Chimera labs monoblock ace by Dennis Boyle, anyone have them ?

Hi ! audiogoner ! i have a pairs of chimera labs ace prototype by Dennis Boyle which i really liked them , currently i have 6l6 power tube and the previous owner said that i can used el34 or kt66 for them but i never try them as i don't know how to bias them, i saw there a knob on the back of each with 5 position adjustment i got no idea what that was beside the volume control on the front , so if you have them please give me some info that will be awsome ! thank and have a great day