In 1960, Vox replaced the AC-30/4 with the AC-30/6. The 1963 AC30/6 "Bass" model amp shown at left belongs to Andy Wolf of Savage Audio in Burnsville MN.
History of the AC30/6 - The AC30/6 was produced in four different versions, as documented by Vox service schematics for the amp. JMI Vox schematic OS-056 depicted the "Treble" version of this amp. Schematic OS-057 was the "Bass" version, and OS-065 was the "Normal" version. The final version was the "Top Boost " version, which added separate bass and treble controls to the "Brilliant" channel. This model was depicted by a combination of JMI Vox schematics OS-065 and OS-010.
Early "Top Boost" models had these controls mounted to a recessed plate in the upper back of the cabinet. Later versions moved the treble and bass controls to the main control panel.
The electronic differences between the AC-30 Treble, Bass and Normal amps are extremely minor. The values of only two tone voicing capacitors, C3 and C10, are affected.
AC-30/6 Bass Amp - As a bass amp, the AC-30 leaves a lot to be desired. By the time this amp was produced in 1963, Vox was developing several amps built particularly for bass, the T.60 and the Foundation Bass.
There is an interesting story regarding the smooth black vinyl Vox installed on this amp. Prior to 1962, Vox amps were commonly covered in fawn (tan) vinyl. After the introduction on the Vox Continental Organ in 1962, many customers requested that their Vox amps be covered in the same smooth black vinyl to match the new portable organs. Once the overwhelming customer acceptance of this new and handsome color combination was measured, Vox phased out the fawn vinyl on their amps. This smooth black vinyl was installed on a portion of Vox amps manufactured in 1962 and 1963. Both the fawn and smooth black vinyls were eliminated in late 1963 when Vox changed to a black basket weave pattern vinyl.
The addition of one pin corners, black vinyl handles with the Vox logo, and black cast metal vents on an amp with "smooth" vinyl would seem to point to a 1963 birthdate for this amp. Prior to 1963, leather handles, brass vents, and no corner protectors would be common.
A small "BASS" model flag was affixed to the lower right corner of the grill.
Two 12" 15 watt Celestion/Vox Alnico Blue speakers were installed in AC-30s from this period. The wire lugs for these speakers were mounted in holes drilled through the frame. Later Celestions Alnicos would have the connecting lugs mounted to a cardboard tag strip riveted to the frame.