Patrick Turner wrote

Ian Iveson wrote:

Bret Ludwig wrote

Partridge figured out that tolerance of up to 10% DC imbalance was a
necessity for the highest level of OPT performance and he was right.

10% of what?

In Tremain's Audio Encyclopedia there is a graph for IMD vs DC imbalance
between primary halves.
So where you have 45mA in one tube, and 55mA in the other, then you have a
20% imbalance,
since 10mA more Ia flows in one of the tubes compared to the other.

snip...

Thanks. Could have meant anything.

cheers, Ian