LARGE BOX AC50s - SOLID STATE RECTIFIED

AC50 Mark 3 (Mk III)

Serial numbers in the 8000s - 1967 and 1968

Amps assembled at the Vox Works / Burndept factory (always the presence of the stamped chassis number). American-style logos.

The band "influention" with a late large box AC50 (note the logo) on top of a Super Foundation Bass speaker cabinet.

The external characteristics of these amps are much as : American style logo at front, two-pin corner protectors, Amphenol connectors on the back panel. The only major difference is the regular appearance now of the white warning plaque.

Internally: amps begin to have more and more components used in the solid state amps: yellow Dubillier coupling caps in the preamp, and small Radiospares potentiometers. CCL capacitors had already been brought in by around serial number 7400.

It is also worth noting that cathode bypass caps are dropped for the preamp valves (V1 and V2).

Above details from serial no. 8168. First pic showing one of the small pots in the preamp (the same type as in the early solid state amps). The second pic showing two of the yellow Dubillier caps. For examples of the Vox solid state amps, .

1968

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By serial number 8168, however, we are already well into 1968: the CCL filter capacitors are dated "B8" = February 1968. An outline of the CCL codes .

In the left-hand capacitor, one can only see the name "CCL". At right though, we have the date code "B8".

These late amps were produced close to the end of Jennings Musical Industries (in mid 1968). For the emergence of "Vox Sound Equipment Limited" (VSEL), which took over from JMI, on the Vox Supreme website. AC50s issued by "Vox Sound Equipment Limited" are .

Below, a register of amps. If anyone knows of others that have not yet been included, as ever .

Serial number 8043 - currently in Europe

Regrilled in brown cloth and a new logo added.

Serial number 8063 - whereabouts unknown

Serial number 8091 or 8097 - currently in Europe

Serial number 8106 - currently in the USA

Serial number 8108 - currently in Europe

Serial number 8110 - currently in the UK

Serial number in the 8000s - whereabouts unknown

No serial number, but chassis number 4076. One can just see in the second picture one of the red CCL capacitors. Its date code appears to be "C7" = March 1967. As in the case of amps on this page, there are no cathode bypass capacitors for the preamp valves.

Serial number in the 8118 - currently in the UK

The back panel slightly rejigged, but otherwise in good order. The serial plate still states "Vox Amplifier". Pictured with a Vox 2 x 15" cab from late 1964. For other early examples of what was later called the T100, see this page. Thanks to Matt for the pictures. Amp and cab may soon be for sale.

From this point serial number plates are headed "AMPLIFIER" rather than "VOX AMPLIFIER"

Serial number 8153 - currently in Europe

Chassis number looks like 42xx. A replaced output transformer but otherwise in good original condition. The brimistor is still in place. The bias potentiometers are of the type used in the Vox solid state amps.

Serial number 8168 - currently in the USA

Chassis no. 4232. The CCL filter cap has the date code "B8" = February 1968. The preamp has yellow Dubillier capacitors and metal fixing plates for the pots (both found in Vox solid state amps).

Serial number in the 8100s / 8200s - currently in Holland

A late AC50, serial number in the 8100s or 8200s. White warning plaque on the back panel, serial number plate stating "AMPLIFIER" rather than "VOX AMPLIFIER". The preamp has been recapped. Servaas Muziekhandel in The Hague was a major outlet for Vox in the Low Countries in the mid to late 1960s - see this page.

Serial number in the 8000s

This amp is here because it has no cathode bypass caps. Amps with numbers in the 7000s seem to have them. Note the presence of the doubled up red CCL main filter caps on the upper chassis.

Serial number unknown

Chassis no. 4071. No serial number plate, so the amp's position here is not absolutely certain. However, in company with the amp above, number 8178, there are no cathode bypass caps in the preamp. The pots have the date code "EN" = May 1966. Thanks to Misha for the pictures.

Serial number 8178 - currently in Germany

Very probably issued with the solid state Foundation Bass cab which accompanies it.

NEW

Serial number 8209 - currently in Germany

One of a number of late AC50s exported to countries in northern Europe.

Serial number 8211 (or 8231?) - currently in Europe

Serial number 8219 - currently in the USA

Chassis no. 3422. New grille cloth and replaced logo.

Serial number 8270 - currently in the UK

Chassis number 4374. Dormant for some years, the amp has been has been expertly restored. Note that the paper labels on the undersides of the transformers have inspection stamps. The bias pots between the EL34 power valves are of the type used in the Vox solid state amps. Thanks to Rich for pictures and details.

Serial number 8297 - currently in Australia

A late JMI AC50, probably one of the last to be made, along with a beautiful collection of Rickenbackers. Thanks to Kieren for the pictures.

Serial number in the 8000s - currently in Australia

Chassis no. 4282. The CCL filter cap has the date code "B8" = February 1968.

Serial number probably in the 8000s - currently in Denmark

Serial number probably in the 8000s - currently in Spain

Pictured with a re-grilled Dynamic Bass (solid state series) cab.

Serial number probably in the 8000s - whereabouts unknown

Serial number probably in the 8000s - whereabouts unknown