Woden transformer, date code "HW" = August 1965, in serial number 20750.

This page picks up from the page on AC30s with serial numbers in the 19000s.

Control panels are grey. Dome voltage selectors occur as standard, as they are for amps with serial number in the 17000s and later. Chassis were assembled by Burndept, the contract with Westrex having ended in early 1965 following JMI's move (expansion) into Burndept's West Street Factory in Erith - the "West Street Works".

In late 1965 production began to slow. The European market was still strong, but fewer orders for AC30s came in from America. The Thomas Organ Company, which had the rights to the "Vox" name in the States, preferred to promote its solid state range.

The four models are still: "TB" for "Top Boost", designated "TB" on the serial number plate, the circuit's controls normally integral in the control panel; "Treble" designated with a "T"; and "B" for Bass. The two last had their own schematics, in order: OS/056 and OS/057. "Normal" voicing no longer seems to be an active designation. Some notes on the treble circuit, which was new in 1964, can be found on this page.

Number plates with three lines - MODEL No., SERIAL No.. and RATING (power consumption) - come in in the high 20000s. Although chassis with chassis numbers stamped under the voltage selector (the older position) appear at points throughout the 20000s, most are of the newer type, the number now on the left-hand side of the aluminium preamp upright underneath the input jacks.

Woden transformers are the norm, year codes being "V" = 1964 and "W" = 1965, the first letter in the two-letter sequence standing for the month: "HW" = August 1965 for instance. Chokes are often the gold-coloured type - also used by JMI for the AC100 - stamped with the part number 66429.

Silver alnico T1088s are standard. In mid 1966 Celestion revised the design, introducing a dedicated board for the solder terminal between the spokes of the frame. Earlier T1088s have terminals on the frame itself. An overview of "silvers" (really "poly grey") can be found on this page. Grille cloth in the 20000s is normally black. Plastic corner protectors have single pins through to the low 21000s.

Note that the majority of serial numbers of amplifiers in the range cited by Jim Elyea - listed in his book and noted in the sections below - end in "0". How can this be? The suspicion is that at least some of these are simply placeholders and guesses: i.e. "serial number 21410 will have been reached at June 1966".

If anyone knows of further amps that should be incorporated on this page, do let me know.

Serial number 20017 TB - currently in the UK

Top boost in panel. A number of replaced control knobs. No shots of the electronics at present.

Below, pictures of the serial number plate sold separately in 2022, probably indicating that the amp has been parted out.

Serial number 20139 TB

Grey panel, integral Top Boost. Chassis number in the 11000s - 11353 (?) Albion mains transformer; Woden output date code "EW" = May 1965; gold-coloured choke (as used in AC100s) stamped 66429. In the preamp, Mullard caps with date code "B4N", "C4N", and "D4N" = second, third, and last quarters of 1964. The grille cloth is 1970s Rose Morris. The front was regrilled with cloth from another Vox amp by a subsequent seller.

Serial number 20150

Listed by Jim Elyea, but probably simply as a a "marker" number, not a known amp.

Serial number 20157 - currently in Sweden

Good cosmetic order. The speakers are Celestion blues, replacements for the original silver T1088s.

NEW

Serial number 20183 TB - currently in the UK

Chassis number 11929. Grey panel. Albion mains transformer; Woden output with "KV" date code = October 1964 for its manufacture; gold-coloured choke, part number 66429. In the preamp, visible Mullard mustards with "B/64", "C4N" and "D4N" = second, third, and last quarters of 1964. The original speakers look to be present, also the amp's original black cover.

Serial number 20203 T

Excellent condition externally. Thanks to Lothar for the pictures.

NEW

Serial number 20206 T - currently in the UK

External shots only. Replaced grille cloth and speakers.

Serial number 20269 TB

Chassis number, stamped under the voltage selector, not quite readable. Transformers are Woden and Albion. The Woden (output) has the date code "KV" = October 1964. The choke (part no. 66429) is of the type used in certain fixed bias AC100s. In the preamp, a mixture of Mullard mustards, a number with "B4N" and "C4N" (= second and third quarters of 1964), and gold-coloured WIMA Tropyfoil (Tropyfol). Two of the TCC cathode bypass caps have "WC" = March 1965.

Serial number 20370 TB - currently in the UK

The serial number plate alone, sold on ebay in the UK in November 2021.

Serial number 20388 TB - currently in the UK

Chassis number 12146. Woden output transformer with the date code "KV" = October 1964; and choke with "HW" = August 1965. The mains transformer is an Albion. In the preamp, Mullard capacitors with a spread of date codes for 1964 - "A4N", "B4N, "C4N", and "D4N" (first to last quarters of the year). In one picture the amp is shown with an orange cover which was sold to another dealer (and subsequently sold with a different amp).

Serial number 20400

Listed by Jim Elyea, but probably in the abstract (i.e. no details of component date codes known or even of the amp's existence).

NEW

Serial number 20433 TB - currently in Europe

External shots only. Cabinet intact, but electronics wholly redone.

Serial number 20442 TB - currently in Europe

Chassis number 12140. The preamp has a mixture of Mullard mustard and WIMA capacitors. No date codes visible.

Serial number 20447 TB

Possibly Woden transformers. One of the Celestion silvers has the date code "17HK" = 17th August 1965.

Serial number unknown - currently in Europe

Chassis number 12344. Chassis and speakers in a later cabinet. Woden output transformer "HW" = August 1965, mains transformer "JW" = September '65. A number of Mullard mustard capacitors have the date codes "B4N" and "C4N" = second and third quarter of 1964 for their manufacture. One - a later addition - gives C/71 (third quarter of 1971). The Celestion T1088s have the date code "11KK" = 11th October, 1965. The cabinet, covered in basketweave, has two lines of vents (ie. six in total), and probably belonged originally to an amp made at the Birch-Stolec factory in the early 1970s. Note the gap between the chassis and the top edge of the case. Thanks to Paul for the pictures.

Serial number 20523 TB - currently in Scandinavia

Voltage selector removed in conformity with Scandinavian electrical regulations. The Woden transformers have date codes "KV" and "JW" = October 1964 and September 1965. The stamping on the mains transformers has part of the old component code "J.82". The choke is of the type used in early fixed bias AC100s, part number "66429".

Serial number 20557 TB - currently in Scandinavia

Probably exported to Denmark early on. Voltage selector removed and a plaque fixed over the empty hole. The Celestion blues are likely to be later replacements.

Serial number 20565

Existence recorded by Jim Elyea

Serial number 20612 TB

Shots of the exterior only. "VOX" logo composed of single letters. Centre handle on top replaced. The original Celestion silvers look to be in place.

Serial number 20648 TB

Cabinet, chassis, and speakers offered for sale separately in July 2024, but subsequently sold as a complete amp. Chassis number stamped under the input jacks. The Woden transformers have the date codes "EW" and "HW" = May and August 1965; choke unknown. In the preamp, a mixture of WIMA and Mullard mustard capacitors. The speakers have the date codes "21DK" and "22DK" for their manufacture. Thanks to Chris for new info.

Serial number 20662 TB

In the preamp, a mixture of WIMA and Mullard mustard capacitors. The speakers may have been reconed.

NEW

Serial number 20669 TB - currently in the USA

Woden choke and output transformer with date codes "HW" and "LW" = respectively August and November 1965 for their manufacture. Rectification is now solid state, a printed circuit board (with diodes etc.) added later underchassis. Logo composed of single letters, as serial number 20662, above. Thanks to Greg for the info. and pictures.

NEW

Serial number 20671 TB - currently in the USA

External shots only.

Serial number 20675

Existence recorded by Jim Elyea

Serial number 20703 TB

The Woden mains and output transformers have the date code "KV" = October 1964. The choke has "BW" = February 1965. One of the silver speakers is a later replacement. The original cover is still present.

Three-line serial number plates from this point

Serial number 20750 TB

Thanks to Keith, photos of serial number 20750, bought in Queensland (Australia) in 1975. The Woden output transformer and choke have the date code "MW" = December 1965, the mains transformer "HW" = August '65. Preamp in good order. Speakers are now early Celestion greenbacks (Thames Ditton Works). In company with the serial number plate on the back panel, a JMI speaker unit plate.

Serial number 20770

Existence recorded by Jim Elyea

Serial number 20828 TB

As in the case of serial number 20831 below, a plate on an AC30 Super Twin cabinet.

Serial number 20831 TB - currently in Europe

Plate on an AC30 TB Super Twin.

Serial number 20833 TB - currently in the UK

Serial number 20840

Listed by Jim Elyea, but probably as a "guesstimate".

Serial number 20864 TB

Woden transformers with "EW" and "HW" date codes, respectively May and August 1965 for their manufacture. In the preamp, a mixture of WIMA and Mullard mustard capacitors, the latter with date codes "B4N" and "D4N" = second and last quarters of 1964. Chassis, speakers, and cabinet sold separately in 2024.

Serial number 20899 TB

Woden transformers (date codes unknown) and gold-coloured choke stamped 66429. The serial number is in the new position - on the left hand side of the chassis (under the input jacks). The original JMI warranty documentation and owner's manual are still present. The manual has the print date "11.65" = November 1965. Speakers are Celestion T1088s, the terminals still on the frame (rather than an intermediate board).

NOTE: - the documentation was sold separately in early 2024.

Serial number 20910

Listed by Jim Elyea, but probably as a "guesstimate".

Serial number 20965

Listed by Jim Elyea, but probably as a "guesstimate".

Serial number 20968

Serial number 20983 TB

No shots of the electronics. On the front of the grille cloth, the "TOP BOOST 30" runner is still present. Speakers are Celestion T1088s, terminals on the frames.

On to serial numbers in the 21000s.

Back to serial numbers in the 19000s.