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Tom Berger

Marshall JMP-1 Tube MIDI Guitar Preamp

Sound Quality

I often see critisism about "sound". However, sound is often a matter of opinion. Remember this point in any reviews you read. What will appeal to one may not appeal to another. If you want to know how it's going to sound for you, I recommend you take your axe, rig and cabinet to the place of purchase, and try it. You absolutely NEED to use your OWN gear to hear if the sound YOU like is being generated with YOUR gear. This is a must - because if I say it has good crunch and sustain, how do you interpret this? Impossible - again one person's perception / opinion is different to another's. Personally, I found the JMP-1 to be *THE* sound I always craved for. The sound I like could best be described as the "brown" distorted tone that is evident on the early Van Halen records. However, a wide range of tone can be created by adjusting the gain, EQ levels, and selecting between distortion modes (OD1 and OD2). For example, it was easy to replicate the tone of my Marshall JCM800 (2203) head. Thats the beauty of the JMP-1. You can reproduce many of the classic Marshall tones, and store them in one of the presets (there are 100 presets available). I have a feeling that those who whine about the tone of the JMP-1, simply don't know, or haven't taken the time to set it up properly. Remember, this is a pre-amp, not an effects processor. It has a specific task. For me, the JMP-1 is the LAST WORD in pre-amp tonal magic whether it be in rack, head, or combo format. Suddenly my distortion stomp boxes have been sent to the stomp-box retirement home.


I have known of others who have used the JMP-1 without a hitch for years. My JMP-1 has a minor problem with the Data Entry control knob. It seems stiff in places, and tends to jump skip numbers now and then. I think the shaft is bent slightly. Probably from previous owner abuse. This is a minor problem though. More an annoyance than a fault.

General Comments

I've used various amps over some 16 years now, and I must honestly say that the JMP-1 exeeds all expectations. I run my JMP-1 with a Rocktron Intellifex DSP. This combination is just mind blowing. Beautiful, noiseless tone. However, if any Marshall engineers read this, here are some suggestions: 1) Ventilation of the case in my opinion is not adequate, especially since it runs 2 valves inside. There are small ventilation slots on the top and bottom of the case. These are in a bad position because rising heat will only heat up the rack component above it, so I recommended that the JMP-1 is placed at the top position of your rack. The vetilation holes under the unit seem silly because the circuit board in the unit will inhibit proper flow through ventilation. It would have been nice to see one of those small computer fans installed somewhere in the unit. I would have been happy to pay an extra $20 (parts and labour) for this inclusion as standard. 2) It would have been nice for the patch display to read an name for the patch, as well as a number. With 100 presets, it's too hard to remember what patch 58 is. I'm sure guitarists don't want to have to carry a sound setting chart with descriptions around with them. I know that's extra cost to the manufacturer, but it would be a nice touch. Overall, I can't fault the JMP-1. I am often critical about most things, but in this case, my average vote of 9 for this product is very well deserved. In conjunction with the Rocktron Intellifex DSP, my search for the ultimate tone is over. Thank you Mr. Marshall.

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