1965 and 1966

AC50s with Reverb

Below, the circuit of the JMI add on reverb unit - schematic OS/075.

Click to enlarge

Given the mention of the "Vib" channel, it is clear that the unit was originally intended for the Vox AC30 - but not exclusively. As the pictures below indicate, it was fitted to a small number of AC50s too. Since the reverb and its controls fit so well on the large box "shelf", use with an AC50 must have been envisaged from the outset.

It is probably no coincidence that schematic OS/075 is so close in sequence to the new schematic for the AC50 mark 3 - OS/072.

Although precise details are lacking, the units could presumably just as easily have been retro-fitted - by JMI or a dealer - as ordered specially.

Valve rectified amps

Serial number unknown - currently in the USA

Solid state rectified

Serial number 4108 - currently in the USA

Serial number unknown - currently in the USA