Marshall 9100 Power Amp

4 x 5881 valves, 4 (or 2 can't remember) x ecc81 valves.

This is stage 1 for me upgrading from a Mesa Calibre 50+ head to a rack setup with Triaxis. I saw this power amp on ebay for a great price and so bought it untested. I was slighly disappointed to find it had 5881 valves which are similar to the 6L6GC in my Mesa. I was hoping it had EL34's. Well nevermind coz its a totally different sounding power stage.
I am writing this review not yet having taken delivery of the Triaxis so I am using the effects send of the Calibre to deliver my preamp signal into the 9100.
I won't bore you with the usual adjustment period to exploring a new amp, instead here are my conclusions.
1) This amp has opened up a world of sounds that I never had before, being a pure Mesa man. Even though this is a 5881 amp I can get very Marshall sounds out of it that are impossible with the Mesa. The voicing switch is excellent, though I'd probably only use it on 'B' live as it cuts so much better. Again the precence control is excellent and could probably make the 'A' voicing more useable live.
Volume wise I was underwhelmed. It's not as loud as the Mesa. And here's the really big downside. Yes, as mentioned by the previous reviewer, the bottom end sucks. I mean it's crap. It's hardly there and what is there has no definition. With the Mesa power stage I can get an incredibly chunky but pure rhythm sound for metal aka Metallica, whatever. Not so with the 9100. It seems like 50W of juice is not enough to power the bass frequencies in this guy. Now this may not matter a lot live, but I am a tone junkie and do most of my playing in my room (sadly at my age :). I like to have a killer tone. I had John Petrucci before, now I have compromise. Apart from that I really like the tone. It's definately Marshall despite not being EL34 endowed. I can get a very close Megadeth sound with a bit of tweaking and the right guitar - their guitar sounds were never that chunky anyway. Also those 'edge of distortion' sounds are now more obtainable. The Mesa is more of an all-gain or no-gain amp.

Looks pretty damn reliable and I've looked under the hood. The knobs and voicing switch are vulnerable if knocked but they should be out harms way in most situations. Havent owned it long enough to give it more than 7.

Yeh right, Holler for a Marshall (oz joke)

Overall I am disappointed with the overall tonal QUALITY. The sounds themselves are cool though and have expanded my range a lot. I have a feeling the triaxis will do wonders for me again, but I don't know that it can compensate for the lack of bass and bass clarity.
Probably a great workhorse, but keep looking if you want that perfect power amp. I may buy a VHT 50/50 at some time in the future, but at 4-5 times the price I'm not in a hurry.

Everyone has talked about the features... and it's simple... gain... brightness... and that's that. Two monoblocks of 50w power. You can go from jazz to heavy-metal on this one... just choose your pre-amp accordingly.

I use a "Parker Fly", "Washburn N4" or a "Gibson Les Paul Custom" through a A-B/Y "Morley" split-box (circuit A includes an "ADA MPX-2", a "Morley Wah" and a "Morley Volume" while circuit B has nothing but "Marshall" floor pedals like "The Guv'nor" or the "Drive Master"). I've learned that the 9100 is an excelent amp... it's not the best amp in the world, but it's great. I've learned that the ADA is not good enough for this... I'll be looking for a "Tri-Axis" soon... and some effects too...

I trust this baby 100% !... The tubes smoke and show no sign of wearing off... but I know they won't last forever, although they're original EL-34...

N/A... never needed.

It's beautiful, it sounds great... it's not a Tri-Amp or a Soldano, but it does NOT cost you $2500. I will be looking for the EL-34 100/100 to have in the studio... as soon as I get my hand on $600 to spend.

Features? Well; two mono amps in one weighty package with volume, presence and voice control for each. Kinda' spartan. Cool. Less to break, and just how I think a power amp should be.

Put a Pod in front of this thing. I'm still dissapointed in how flat the JMP-1 sounds with the 9100, but the Pod? YOW! Glassy to Howling with some monsterous tone throughout over a pair of 1960s. To my ear, the best way to take advantage of this setup is with a medium output pickup (not too hot). While I still have the JMP-1 laying around, the Mesa has gone ... If I can find another 9100 for a reasonable price I'll grab it.

Had it five years. Never any problems.

The others that have posted have already explained the features very well. I will just elaborate on some of them. The amp is very versatile. Others have said little about the voicing switch. It lends more presence and quicker response(more of a modern tone.) I'm glad I decided on the 9100 and not the 9200. This amp is VERY LOUD. I have never needed to crank it past 50%. Lots of that glassy shimmer and bottom end punch we expect from Marshall.

I play an Ibanez RG 3120 Prestige into a Marshall JMP-1 and Korg A-1 processor that ends up going into a Marshall 1960 Vintage Slant 4/12. I run the cab in stereo and mike each side. I dream of how this would sound running two full stacks in stereo (which it can!). I use this setup for studio and live dates. It's great that you can switch impedance on the output for added flexibility. I play many styles of music and it covers them all well. When you crank the amp for stage it lends a lot of extra saturation and sustain to the tone and you will need to roll off a bit of gain on your distortion if you programmed it at living room volume (unless you enjoy pissing off your neighbors).

No problems at all.

N/A

I've been playing 20 years and have primarily been a Marshall user so I guess I'm predjudiced. But I do have a few peeves. One is it's size and weight(very heavy). Another is when you engage the rocker switches on the front panel, sometimes it pops very loudly (it's a good idea to power up with volume down). I tried 3 units and they all did this. I found out that it's normal. And one more, the volume and presence knobs have no numbers on them so it's very difficult to tell on a dark stage what they're set on. I had to put a spot of paint on the knob. If they used gold tone plastic Les Paul type knobs with numbers instead of the featureless gold plated metal knobs, It would lighten up the weight a tiny bit and be easier to read. Otherwise I am a happy camper and would probably buy another one.

The features listed above. Suit my needs, and this is an old Power Amp, remember.

The sound is simple. BRUTAL. I thought that 50+50 was little for me, and thrust me, the people knows that I play LOUD, REALLY LOUD, but this strange monster have an amount of power that will make tremble the hair of your legs when you play!!!!!!
Clear in clean sounds, warm, crystal and loud when distorted. High bottom end. Incredible.

I use it with a Triaxis as preamp, and it is perfect.

Yeah, it's like a tank, sure.

It's a warhorse, and the amount of power is so big that it seems to have 16 Valves.

It's an amazing power amp, but very difficult to find actually.

This power amp is a dual monoblock construction. Is like having two 50 watt mono power amps. Each power amp has it's own gain, presence and voicing controls, two 5881 power tubes, one 12ax7 preamp tube and one 12at7 tube for something about the phase... (try to get the manual if you want to know the use of that 12at7...).
All the controls (except the two power on(s) and standby(s), one for each 50w power amp...) are recessed to avoid acidental reconfiguration.
Is a nice (I mean, good looking) power amp: gold plated, you can see the tubes lighting your room when you play with the lights off...
The voicing switches can be controlled by a footswich (you can switch two at the same time or not, if you want...).
I think 100 w is more than enough, but if you want more, there's two links in the backside of this power amp so you can connect your preamp to two power amps. There is also two speaker outs (of course...) per channel and a impedance selector: 8 or 16 ohm; if you select 8, then you can connect one 8 ohm speaker or two 16 ohm speakers per channel.
There is also a cooling fan with variable speed: faster if you have the two power amps working.
Very cool features... I would give it a 10 if I did not already know the Mesa 2:90...

I have a Mesa Triaxis and two Mesa cabinets with 1*12 EVM. It is loud enougth to shake all around. Good definition, maybe lacking some bass, but I think the problem comes from the guitar I play (a cheap Ibanez).
I tried to work with the voicings and presences and came to a better sound: the voicings are swiched on to give that definition to the sound (more top end); the presences are totaly rolled down. I think that the presences do not work very well... but I like the sound I get setting the presences this way.

Neves broke...

Never dealt...

I play for about 10 years and many styles of music. I started with a valvestate combo, than a zoom 9150 and Marshall 9100, than kick the zoom away and bought the triaxis. If it was stolen, I am not very sure about buy it again, since the triaxis seems to work better with the 2:90... but for the money, I think I must forget the 2:90. The Marshall is an excelent power amp and a great deal.