The 6GM8 is the same size as a 12AX7. In the Nano they use miniature tubes and a have a switch mode power supply to get the plate voltage of approx 250 volts. The smaller a tube the shorter its lifetime also the tubes in the Nano are soldered in so? If you want a low wattage amp I would build a Firefly for a lot less money. Ted Weber has the transformers cheep and the board is 20 bucks.


You could also consider adding a variable voltage regulator to the Crate V5 if you are modifying it for a low volume overdriven sound in that mode the power tube should last a long time.