Setting bias current using the Luxman service manual procedure for this power amp is a pain - removing fuses, and using an ammeter to set a bias current of 70 mA, measured at the power rails.
It seems much easier to just measure the voltage across the 0.22 ohm emitter resisters of the output drivers, and work out the total output stage bias from that and make sure its balanced across both channels. The difference is the factory method would include the bias current into the pre-drivers etc, not just the output stage drivers.
What percentage of this total bias current would typically be consumed by the output stage? I set it for 60 mA at the output drivers, assuming approx 10 mA of the total of 70 mA would go through the pre-stages. Fair assumption?
It seems much easier to just measure the voltage across the 0.22 ohm emitter resisters of the output drivers, and work out the total output stage bias from that and make sure its balanced across both channels. The difference is the factory method would include the bias current into the pre-drivers etc, not just the output stage drivers.
What percentage of this total bias current would typically be consumed by the output stage? I set it for 60 mA at the output drivers, assuming approx 10 mA of the total of 70 mA would go through the pre-stages. Fair assumption?