Audio Research I/50

Darn, I thought I heard something about self-biasing in a factory tour last September. If there are meters-can't recall, that would at least tell you when they need adjusting right?

No meters, I don’t believe. 

one of the weird things is that arc saying that the amp will work at it's best after 600 hours of using it.
on the other hand that average tubes life is 2000 h.
so it means that 30% percent of tubes life you don't get the best potential.
btw, the 2000 hours they are talking about is only when you playing music trough the  amp, or also when it on, but idle?
 

600 hours is talking about the amplifier break in and it is the one time event.

do you sure that after changing to a new tubes there is no an additional break in?