tube amplifier auto bias- accurate?

I wonder if Macs were the first ones to implement autobias successful in their vintage gears like the MC240s.

Ed_sawyer...Actually, you can use a scope to measure voltage if you are too lazy to go to the cabinet and dig out a voltmeter. Or, if you want to impress an audiophile.

I also know how to add on a slide rule (remember those).
And count to 35 on my fingers. (Hint...use two-place base 6).

Eldartford, one cannot add on a slide rule, only multiple and divide and other operations, but no adding (nor subtracting, obviously). The scales are logarithmic to permit multiplication by adding powers. I still have my sliderule in my desk, for nostalgia!

Bob P.

"I wonder if Macs were the first ones to implement autobias successful in their vintage gears like the MC240s."

Doubtful. bias as a concept is as old as tubes, e.g. early part of the 1900s, 1910-1920 is when most basic concepts and methodologies were developed. Not much has changed since then. Things rediscovered, e.g. Parafeed, etc.

-Ed

Bob P. as the saying goes, "If you can't dazzle them with brains, baffle them with bull$#!^"