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Marshall JMP-1 Tube MIDI Guitar Preamp

Sound Quality

I can get the sounds of my favorite guitar players and many others, because they are using 12AX7 preamps in racks or in Marshall combos or heads and cabs. Can I get a sound like Kurt Cobain? Sort of. its not what he used. Can I get a Hendrix sound going through the pre and my Marshall 50/50 all tube EL34 power amp. Absolutely. Can I get the same sound as the Beatles in the early 60's. Hell no! I need a Vox for that. But the Marshall and the Vox both have great tube tone, they're just different. With this preamp I can get the sounds of some great STUDIO albums from artists like Journey, Rush, Van Halen, Gary Moore, Deep Purple, etc. I need a Mesa or a Dumble to get my favorite Larry Carlton Sounds. I use many different rack and foot pedal effects units and they all induce some kind of noise into the signal. That is unavoidable. That's why noise gates, compressors, and limiters where created. It nature folks. The physics of analog electricity and sound just works that way when you are talking about gain. I use this preamp through a Marshall 50/50 EL34 Dual Monobloc Amplifier. It sounds incredible. Tones of lows and highs whenever and wherever I want it. I also use them through my Vox AC30s and it really gives off a different and cool sound as well. Between the two setups I can dial in a lot of different sounds and I can even mix then=m together to varying degrees to get some of those different timbres, much in the way Eric Johnson does with his Marshall/Fender setups along with a mixer and his array of different footpedal effects.


I have used the same two JMP-1 preamps for over 10 years now and they have never had a problem. They get hot even when being cooled properly. No problems whatsoever. I have replaced tubes in them and each time, these units perform up to standard every time, that standard being 100%. I would never use any gear on a gig without a backup because of the myriad of other problems or accidents that can happen or be caused by others. A preamp is at the heart of your guitar's sound system so a backup is wise for any preamp. Some effects you can live without when they die on a gig.

General Comments

I play all sorts of styles of music and I never consider myself a slave to one brand of amp, guitar, or effect unit. When I need that signature crunch at any level of volume and distortion I can always count on Marshall. They invented the sound (with a tiny bit of help from the modified Fender Bassman circuit).


I have been a musician all my life, and grew up in a musical family. We all play and studied music formally. I have been playing guitar for nearly 30 years. I own several British-made Vox AC30s, Marshal cabs, Line 6 effects, Eventide, Ensoniq, tc Electronic. I use some MXR, Ibanez, BOSS, Roland effetcs and Ernie Ball pedals along with a Bradshaw switching system and a Sound Sculpture Switchblade.


I would replace this unit in a heartbeat. So many of the sounds people hear from guitars are generated by the Marshall preamp. And it just sounds great anyway. There is nothing about the unit I do not like. I like the ability to bring MIDI into the equation. I have owned Marshall heads and its nice to be able to recal a wide range of different sounds from the push of a button, and also because it is a tube unit. You cannot beat tubes for guitar. Tubes add a character and warmth you can't easily find in a tone of solid-state units.


It helps me make music in the way most of the gear i have does, itcan generate a wide enough array of "colors" that I can come up with something I feel fits into a particular piece of music.



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