Preamp schematic universal tube 12ax7 phono circuit supply power 4s bias simple tubes cascade reyhan 6 tube stereo pre The “universal” preamp
The “Universal” Preamp | Cascade Tubes
Secondary 20k transformers 50k usable primary
Schematic Tube Preamp
Tube stereo pre amplifier preamp schematics audio power valve vacuum transformer radios circuits electronic secondary list 5a 500v 117v ct Are this transformers usable (z primary 5-20k / z secondary 12.5-50k)