of installation is differente from each personn.
But i like it......... i ofen use a wahwah (dunlop 95) may be when i m using wahwah the sound is to high but i have to work my sound.

I don't know many thing about this preamp, it seem that marshall had complletly forget it..... but as i m concern to this product i like it the clean sound is goog and had the marshall color.
3 channel considere like one clean one overdrive and un hard distortion; I play funk rock.

i use a marshall 8080 wtih it but i wil buy a tube el5050 to have a complete tube sound.
So i have got effect with midi verb4, and it will be better if 9001 coold work with midi command like JMP1.....
I don't have foot swihtch with my 9001 but i made one with a 3 channel uarshall footswitch, i use only 3 channel because loop activation don't interest me (i have a bypass on my midiverb).
so reliability is prety good

sa i ever say, i ask if marshall know that thay have contruct this product!! i m french and there are no many 9001 in france.....

may be i will buy a JMP1 but Marshall had stop the fabrication.... but i m sure to keep it in my rack!

With no FX loop=no hum.. .so no more hum there well at least 70% of it is gone, but there is a little hum left so I cleaned it out there went about 25% of it then if you mix high gain and high volume you get noise.. but you can advoid that!!!

I dunno about the channels some say it has 3 I see two and you can mix the two together? I only use the first one for the brightness it givese me the Rhythem channel is too blan for me. It has a FX loop that makes noise alot and it ticks me off over and over so I don't use it and the preamp is last in my chain. But I can get over it and sacrifice the FX loop, I have like 3 other pieces that have an FX loop. I did find the difference in the channels now... good and crap.

GREAT pawn shop piece read my othere review..

never dealt with it

I still use it now and it is like the worst looking piece in my rack people can tell what it is... all the writting is gone and I still gig with it.

VERY difficult to use - not so much that it is strange, but the settings are DECEIVING! Read below!

This thing gives AMAZING crunch and 'NuMetal' tone as they call it. It will give you Mesa-like grind, with extra-sexy Marshall complexity to it - man does it BURN! WoW! :))

What you gotta do is not very obvious - but believe me the tone is in there.

Start by turning all your speaker emulators off and turning the bass way down and trebble way up, and detune your guitar, try different tubes, etc. It's in there, believe me. The reviews on this site are from people who have not gone that deep into it.

Think outside the box! Just because it has a speaker emulator doesn't mean you gotta' use it. Just becasue the bass goes up to total flab doesn't mean you gotta use it, etc...

Well - it sure is amazing how some people bitch about these preamps and don't know what the hell they are talking about. For one it is dead quiet :P Check your location for rheostats and flourescents before you bitch. Disconnect your guitar from the unit - that's how to test how quiet it is for god's sake :P

Fine

People bitch about Marshall support. I managed to get manual coppies from them for this unit - didn't even charge me - not so bad :)

Man I wish Ebay was around when I bought these - it's so much cheaper now! I paid $300 each and have 2 of them! :P But I must say they do have amazing sound quality so it was worth it :) You clowns who can't get a good sound of it to save your life - start by thinking outside the box - this is a bass-heavy preamp. You need to 'de-bass' it for best sound - unless you are after the grunge tone LOL

This think Hum like crazy!!! I had to buy a Hush II super c to shut it up! It is in the main volume also... I can crank the gains up no change and the master volume up no change just after the 9 o'clock postion it goes crazy.. but I bought it so my solid state 8008 would sound more Marshally... you know that clasic gain.

Well the 5 band EQ is nice for the rounding of my sound I have three EQs, a parametric 3 band, the Pre's 5 band, and a 15 dual graphic eq for room modification and cab/amp changes(fine tweaking). Its got good channels but I only use the clean channels because I get my od and distortion from my RP7 that is the best piece ever made! I only give it an eight because some reason I can't tell a difference in the channels.

thing must be dependable. After I bought it, that rackmounts were bent in the bottom so I hammered it out and still works... for 35 buck i don't care... great tho. NEver broke on me and I don't crank it much tho.

never dealt with it, herd bad things about it tho.

great piece expectially for the price I paid... ripped the pawn shop off like crazy!

I don't understand why so many people feel that Marshall support is crap. I took my pre amp to Milton Keynes, left it with the service dept & picked it up the same day. I can only speak as I find & I can't fault Marshall servive.

I no longer own the pre amp. It was great - loads of valves, but it had a shared EQ & I needed something more versatile, so I finally took Geoff Whitehorn's advice & example & traded it for a JMP1. I was amazed at how little the pre amp was worth then even though it was stuffed with so many wonderful valves.

its not complex if you have some time to prepare a mix, between the 3 channels and the 5 band Eq, you have to start from the balance between all the 3 channels, clean, crunch, and lead, the Eq applies on the 3 bands, you can make a full complain on this gear if you are not into this for at least 10 years, if you have the appropriate guitar, effects and amp, you can make something really good with this preamp.
NOTE: if you put the speaker filter on, you have deeper bass tones, like megadeath or metallica, if you turned that off you have more crunch distortion and bright clean sounds
there is a shame that the clean and crunch doesn't have different gain controls.

I'm using this preamp with:
-Gibson les Paul custom equipped with a strange paff humbucker customized mic on the bridge (the one on the neck, is the original)
-zoom 1010 on the loop (a piece of crap, but good for a little touch on the clean sound)
-Marshall JCM 900 4100 (100 watt model) with Britt valves (5881)
-Dunlop cry baby wha GCB 95 (killer)
sometimes I use a whammy pedal, but doesn't make sense to put it here.
ok ok ok, I spend some time working between the amp, preamp, and effects to get what I was looking for, but lets make the review:

noise: if you have a good power outlet you might not have any undesired buzz, or tension line noise (eeeeee) , one thing that i have to say about this preamp, is that I never get radio interference on this gear, (I got that on many marshalls, fenders, dean markley)
On the clean channel you haven got anything but your guitar sound, and even in high volume and distortion, I never have a undesired feedback noise.
so I can rank this on 10, you can get many sounds if you know the right combination (remember that this is only a preamp, not a multieffect rack unit, so if you look for a Gilmore sound get also a multi effect rack unit)

I have used it for a year on heavy duty situations, sometimes every day, you need to take a pair of fuses and valves, if I ever have a problem with it I can jump back the preamp and use the Marshall, I can keep going with the Marshall distortion. But in any case I'm planing to get another for backup

if you ever see any replacement for a Marshall gear buy it!!!, don't think it twice!!, never relay on Marshall support at all, its like looking for the gold at the end of the rainbow!!!

i play hard rock, and as i am a fan from Slash and Zakk wylde, and i ofenly need a ton of distortion to achieve what i need, i play the guitar since i was 10 and now im about to be 23, so in my 10 years of guitar playng (the first 3 i was training to be one!) I used a lot of distortions, and amps, and i learn this, nothing is a piece of shit (exept the zoom 1010) its only a metter to find the perfect mach between guitar, amp an efects, you never are going to get blues sound on a jackson soloist!, so every thing is good for something!
PD: if you are looking for a good foot swich tor this try the FS4 Footcontroler from Laney