Marshall amplifiers have powered rock for generations, shaping modern music with their iconic roar and defining the sound of legendary guitarists worldwide.
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When rock legends needed that earth-shaking roar, they cranked their Marshall Plexi amps to eleven. Now, Synergy and Marshall have bottled that lightning in a preamp module that delivers the growl, bite, and soul of a cranked JMP at any volume. This isn't just another preamp — it's your direct line to the sound that built rock 'n' roll.
The Plexi Powerhouse
The JMP module packs serious punch with its dual-channel design and innovative "0-watt power amp" circuit. Think of it as fitting an entire Marshall stack into a compact module that sits perfectly in your rack or modular setup.
Dual Independent Channels: Two identical channels give you everything from sparkling cleans to thick, harmonically rich distortion. Each channel features Volume 1 (bright input), Volume 2 (normal input), and independent Bass, Middle, and Treble controls.
60s/70s Era Switches: Toggle between the rounder, smoother tone of early '60s JMPs or the tighter, more aggressive bite of '70s models. It's like having two legendary amps in one module.
0-Watt Poweramp Circuit: This isn't just a preamp — it includes a phase inverter and transformer that captures the dynamic response and harmonic complexity of a cranked Marshall without the ear-splitting volume.
Touch Sensitivity That Responds to Your Soul
The JMP module doesn't just sound like a Marshall — it feels like one. The touch-sensitive response means your playing dynamics come through crystal clear, whether you're digging in for aggressive rhythms or backing off for clean passages.
True Tube Warmth: Two 12AX7 preamp tubes deliver the rich harmonic performance that makes tube amps irreplaceable. Your notes bloom with natural compression and organic saturation.
Volume Jumping Control: Volume 1 and Volume 2 controls work just like jumping inputs on the original Plexi, giving you precise control over your gain structure and letting you blend bright and normal channels.
Bright Switches: Four independent bright switches let you dial in the perfect high-end response for each volume control — customization that would normally require a tech visit.
Marshall DNA Meets Modern Convenience
This module captures every nuance of the original JMP circuit while adding modern flexibility that touring musicians demand.
Cathode Select Function: A three-position switch lets you adjust the input tube bass response, affecting the feel and tightness. Experiment with different component combinations to find your perfect match.
Independent Master Volumes: Balance your rhythm and lead settings perfectly with separate master controls for each channel. No more volume jumps between clean and dirty tones.
Easy Installation: Slides effortlessly into any Synergy preamp dock. Swap modules in seconds to go from Marshall crunch to Fender sparkle to high-gain mayhem.
The Sound That Shaped Generations
The JMP module isn't just about specs and circuits — it's about plugging into the same sonic DNA that powered Hendrix's feedback symphonies, Page's thunderous riffs, and Van Halen's groundbreaking solos. Whether you're laying down tracks in the studio or commanding the stage, this module delivers the legendary Marshall tone that's been the backbone of rock for over half a century.
JMP 2-Channel Preamp Features:
All-tube preamp module based on the legendary Marshall JMP "Plexi" amplifier
2 x 12AX7 preamp tubes for rich harmonic performance
Built-in 0-watt power amp and phase inverter circuit
Two identical channels with Volume 1, Volume 2, Bass, Middle, Treble controls
Volume 1 & Volume 2 replicate original Plexi "Bright" and "Normal" inputs
60s/70s era switch per channel for vintage tone variations
Independent master level per channel for precise balance
Four bright switches for customizable high-end response
Three-position cathode select function for bass response tuning
Easy installation and removal from Synergy preamp docks
This is way cooler to actually have than watching Y-tube vid's of it.
I can't believe how much this truely sounds like the JMP's from the 60's & 70's. The only way to appreciate the tonality of this module is to get one! 🎸
Published date
11/17/25
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2
0
Jeff m. 🇺🇸
Super lead in a box
Great tone on this one. I exchange the plexi module for this one and its way better. Authentic marshall tones in this one.
Published date
10/28/25
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1
0
Matthew Z. 🇺🇸
Verified Buyer
Amazing!
Amazing!
Published date
02/21/26
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0
0
Bradley L. 🇺🇸
Verified Buyer
JMP Module
This is just like having a Marshall in the house !! Loving Synergy !!!
Published date
01/24/26
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0
0
James D. 🇺🇸
Verified Buyer
Great vintage Marshall tones with
Great vintage Marshall tones with this module. Much more practical and easier to incorporate into your rig than an old, expensive, and insanely loud amp head.
Takes a moment and some experimenting with the two volume controls and bright switches to get used to the interface but after that you'll be...
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