This THD Univalve guitar amplifier is a single ended guitar amplifier that can use different output tubes. It has an Octal, and a Noval tube base. It can use a plethora
of tubes. Octal tubes include: EL34, 6L6, 6V6, KT88, and any of these types of tubes with the same pin out. The Noval socket is for the EL84 tube (6BQ5).
The amp also has a half power switch that works by altering the cathode bias resistor. This got me wondering if all these different tubes would bias correctly, on both full power and half power. I decided to do some testing on this amp.
The videos below are the results of those tests. Sit back and watch the video to see what we discover about this amp. One thing I did discover is that this amp sounds
amazing when using a KT88 tube. And we give this amp a demo using quite a few tubes in the video.