I offer you "Dynabortion 2". Hey - lets add a crap load of DC power storage to an ST-70 and also some heat sinks and a fan from a computer that works off sensors under the tube cage. Of course the fan and heat sinks block the vertical air flow - SO - that's why it needs a fan (catch 22?). I wish this fellow showed the interior wiring. I am sure it probably looks like it was wired by a wino on New Years Eve ..
The driver board uses four 6DJ8/6922 driver tubes and (apparently) has individual bias controls for each output tube. Anyone know who made this replacement ST-70 driver board ?
In case you missed "Dynabortion # 1" it is at the link below.
Dynabortion # 1