To give this amp a more responsive tone, I converted the preamp to a classic AC30TB circuit and removed any extra loading on the signal.
I increased the power amp supply filtering a bit and disconnected the "smoothing" switch, which I converted to a solid-state circuitry bypass switch. Now when the switch is set to "modern," reverb and tremolo are completely removed from the preamp circuit.
I also replaced the stock output transformer with a custom Dynaco a-470 variant wound by Heyboer.
With some good preamp tubes and a quad of 70's Russian EL84s installed, the amp sounds great through its 2x12" cab loaded with two Weber Alnico speakers, a Silver Bell and a Blue Dog.
