Single-Ended 807 Amplifier
This amplifier was built on-the-cheap. I used salvaged transformers purchased well below online prices and 807 tubes which are still reasonably priced. 7 watts per channel. I won an impromptu local “shootout” with this. Recently added speaker/headphone switch and headphone jack. Now it’s personal!
How it was done: Single-ended pentode mode, with primary-side feedback, and fixed bias operation.
A look at the construction:
Just wondering why you didn’t use a bypass capacitor on the cathode of the 807.
Ah, look again! It’s a fixed bias circuit, not cathode bias. The 10 Ohms are present for allowing the current level to be measured (50ma = .5V). Very little degeneration at 10 ohms, bypass isn’t needed. Ignore the schematic comment, it’s .5V not .05V.