Marshall JMP 1992 Super Bass 100W 1976 - Black Tolex

1976 Marshall JMP 1992 Super Bass 100W – Original Vintage Tube Head

For sale is an original 1976 Marshall JMP 1992 Super Bass 100W vintage tube amplifier head.

This is a genuine example from the classic Marshall JMP era. The amplifier has been preserved in a highly original condition and has not been cosmetically restored or modernized.

The amplifier is fully functional and has been tested with a guitar.

One of the most important features of this particular amplifier is the originality of its circuit, transformers and internal components.

Originality & Circuit Details

The original Marshall ST1 iss. 202 PCB is in excellent condition and appears to retain its complete original factory circuit.

There are no visible signs of burned or lifted traces, added jumper wires or obvious circuit modifications.

The amplifier retains:

• Original Drake output transformer: C2668
• Original Drake power transformer: T3836 / 1202-324
• Original quad of vintage Valvo EL34 power tubes
• Original blue DALY 50+50 µF filter capacitors, date coded 75/28 UK
• Original yellow film / coupling capacitors, including the original 0.022 µF coupling capacitors
• Original Piher resistors
• Original Cliff UK input jacks
• Original front-panel potentiometer bodies
• Original factory-style internal wiring
• Original ground bus connections
• Original bias trimmer

The circuit and internal construction appear unmolested, with no obvious aftermarket components or modification wiring visible.

The amplifier has deliberately not been modernized or cosmetically restored. The aim has been to preserve its original vintage character and components.

Original Potentiometers & Wiring

Both front-panel Volume potentiometers are original to the amplifier.

The original potentiometer bodies, markings, solder tabs and internal wiring are still present.

The wiring to the chassis, including the original pink and black wires and ground bus connection, appears consistent with the original factory construction.

Volume I

The potentiometer itself is original. The shaft is broken at the end.

I have deliberately not replaced the potentiometer in order to preserve the amplifier's originality. The shaft can be repaired or the potentiometer can be replaced if desired.

Volume II

The potentiometer itself is also original.

The external mounting nut has been replaced with a metal nut and washer at some point in the amplifier's history.

The potentiometers themselves have therefore not been replaced with modern aftermarket parts.

Tubes & Technical Condition

The amplifier was carefully powered up using a Variac and subsequently tested with a guitar.

All four original Valvo EL34 power tubes are present and functioning.

The amplifier runs properly at normal mains voltage.

Channel II was successfully tested with a guitar.

To my knowledge, the amplifier has not previously been repaired or modified.

As this is a nearly 50-year-old vintage tube amplifier, a professional inspection by a qualified amplifier technician is recommended before intensive studio, stage or touring use.

Known Minor Issues

Please study all photos carefully.

Volume I potentiometer

The original Volume I potentiometer has a broken shaft.

The potentiometer itself is original and has deliberately not been replaced.

Missing control knobs

Two control knobs are currently missing.

This is clearly visible in the photos.

Impedance Selector Plug

The original impedance selector plug is currently missing.

A replacement plug has already been ordered. Once it arrives, it will be added to the amplifier and the listing will be updated accordingly.

Cosmetic wear

The cabinet and Tolex show normal signs of age and use.

For a 1976 vintage amplifier, the overall condition should be judged from the detailed photos.

Identification

• Model: Marshall JMP 1992 Super Bass 100W
• Year: 1976
• Serial number: SB/A 00810
• Country of manufacture: England

Testing & Collection

Due to the age, weight and sensitivity of this vintage amplifier, I do NOT offer shipping.

The buyer is welcome and encouraged to bring their own guitar and test the amplifier personally before purchasing.

The amplifier can be inspected and tested in Gladbeck, Germany, by appointment.

If you cannot collect it yourself, you may arrange for a trusted person or a suitable transport company to collect it on your behalf.

NO SHIPPING.

This item is described to the best of my knowledge and ability, and all known issues have been disclosed above. Please review all photos carefully and feel free to ask questions or arrange an in-person inspection before purchasing.

Private sale. No returns or warranty.