lately my '65 reissue deluxe reverb has been having problems with the vibrato channel. it will only work when the intensity is turned up to 10, but as the intensity is turned up, the volume drops at the same rate, so that when the vibrato is engaged, i'm only getting about 20% of the normal volume. any ideas? thanks!
It could be something as simple as a pre-amp tube. You could try buying one pre-amp tube and swapping out your preamp tubes one by one, to see if you can isolate an offending tube. If this doesn't work, I'd take it in to have it looked at by a reputable tech.