The UL Bassman amps are not particularly revered and get an undeserved bad rap IMO. Most people point their finger at the UL output transformer. The UL OT is not the problem. The CBS engineers added the UL transformer to Fender circuits with existing negative feedback loops and also added implemented a voltage doubler power supply that pushed voltages to or passed the limits for 6L6GC tubes. In addition to the aforementioned changes various tone sucking shunt capacitors were implemented in the circuit as band aid fixes to address oscillations in the circuit caused by sloppy wiring. The purpose of this thread is to explore circuit mods to address some of these problems and explore amp voicing options. I have been bitten by the Hiwatt bug lately and was thinking of modding a UL Bassman circuit to provide one channel with Hiwatt voicing and the other channel with Fender voicing. The Bassman 70 platform with the third preamp tube offers the possibility of cloning amid 70s Hiwatt preamp in one channel and an AA864 Bassman preamp on the other.