The Vox AC line

Dating & notes

This is the corpus's first family outside the Fender and Marshall lines, and its dating rests on a different kind of evidence: JMI's own works drawings are numbered and dated in their title blocks, so the AC15 and AC30 revisions can be pinned to a day where the Fender tweeds can only be bracketed by chart revisions. They also carry running modification boxes, which is why the AC30/6 appears twice above: one sheet, two circuits, separated by the list of changes of 8 May 1961 that took the EF86 out of the Normal channel. JMI issued the same circuit in three voicings — "Normal" (drawing OS/065), "Treble" (OS/056, dated 10 September 1964) and "Bass" (OS/057, 11 September 1964) — differing only in a handful of capacitors and, on the Treble sheet, in V1's cathode circuit; the Normal sheet is the one documented here. Two honest gaps remain. The first AC15's introduction is given as late 1957 by the Vox history archive and early 1958 by the general reference used here, and no drawing has been read that settles it. And accounts of the earliest AC30 output stage disagree, so the 1959-60 AC30 row above claims wattage and years but no valve complement. Two circuits in this line now have documented entries in the corpus — the third AC15 circuit and the post-1961 AC30/6 "Normal" — and every other row is history-tier until one is built.