[quote name='Prime_BASS' post='1206100' date='Apr 20 2011, 05:01 PM']0 is maximum voltage and 10 is little charge.[/quote]
It is the other way round.
From the manual
[quote]Tube gain.
The tube gain control varies the high voltage supply to the power tubes. This allows a variety of tonal response characteristics from the power amp and replaces the limiter found on typical solid state power amps. At "10" the voltage is at maximum, providing a dynamic, highly responsive tone. At "0" the voltage is at minimum, offering a thick ended, more compressed tone. This tone can also be distorted, depending on volume level. In between settings are best for preventing harsh distortion when driving the power amp to its limits. The effect of this control increases from moderate to dramatic as the power amp is driven harder.[/quote]