In older post I wrote that long time ago I built my first tube amp. Today, in old magazine, I found the schematics. As I remember, the output stage was working, but I made some mistakes in pre-amp. I left amp for very long time and my mother decided that it was junk and threw it away. 🙂
Recommendations for sound quality improvement: remove C9, C10 and C11. Change R2 to 240K, add feedback from output via 10K (R16) to Ð›1Ð± cathode (dashed line in the circuit diagram).
Output transformer: Ð¨ form core. Size of the core is about 4cmÂ². Primary 2500 turns ÐŸÐÐ› 0.16 mm wire, secondary- 75 turns of ÐŸÐÐ› 0.8-0.9 mm wire. Output power ~3W, output resistance 4.5-5 Î©.
Tubes: Ð›1 – 6Ð2ÐŸ, 12AX7; Ð›2- 6ÐŸ1ÐŸ (miniature analog of 6ÐŸ6Ð¡ = 6V6!, maybe 6AQ5?)
Schematics from Ð Ð°Ð´Ð¸Ð¾ 8, 1967.