The Power Supply

The power supply is as much important as the circuit itself. It is the heart of any good planned amps. I used classical schematic of full-wave rectifier with Pi-filter (C-L-C). In my opinion tube rectification sounds better than silicon diodes one. Voltage drop across kenotron tube is not a problem, because single ended amp works in Class A and use the constant value of DC current.

For inductance coil I took Audio Note AN-160 choke with 10 Henry value. It looks solid and is bigger than Hammond models.

Filters input capacitor is very important for sound character of tube amp. I have changed film capacitor to paper-in-oil cap and was very surprised! This change brought the great improvement of the sound. I can describe it in two words: relief and gentle.

In power supply you can see hard to find (discontinued) japanese Elna Cerrafine 220uF 500V cap.