[rfeenstra]

The cathodes for each channel are hooked together and run through a 3.3 ohm cathode resistor.  That's where bias current is measured.  I like the idea of individual 10 ohm resistors as it would allow measuring the current in each tube rather than the combined current.  The Scott has separate bias and balance controls for each channel so setting the bias for each tube would be doable.  I like David Gillespie's bias circuit as it runs the tubes close to cutoff should a bias pot open.  If my bias pot opens, the tubes would redplate.