Thanks to Paul, pictures of an AC30 Twin from late 1963, chassis produced for JMI by Burndept, chassis number 1766 in the "old" position on top of the plinth (in front of the output transformer). Although no serial number plate survives, having been lost before or during the refurbishment of the cabinet, a serial number in the high 8000s is likely. From an electronic standpoint the preamp is untouched. For more on amps with serial numbers in the 8000s, see the main page here.

Of particular note - the presence of Mullard mustard capacitors. These were evidently used by Burndept at points in 1963 when stocks of WIMAs were not to hand.

Date codes

Woden transformers: "JU" = September 1963, with old-style part numbers 66310&J/83 (output) and 73218&J/82 (mains). The choke is unstamped.

Hunts main filter: "YSI" = 5th week of 1963.

Blue Hunts 25uf bypass caps in the preamp: "HUH" = 26th week of 1962, and "WII" = 13th week of 1963.

Mullard mustard capacitors: "A3S" and "B3S", respectively first and second quarters of 1963 for their manufacture. The "S" suffix is unusual, the normal suffix being "N" = the Blackburn factory. Where Mullard valves are concerned "S" = Barcelona factory, but that hardly seems likely in this instance. "S" suffixes are also found on the mustards in AC15 serial number 5049.

Pot codes: the tone pot has a single "K", standing either November or 1963, but not for both. AC30 pot codes normally have two letters, the first for month (A-M), the second for year, where "J" = 1962, "K" = 1963, "L" = 1964, and so on.

Speakers: Celestion blue T530s, one reconed in 1970, the other with "06FH" = 6th June, 1963. It may be that these were the originals, but as the wiring has been renewed, it is not possible to be wholly certain.

Valves: renewed in the 1970s with new label Mullards, the ECC82 with date code "B2K1" = 1st week of November 1972.

The latest elements in the amp (definitively known at present) are the Woden transformers.

Exteriors and upper chassis

Preamp

Speakers

One was reconed at the Celestion factory in December 1970, the date ( MC10) stamped in black on the frame; the other has its original gasket, date cod "06FH" = 6th June, 1963. The end bells of both have been removed and re-bolted in such a way as to present the VOX labels at an angle rather than horizontal. The terminals of the speakers are in their normal orientation.

Further elements

The body of the footswitch has been replaced but the cable is the original JMI coaxial (bought in from Permanoid). The original vinyl was evidently black basketweave.