The AC30TB and AC30TBX survived in the Vox line for ten years.Near the end of the run in 2003, escalating manufacturing costs caused the retail price of the AC30TBX to reach 00.
Built like a tank, the JMI AC-30 was hand wired on tag strips fastened to a sturdy steel and aluminum chassis.
By early to mid 1965, Burndept Electronics, which shared a building with Vox off West Street in Erith, Kent, took over the bulk of production, and serial numbers consequently become more reliable as a means of dating - Burndept was a much more orderly place than Triumph.
It should be said, however, that the Burndept chassis numbers stamped on the aluminium upright underneath the input jacks do not run in sequence with the serial numbers: Valve rectified AC50 - note the three main valves from left to right, the GZ34 rectifier, and two EL34 output valves. Amps produced for Vox by Triumph Electronics do not have chassis numbers.
Top, serial number 1524, small box; underneath it serial number 1411, large box. 6023 - front left by the mains transformer, and the tell-tale chassis pass-through hole behind it.
The very earliest of these amps have link voltage selectors. After that, we have the later style of dome selector: 1965 and on - GENERAL OUTLINE. Naturally, if the AC50 has a brimistor, or has the chassis pass-through hole for one (brimistors were often removed), we have a rough terminus post quem for the amp.