While the AC-4 was introduced in 1962, “The Vox Story” by Dick Denney and David Petersen reports that the “TV front” AC-2 was first offered in 1958. In his book, Denney recalls that the earliest design for the AC-2 had a 6.5″ speaker. Denney indicated that the speaker size was increased from 6.5″ to 8″ due to poor sales of the AC-2 with the smaller speaker.
In 1960, without any changes to circuitry or power output, Vox renamed the amp the AC-6 to suggest the peak RMS power of the amp.
In 1961, the TV front cabinet styling of the AC-6 was replaced with what what now be known as “traditional Vox styling” and the amp name went back to AC-2.
The AC-2 electronic circuitry is documented on Jennings Musical Instruments schematic OS/009, dated 9/12/61. The amp is included as the AC-6 in a 1960 JMI Vox double sided sales flyer and as the AC-2 on page eight of a 1961 JMI Vox Amplifier catalog.
The AC-2 (and in 1960, the AC-6) would accompany the AC-10, AC-15 and the AC-30 to form a complete Vox amplifier range.
Cosmetically, the 1961 AC-2 had fawn vinyl, brown diamond grill cloth and brass vents, as seen in the photo at upper left. Electronically, the AC-2 had four tubes: one EZ80 rectifier, one EL84 power tube, one ECC81 (aka 12AX7) and one EF86. The amp had two inputs and three rotary controls: volume, tremolo speed, and a tone control that included an on/off switch. A control panel voltage selector plug also housed the mains fuse. A single button tremolo foot switch was included with the amp.
The 3 ohm 8″ speaker in the AC-2 and AC-4 was manufactured by Elac in Germany.
In 1962, the AC-2 was renamed the AC-4. The new name might suggest an increase in output power, but this was not the case. In reality, the AC-4 had the same circuits and power output as the AC-2. The original power output of the AC-2 was about 3.5 watts RMS (6 watts peak), so JMI chose to rename the amp to AC-4 to reflect the actual power output. After a small handful of very minor electronic revisions, a new service schematic, JMI OS/051, dated 9/25/64, was drawn for the AC-4.
The amp shown at lower left is shows the AC-4 in “mid 60’s” cosmetics. It was covered in black “basket weave” vinyl and had brown Vox grill, a hinged handle, and two metal cooling vents