Vox AC30: copper panels

Later 1963: serial numbers in the 8000s

Serial number 8739.

In progress, Mar. 2020

Continued from the page on AC30s with . Amps below, however, are mostly covered in new black basket-weave vinyl. Those in the 7000s have "dimpled" or "pebble" vinyl.

In mid 1963, the value of the cathode bias resistor was reduced in a move to run the EL84s harder and to squeeze a little more power from the circuit. The note added to schematic OA/26 on 14th June 1963 states that the change was from 80ohms to the 50ohms noted on the newly-drawn sheet.

In actual fact, one often finds original green Welwyn wirewound 82ohm or 47ohm resistors instead of the values specified.

Vox contracted out the assembly of AC30 chassis to two companies: Burndept Electronics in Erith, and Westrex in Dollis Hill (north London). A sure sign of production by Burndept is the presence of a stamped serial number on the chassis in front of the output transformer, or on the aluminium upright of the preamp:

Detail of serial number 6097. Chassis numbers begin at 1000, but they were not used in any particular order.

Also indicative of production by Burndept at this stage is the presence of Woden transformers with handsome green shrouds. The earliest batches date from autumn '62 (date codes "HT" and "JT"). Serial numbers in the 8000s have date codes for 1963, the letter for the year being "U".

On the Woden choke above (in serial number 8739B), "66311 & J/84" is the Jennings part number (for re-ordering). The transformers were specially made for JMI and do not figure in amps made by other makers. The date code is "JU" = September 1963.

The Woden part numbers were, in order: mains transformer no. 66309; output transformer no. 66310; and the choke no. 66311.

A good indication that a chassis was assembled by Westrex is the presence of Albion tranformers and dark brown Dubilier resistors - see for instance serial number 8648, below.

Cabinets are for the most part covered in new black basketweave vinyl. Back boards as a rule now have radiused corners rather than square.

Speakers continue to be the Celestion blue (alnico magnet, Celestion part no. T530).

Serial number plates are still hand stamped.

The page on AC30s with serial numbers in the 6000s, , and the page on serial numbers in the .

If anyone knows of further early copper panel AC30s that should be incorporated on this page, .

Serial number 8005 N - whereabouts unknown

Serial number 8177 N - currently in the UK

Top Boost added on the back panel at factory. Pebble (dimpled) vinyl.

Serial number 8190 - currently in the USA

Existence recorded by Jim Elyea.

Serial number 8269 B - currently in the USA

Disparate images. It may be that the first three are not of this amp. The output transformer is a later unit - the Woden date code is "KV" = October 1964. One of the potentiometers in the fourth picture has the code "FK" = June 1963, which is in keeping with the serial number.

NEW

Serial number 8274 N - currently in the UK

Original red vinyl. Albion transformers, the mains replaced.

Serial number 8287 - currently in the UK

Known from a clip on youtube. The vinyl has been removed from the cabinet.

NEW

Serial number 8368 - currently in the USA

Serial number 8540 - currently in the USA

Existence recorded by Jim Elyea.

Serial number 8616 B - currently in the UK

Simply the serial number plate.

Serial number 8648 - currently in Europe

Excellent condition. Assembled for Vox by Westrex. Albion transformers; brown Dubilier resistors. Top boost on the back panel - also a plaque recording the servicing of the amp by Dick Denney in 1994.

Serial number 8739 B - currently in the USA

The chassis probably assembled for Vox by Burndept Electronics. White Erie resistors; Woden transformers with date code "JU" = September 1963. Brass vents still on top of the cabinet.

Serial number 8920 - currently in the USA

Existence recorded by Jim Elyea.

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