For sale is a Marshall JMP-1 Valve MIDI Preamp, one of the most iconic rack guitar preamps ever produced by Marshall. Manufactured in England in the 1990s, the JMP-1 became a cornerstone of professional rack systems and was widely used in studio and touring rigs.

The JMP-1 combines tube warmth with digital control, offering classic Marshall tones in a compact rack format. The preamp features two ECC83/12AX7 tubes, providing authentic valve character, while MIDI capability allows full integration with rack systems, switching units and modern pedalboards.

The unit offers four main amp modes:

• Clean 1 – classic Marshall clean tone
• Clean 2 – warmer clean with more body
• OD1 – classic Marshall crunch
• OD2 – higher gain lead tone

Additional tone shaping includes Volume, Gain, Bass, Middle, Treble, Presence, as well as programmable effects loop level and speaker emulator outputs for direct recording or live use.

Thanks to MIDI programmability, the JMP-1 allows users to store presets and integrate seamlessly with rack processors and switching systems. It pairs perfectly with power amps such as the Marshall 9100 or 9200, creating a classic Marshall rack rig.

Condition

Cosmetic condition is as shown in the photos.
There are visible scratches on the top cover typical for rack-mounted equipment.

The unit works properly.

Specifications

Model: Marshall JMP-1
Type: Valve MIDI Guitar Preamp

Production: Made in England

Tubes: 2 × ECC83 / 12AX7

Amp modes:
• Clean 1
• Clean 2
• OD1
• OD2

Controls:
Volume, Gain, Bass, Middle, Treble, Presence, Effects level

Connections:
MIDI In / Thru / Out
Effects Loop
Footswitch
Speaker Emulator Outputs
Master Outputs

Rack size: 1U