Early Burndept chassis - strays (original cabinets lacking)
Late 1962
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On this page, an overview of AC30 chassis assembled by Burndept Electronics for JMI in late 1962 that were no longer with their cabinets when they were sold. The AC30s from which they came will have come originally have had serial numbers in the higher 5000s, beginning around 5600 - examples can be found on this page.
In all likelihood, the examples in view below will by now (November 2025) have been rehoused in new cabinets, or at at least cabinets acquired from other sources, speakers probably from another source again - all perfectly understandable, as a chassis on its own is fairly useless. As most of the strays that come up for sale are normally readily identifiable (from distinctive patterns of wear and tear), it is a fairly simple thing to match sets of pictures up ("befores" and "afters").
One of the hallmarks of the chassis represented is the presence of Woden transformers with date codes "HT", "JT", and "LT" - August, September, and November 1962. No example has come to light so far of a standard production AC30 with a Woden dated "KT" (October 1962). The page on Woden transformers is here.
For the time being, chassis with transformers dated "MT" - December '62 - have been excluded. There is absolutely no guarantee that they were assembled in that month.
That Burndept normally gave its chassis serial numbers (numerical sequence beginning at 1000) has long been known - see the picture at the head of this page. Stamped on the bare chassis prior to population with components, these were added solely for administrative purposes. Chassis were taken up in no particular order thereafter for assembly / population on the work-benches. That said, it is possible to detect general patterns within batches, certainly where 1962 and earlier 1963 are concerned.
It should perhaps also be noted that finished chassis could be - and generally were - weeks old by the time an amp reached the point of readiness for sale. Of all the elements embodied in an AC30 (electronic or otherwise), speakers consistently have the latest date codes - for an overview, see this page.
Various pages relating to Burndept, including the ones linked above, have been gathered together on this index page.
Stray Burndept-made chassis
Woden transformers with August 1962 date codes ("HT")
Chassis number 1050
Chassis no. 01050; Woden transformers and choke with the date code "HT" = August 1962. The preamp has been extensively redone, resistors, capacitors, and pots.
Chassis number 1053
Chassis no. 01053; Woden transformers and choke with the date code "HT" = August 1962. The tone pot has "IJ" = September 1962 for its manufacture. The Top Boost unit is a later addition - Mullards with 1964 date codes and pots with "AM" = January 1965.
Woden transformers with Aug. and Sept. 1962 date codes ("HT" and "JT")
Chassis number unknown
Chassis number unknown at present; the Woden mains tranformer and choke have the date code "HT" = August 1962; output transformer "JT" = September 1962. In the preamp, the Hunts main filter capacitor has "ITH" = 34th week of 1962 for its manufacture; the 25uf bypass caps have "HHH" = 22nd week of 1962. The date code of the tone pot is "HJ" = August 1962.
Woden transformers with November 1962 date codes ("LT")
The printing on the shroud of the output transformer is now in the same orientation as that of the mains transformer.
Chassis number 01291
Chassis no. 01291; Woden transformers dated "LT" = November 1962 for their manufacture. Underchassis, the Welwyn ceramic resistor has "TJ" = Sept 1962. In the preamp, the small blue Hunts 25uf electrolytics have "HUH" = 26th week of 1962; and the main Hunts filter cap has either "YIH" or "TIH" = 13th or 43rd week of '62.