Finally had time to try this circuit out today. Decent sound, not to bad. After checking out some tube data, the mini 6111 looked like a good candidate. Its a medium mu twin triode tube. Different pinout, so after changing a few things on the breadboard, popped the tube in the socket and fired it up.
Wow, this sounds really good without having to tweak anything. As Dano stated, it chews through batteries quickly. I then hooked it up to an adjustable power supply to try higher and lower voltages. Using a 6111 tube run at 7 VDC, I would go as far as to say, this thing sounds great! A fat tone, decent sustain, and a nice, gritty, break up when the gain is cranked. A super simple, great sounding, one tube project.
Thanks for posting this Dano.
Jered