I redid my ST70 with solid state rectification and VTA board. It sounds bad. I drug out my old Eico oscilloscope and looked at the waveform at 1000 Hz using my laptop generating the signal.
Bad alright, the sine wave appears like it is "missing" a line segment for probably 90 or so degrees. It is really not missing though, there is a much larger signal there at a much higher frequency.
I verified using another tube amp (not an ST70) with exact same connections and it is fine, good sine wave.
Also, the ST70 biases out good and does the same thing with both Sovtek EL34's and Westinghouse 6L6WGB.
I need to hook it back up tomorrow and trace out the signal and go from there...
In the meantime, any ideas?