Any low voltage tube schematics?

[Dud]

also here

Tubes for Synthesizers

Hi all! It’d only be appropriate to write a tutorial on tube theory as I understand it for synthesizer enthusiasts. I’ll add more circuits as I go. Also, I say “tube” because I prefer the sound of it to “valve”, even though I’m Australian IMPORTANT! Tubes are usually always designed to operate at a high voltage, and it’s a lot easier to run them off mains electricity. I design my circuits around a 250V DC power supply, which gives quite a bite if you touch it! I initially had th…