1930's classic ST tube plays wonderful stereo sound!

A project log for Vacuum tube game in 21st century

Playing vacuum tube is not so difficult as expected. Let's play great heritage of human being by modern technology!

kodera2tkodera2t 07/16/2019 at 09:280 Comments

Previously I've presented mono power amplifier using classic ST tube, type 19. Indeed I was so fascinated its wonderful sound (far wonderful than I expected), and this time I made two channel, stereo power amplifier. Basically the circuit is the same as before, just repeating twice. Its heater voltage is generated by switching regulator (tiny AC/DC adaptor), and plate voltage is generated just rectifying AC100V. So no power transformer but just one choke coil. You can see the rest 4-transformers, the input trans is BOGEN T725 between white-violet-black and violet is used for centre tap for tubes. The output trans is tiny 0-7-12k to 8 ohm, it is apparently not centre tap but it is working. (not ideal operation, but working well).

Actual operation can be found in the following movie... Have fun!