The DC Offset would not trim to zero and 0.1mV
was as low as it would go before running out of trimpot. The pot from one
end to the other would only adjust the DC Offset by 0.7mV, which is much less
than I thought it would. My 0A2 are quite closely matched for voltage and
are within 0.3V of each other. Swapping the tubes had no effect on the DC
Offset so I might have to play with another tube to cancel that offset to zero.