Vox AC30: copper panels
(and some early grey)
Early to mid 1964: serial numbers in the 12000s
Serial number 12733 Treble, the plate still hand stamped.
Continued from the page on AC30s with serial numbers in the 11000s. Also encompassed below, Super Twins with numbers in the main AC30 sequence - Super Twins (and Super Twin Reverbs) by this point had a sequence of their own beginning at number 2500.
A good number of amps were apparently covered in thick, smoooth dark grey vinyl.
Throughout the 12000s one finds three models: the "Treble", designated with a "T" on its serial number plate; "Normal" voicing designated by an "N", and Bass designated "B". All three had their own schematics, in order: OS/056, OS/065 and OS/057. Some notes on the treble circuit, which was new in 1964, can be found on this page.
Documents relating to the AC30 in 1964 are being assembled here.
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 aluminium upright of the preamp chassis (normally on the right hand side a little way below the voltage selector):
Detail of serial number 9916. Chassis number 02607. The chassis number sequence began at 1000, but chassis awaiting assembly 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. Serial numbers in the 11000s (much as those in the 10000s) have date codes for late 1963 - "JU", "KU" and "MU" = September, October and December 1963; and early 1964 - "AV" and "BV", respectively January and February. JMI evidently ordered sizeable batches:
Serial number 12004 - output transformer date code is "AV" = January 1964; the choke has "BV" = February 1964.
The Woden part numbers were, in order: mains transformer 72318; 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. Dark brown Dubilier resistors are found along with white Eries.
From early 1964, most Twins have Burndept-made chassis; those produced by Westrex were generally alloted to Super Twins.
Cabinets are in the main covered in black basketweave vinyl, though "pebble" ("dimpled") vinyl was evidently used from time to time, and likewise smooth black or charcoal vinyl. Back boards as a rule now have radiused corners rather than square.
Speakers in "standard" AC30s continue to be the Celestion blue (alnico magnet, Celestion part no. T530) - date codes in mid 1964, the final "H" in the code can indicate 1963 or 1964. The preceding letter is always the month (A-L).
Serial number plates are still hand stamped.
If anyone knows of further AC30s that should be incorporated on this page, do let me know.
Serial number 12004 - currently in Europe
Copper panel; smooth dark grey pebble (dimpled) vinyl. Date codes of the Woden transformers are "AV" = January 1964, and the choke "BV" = February 1964.
Serial number 12019 - currently in the UK
Chassis number 04690. Albion transformers. A mixture of Mullard mustard and WIMA capacitors in the preamp. The Mullards have date codes "D3N", "A4N" and "14N" = last quarter of 1963, and first quarter of 1964. Grey panel with integrated top boost. The stamping on the serial number plate (which looks genuine enough - i.e. not a repro) is abnormal.
Serial number 12022 T
Simply the plate, evidently detached from the amp some time ago.
Serial number 12238 N - currently in the USA
Existence known from an old "Plexi Palace" forum thread. The amp was described as having a copper panel and integral top boost.
Serial number 12253 (?) - currently in the UK
Chassis number 04866, now in a later cabinet. Although the serial number plate is a repro, it may carry the amp's original number - 12253. The chassis certainly belongs in the 12000s. Visible in the preamp are mustard capacitors with the date code "A/64" = first quarter of 1964. The transformers are Albions. Thanks to Michael for the pictures.
Serial number 12300
Existence noted by Jim Elyea.
Serial number 12333 B - currently in Italy
A Super Twin, amplifier section and speaker cabinet, the BASS flag still present on the front grille.
Serial number 12405 TB - currently in the UK
Grey panel with integrated top boost controls. The cabinet covered with thick grey vinyl. Double pin corner protectors added later.
Serial number 12411 T - currently in Europe
Chassis number 04551. Assembled by Burndept. Grey panel, integrated Top Boost. Albion transformers. One of the Mullard mustard capacitors has the date code "D3" = last quarter of 1963; and another has "A/64" = January 1964.
Serial number 12501 N - currently in Europe
Chassis assembled by Westrex (most Westrex-made chassis were allocated to Super Twins). The Woden mains transformer, likely to be a later replacement, has the date code "EW" = May 1965.
Serial number 12543 B - currently in Europe
Basketweave vinyl. Currently here.
Serial number 12549 - currently in Europe
Thick smooth dark grey vinyl. Currently here.
Serial number 12563 N - currently in the UK
Sold on ebay some time ago - an AC30 serving as a PA amplifier with two LS40 speaker columns.
Serial number 12569 N - currently in the UK
Basketweave vinyl. A rare instance of a copper panel Twin with integral Top Boost (bass and treble) controls. Chassis assembled by Westrex; Albion transformers. The choke may be a replacement, its sticker stuck to the output transformer. One of the gold-coloured TCC cathode bypass caps in the preamp has the date code "UF" = June 1963. Inscribed above the speaker output block is the number "165", which is found on other chassis assembled by Westrex (an AC80/100 and two other AC30s). Thanks to Ben for the pictures.
Serial number 12588 TB - currently in the UK
Top Boost in panel. The cabinet has dark grey textured vinyl. Thanks to Malcolm for the photo.
Serial number 12589 TB - currently in the UK
Grey panel, top boost controls integrated. The JMI logo on the panel is standard format, not as the one on serial number 12019 (above). Transformers are Albions. Mullard mustard capacitors in the preamp have the date codes "D3N" and "14N" = last quarter of 1963 and first quarter of 1964.
Serial number 12635 N - currently in Europe
An instance of a Super Twin with a number that would normally be reserved for a Twin. The voicing is given as Normal ("N"). The cab was said to contain "silver bulldog" speakers - ie. Celestion T1088s.
Serial number 12733
Thick smooth dark grey vinyl.
Serial number 12787 B - currently in Europe
Chassis number 04851. The Mullard mustard capacitors have date codes "A/64" and "B/64" = first and second quarters of 1964. Thick smooth dark grey vinyl on the cabinet. Corner protectors added later.
Serial number 12850
Existence noted by Jim Elyea.
Serial number 12xxx N - currently in Japan
Another Super Twin, normal voicing. Transformers are Albions. The chassis is likely to have been assembled by Westrex.
Serial numbers unknown
Currently in the UK
The position of this amp here is tenuous. It could on the face of things be an early grey panel. Transformers are Albions. The TCC cathode bypass capacitors in the preamp have the date code "UC" = March 1963. The chassis, unusually for a Twin, was assembled by Westrex. It may be necessary to move this entry in due course.
Currently in the USA
Chassis number 04530. Dimpled dark grey vinyl. Double in corner protectors added. The chassis is grey panel with integral top boost. Visible Mullard mustard capacitors in the preamp have the date code "14N" = first quarter of 1964. One of the original speakers has been replaced with a modern Celestion blue.