02-10-2013, 04:58 PM
(02-10-2013, 11:00 AM)Bushbaby Wrote: I am proposing to revert this amp to the black faced (bf) spec which is to drop the 40uf cap to the rectifier valve to 22uf (nearest to 20uf). The bf version operated at 50v lower at the rectifier...
(02-10-2013, 01:42 PM)pwdrive Wrote: So far as I am aware the difference in the HT between the two is due to a different mains transformer, one gives out 315 volts ac under nominal load and the other gives out 365 volts ac under nominal load...
I'm not at all familiar with guitar amps, but looking at the circuit which seems a fairly standard output stage I have got to agree with Lawrence's comment.
Simply changing a reservoir capacitor by itself for one half its specified value is not going to drop the HT by 50 volts. The difference between the circuit diagrams of the two amps is far less "subtle" than it appears I'm afraid.
Regards
