|5th June 2009, 04:37 PM||#91|
Join Date: Dec 2003
Location: Sierra Foothills - California
For a class AB amplifier you are correct. But the A40 is a class A amplifier. So the object is to set the bias high enough to allow the amplifier to remain in class A for as wide a range of load conditions as possible and low enough to prevent it from thermally self destructing.
Regarding the efficiency? That's a personal decision. My choice would be to run class A and turn the fire down one bar.
I have built two A40's although it was long ago. Both came up without a hitch and ran hot and trouble free for years.
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