Karel-Mars Hi Ampland ? I have a nice project on my bench: a VOX AC30 that needs to be made studio ready. As it is, it plays (and sounds beautiful), but there is a lot of noise and crackles. Confusingly, the serial number on the back (#18069 - AC30 B) does not match the chassis number (#13763 - AC30/6). Anyone has an idea which one should be the correct one?
matta Hey Karel, The B stands for Bass Model, originally made for Bass Players, there was also a T, or Treble Model, which I own. 1 out of 3 AC30's built in the JMI era were T models, making it fairly collectible, though rather bright for Rhythm playing and was better suited for lead playing, cutting through the mix etc. Then of course there is the standard N, or Normal model. ALL three models are AC30/6's, just voiced differently. The main differences between a B and N model is that the B model has a larger cap on Anode of Triode 1 of V1 (C2), a Bass model has a 0.1uF cap, a Normal a 0.47uF and a Treble a 0.047 on the 'Bright' channels. Also the caps are different on the Anode of Triode 1 of V2 (C9), 'Normal' channel , 0.15uF on a Bass model, .15uF an Normal model and 0.047uF on a Treble model. Also C10 on the Tone Cut Control is 0.01uF on a Bass model, 0.0047uF on a Normal model, 0.047uF on a Treble model. Just trace out those parts and it will tell you which model the amp 'REALLY' is ? The BACK plate won't match the chassis as they were sourced from different suppliers and regularly 'mixed up', which is part what makes dating Voxes hard as most of the info on JMI era amps was lost in a fire years ago, you just have to take your clues from date codes as well as cosmetic changes. Cheers Matt
vic Nice one Karel.......The ID plate- and chassis serial numbers are always different. The latter is taken for ID purposes for obvious reasons. This AC30 dates from early '67 (the Woden mains tranny is November 1966 and the choke is October 1966). Such a pity about the one replaced speaker.
