Probably a really simple bias question

[g1]

Also, the schematic you linked is for the power supply only. I'm guessing it's also a Hiwatt based power amp, but what about the preamp?
Please post the entire schematic.

[Tom Phillips]

...Measured AC voltage across speaker load, ohms law.

Are you saying that you are using an actual speaker as the test load. If so then what is the test signal frequency that you are using? It matters because a speakers impedance varies quite a bit as the test frequency is varied.

[Chuck H]

12ax7's in any normal guitar amp circuit should provide plenty of gain to clip the power tubes with the knobs cranked and 200mV input signal. I agree with g1. I think a schematic may help.