In the continuing saga of my 6111 submini tube fetish, I tweaked this some more. After some breadboarding and measuring, it was clear that the 9v source in the previous schematic, as it relates to using the 6111, doesn't work well:
- The heaters call for 6.3vDC. At 9 volts on the previous schematic, they aren't going to last too long
- 9v was simply not providing enough boosth. So I bumped the supply up to 12vDC
To get a nice stable 6.3v heater voltage, and to add a little bit more control, I put together a power supply based on the LM317 adjustable voltage regulator. In combination with a 1Kohm pot/trimmer, I can tweak the heaters to as close to 6.3v as I want. I also added R1/C1/C2 to add a bit of noise reduction to the power supply. Note that the LM317 is going to get really hot, so slap a heat sink on it. You can get the 317 at Radio Shack, it's that common. Adjust TR1 to get 6.3v at the 'heater' connection.
Here's the schemo:

And a picture on the breadboard:

The end result with this new tweaked design is that it offers a substantial increase in boost over the 9v in/heater design, and the overdrive sounds a lot nicer.