Just to give a little more point to a peculiarity of AC30/6 chassis produced in late 1961 and early 1962. Some, if not all, have a "phantom" hole for the rectifier valve, wrongly positioned. A blank disk of metal was welded in to seal it up. The two extraneous screw holes for the valve base surround were left unfilled. AC30/4 chassis do not seem to have this peculiarity.

In terms of serial numbers, the span is from AC30/6 number 4763 (black panel) to number 5002 (copper panel).

Whether every amp in this range has or had the phantom hole is not known at present. Approaching 250 would be fair number to get wrong. Perhaps it was a particular chassis bender who made only certain batches.

Serial number 4763.

Serial number 5002.

On to AC30s with serial numbers in the 6000s .

Back to AC30/6s with serial numbers in the 4000s (black control panels).