Marshall 50 Watt JMP ”Bluesbreaker” Tremolo 2×12 combo 1968

OK, here it is, the fabled JMP “Bluesbreaker” combo, this one from 1968. The real deal! The amp is in great condition, minor changes aside as detailed below, and of course sounds fantastic.

DETAILS

Model 1962 (bass circuit with tremolo), serial T/A 10338.

No date on inspection sticker, but the electrolytic condensers are stamped ”6828” = 28th week of 1968, which also matches the late 1967 speaker date stamps, making the amp a 1968 beyond any doubt.

All major components are original, not least all transformers:

• Mains transformer: Drake serial 1202-118
• Output transformer: Drake 784-139

The following items have been changed or differ from original:

• 2 electrolytic condensers in the bias circuit
• 2 switches – ”Power” and ”Standby”
• 1 transistor in the tremolo-circuit
• Speaker plugs and cable

Everything else is original, including handles, tremolo footswitch, basketweave front cloth, gold Marshall badge, plexiglass front and back panels, and the original Bulgin power cable socket.

TUBES

• 4 Brimar ECC83 (likely to be the originals)
• 1 Mullard xf3 EL34
• Philips xf3 EL34

SPEAKERS

2 12” Celestion G12M ”Greenback”, model T1221 – 25 Watts 75Hz (Lead) speakers with Pulsonic membranes. The speakers have the following date codes:

• 14LM = 14. november 1967
• 28LM = 28. november 1967

Both speakers feature gold Marshall stickers.