1966–1967 Marshall JTM100 “Black Flag” Super P.A. 100W Plexi – Exceptionally Preserved – Original Valves – Collector-Owned for 40 Years – Tested & Working

Offered for sale is a rare Marshall JTM100 “Black Flag” Super P.A. 100-watt head, dating to approximately 1966–1967, serial number SP/20761.

This is a particularly appealing example for the collector who values originality, preservation and history. The amplifier spent approximately 40 years in a collector’s living room, preserved in the same configuration in which it is offered today.

Its exceptional state of preservation is especially apparent in the chassis, internal construction and wiring, as well as the beautifully surviving original gold Plexiglas panels.

The amplifier has been tested and works flawlessly in its current configuration.

Exceptional chassis and internal condition

The chassis and internal wiring are particular highlights of this amplifier. Their overall appearance is unusually fresh and remarkably well preserved, approaching a near-new presentation in many areas — particularly impressive for an amplifier of this age.

The original hand-wired construction retains the layout, workmanship and period components that make these early Marshalls so fascinating and desirable. It offers a wonderful opportunity to appreciate an early Marshall in its preserved, original state.

There are, naturally, some genuine age-related marks, localised oxidation and traces of dust, all visible in the photographs. These details have not been cosmetically restored away. The attraction here is its exceptional preservation and authenticity, including the honest patina accumulated over almost six decades.

Beautiful original Plexi panels

Both the front and rear gold Plexiglas panels are in very good condition.

They are free from cracks and additional drilled holes, retaining their original lettering, layout and distinctive golden appearance. Normal age-related surface marks and patina are present, as illustrated in the photographs, but the overall presentation is particularly attractive.

The original J.T.M. “Black Flag” marking remains on the front panel. The rear panel carries the Super P.A. 100W designation and serial number SP/20761.

Well-preserved original Plexi panels are an important part of the appeal of an early Marshall, and these are a particularly pleasing feature of this example.

Exterior condition

The black Tolex covering presents beautifully overall, retaining its distinctive original texture and period appearance. The gold piping, carrying handle and hardware complete the authentic presentation.

Please note that the front Marshall script logo is missing, with its original mounting marks visible. No replacement logo has been fitted for the sale.

Please examine the photographs for the precise cosmetic condition, including the small marks and imperfections consistent with its age.

Originality and collector history

To the best of my knowledge, the amplifier is 100% original in its surviving components, including the valves currently fitted.

It spent approximately four decades in a collector’s living room, in the same configuration in which it is offered today. It has not been restored, modernised or cosmetically refurbished for this sale.

The remaining valves are understood to be original to the amplifier, rather than a recently installed set selected to create a period-correct appearance.

For clarity, two of the four EL34 output valves are missing and are not included. The front Marshall script logo is also absent. These points are disclosed openly and are visible in the photographs.

Its long period of domestic collector ownership is an important part of its history and helps explain its unusually well-preserved presentation.

The Black Flag era

The “Black Flag” Marshalls represent a brief and highly interesting chapter in the company’s early history.

The nickname comes from the small black rectangular J.T.M. marking on the gold Plexi front panel. These amplifiers belong to the transitional period between the earlier JTM designs and the subsequent JMP models, with the Black Flag designation particularly associated with 1967.

This was a formative period for Marshall, as its early 100-watt amplifiers developed into the equipment that would help define British rock amplification.

Their short production period, distinctive appearance and position within Marshall’s early development make the Black Flag models especially appealing to collectors.

Early Marshall production involved running changes and overlapping features. This example is therefore described as circa 1966–1967 rather than being assigned an unsupported exact production date.

The Super P.A. configuration

The Super P.A. is a distinctive member of the early 100-watt Marshall family, featuring four input channels and eight input sockets, with individual channel volume controls and shared Presence, Bass, Middle and Treble controls.

Although originally intended for public-address applications, these early valve PA heads also attract guitarists interested in vintage Marshall amplification.

For collectors, the unusual eight-input layout and the model’s place within the early Marshall range add to its appeal. This example retains its original Super P.A. identity and presentation.

Tested and fully operational

The amplifier has been tested and works flawlessly in its current configuration, with two EL34 output valves fitted. The other two output valves are missing and are not included in the sale.

It is offered as a working vintage amplifier, with its original character and exceptionally well-preserved construction intact.

If you intend to return it to regular, sustained use at high volume — particularly running it fully “cranked” — an inspection by a qualified vintage Marshall technician is recommended, given its age and approximately four decades of collector ownership.

Key details

Marshall JTM100 “Black Flag” Super P.A. 100W
Approximate production period: 1966–1967
Serial number: SP/20761
Four input channels and eight input sockets
Tested and working flawlessly in its current configuration
Exceptionally well-preserved chassis and internal wiring, approaching near-new condition in many areas
Very good original gold Plexi panels, without cracks or additional drilled holes
Beautifully preserved black Tolex with authentic age-related patina
Approximately 40 years spent in a collector’s living room
Believed 100% original in its surviving components, including the fitted valves
Two EL34 output valves missing
Front Marshall script logo missing

Worldwide shipping

Worldwide shipping can be arranged without difficulty. The amplifier will be carefully packed for international transport.

Shipping insurance covering the full purchase value can be arranged upon request. The additional cost of this insurance is payable separately by the buyer and is not included in the advertised shipping charges. Please contact me before shipment if you would like full-value insurance arranged.

A rare opportunity to acquire a remarkably well-preserved early Marshall Black Flag Super P.A., combining an appealing collector history, working condition and an outstanding degree of originality.

Please examine all photographs carefully, as they form an important part of the description.