Krell KSA250 bias

[willcycle]

I attempted to change the bias of my version 3 KSA250 (~118 ma/device) to have the same lower level (~85 ma/device) as my version 2 amp by changing 4 resistors on the output board near the bias transistor. While the level dropped to ~105 ma/device there was some instability with the bias relay and/or input relay cycling back and forth with no input on the channel (I could not tell which relay was clicking as I only heard the sound). Looking at the input driver board of each amp a little closer (I should have done this first) revealed that the design of the version 2 does not include the 1.235V zener reference that the version 3 does. Looks like I will have to live with the higher operating temperature and power consumption.