The Marshall JMP Model 1987 Lead MKII is one of the definitive non-master volume British tube heads, delivering the raw, dynamic "plexi-style" experience in a slightly more controlled 50-watt format. This 1976 example represents the metal-panel JMP era, retaining the classic four-input design with Normal and High Treble channels that can be jumped for rich, harmonically complex overdrive. Known for its punchy midrange, tight low end, and explosive response when pushed, the 1987 circuit is a cornerstone of classic rock tone.

This particular unit has been professionally modified for enhanced versatility, now equipped to run a pair of 6550 power tubes for increased headroom and a firmer low-end response. It also features a tube-driven effects loop, adding modern usability while retaining the core vintage circuit character. The amp remains true to its non-master volume design, delivering authentic power section saturation and touch sensitivity.

This unit is in very good vintage condition with expected cosmetic wear for its age, including light marks and wear to the tolex and hardware. WYSIWYG. Fully functional and ready for stage or studio use.

Note: If you would like to run EL34s in this head, you will need to have a professional amp technician make the change for you - EL34 and 6550 are not interchangeable and have different bias adjustments needed.

Specifications

• Make: Marshall
• Model: JMP Model 1987 Lead MKII
• Serial #: 0910H
• Year: 1976
• Country of Manufacture: United Kingdom
• Power Output: 50 Watts
• Power Tubes: 2 × 6550 (Modified for 6550 operation)
• Preamp Tubes: 4 × 12AX7 (Additional tube added for FX loop circuit)
• Channels: 2 (Normal, High Treble)
• Voicing Modes: Channel jumping capable via 4-input design
• EQ Controls: Presence, Bass, Middle, Treble
• Special Features: Non-master volume circuit, 4-input layout
• Effects Loop: Tube-driven series loop (post-preamp, added via additional 12AX7 gain stage)
• Modifications: Power section reconfigured for 6550 tubes (bias and circuit adjustments), tube-buffered effects loop added utilizing additional 12AX7 stage
• Impedance Options: 4Ω, 8Ω, 16Ω

Please note that photos are representative of the condition; not every mark can be visually included, and portions not visible in photos should be assumed to be of consistent condition.