1967 Marshall JTM 50 "Black Flag" Plexi | Original Drake 784-128 & Vintage Tesla Blue Glass EL34s

The Holy Grail of Transitional Plexis: The 1967 Marshall JTM 50

This is a rare opportunity to own a "time-capsule" piece of rock history. This 1967 Marshall JTM 50 features the iconic and highly coveted "Black Flag" J.T.M. faceplate—a hallmark of the brief transitional period between the JTM 45 and the JMP 50.

Investment-Grade Originality

Unlike many vintage Marshalls that have been modified or "parted out" over the decades, this chassis remains in exceptionally honest, original condition.

• Transformers: Features the legendary Drake 784-128 Output Transformer, the definitive source of the mid-60s Marshall "growl."
• Circuitry: The board is populated with original Mullard "Mustard" capacitors and a period-correct TCC Electropack filter cap.
• The Tubes: Equipped with a matched pair of rare, vintage Tesla "Blue Glass" EL34s (Roznov factory). These tubes are world-renowned for their aggressive harmonic content and durability.

Condition Report

• Faceplate: Original gold Plexiglas "Black Flag" panel with authentic age-related patina.
• Chassis: Clean, with original hardware and "untouched" solder joints on the main board.
• Tone: This is the "Plexi" sound—thick, touch-sensitive, and harmonically rich.

Previous Owner

• Edgar Winter's Lead Guitarist: This amp was purchased for gigs with the Edgar Winter band in the early to mid 90s.

Technical Specifications

• Year: 1967
• Model: JTM 50 (Transitional)
• Faceplate: Original Plexiglas "Black Flag"
• Output Transformer: Drake 784-128 (Original)CapacitorsMullard Mustard (Original)
• Power Tubes: Vintage Tesla EL34 (Blue/Purple Glass)

General Information

• Serial Number: 10550
• Model: JTM50
• Condition: Very Good
• Manufactured Date: 1967
• Manufactured Location: England

Condition Notes

• The "Mid" knob is very stiff and hard to turn
• Presence & Mid knob likely have been replaced
• The power indicator light seems to be new
• There is a small crack in the faceplate near the power indicator light
• An internal bias control added
• Standby switch is a bit finicky and likely needs cleaned
• Screen resistors have been replaced
• An IEC has been added BUT no modifications have been made. The original Bulgin socket is included
• Road case is included