[morzh]

Well....I thought, if no one knows the voltages, and all that worries me is currents, I might chart the currents myself.

So. The lower tweeter (in the sch) field coil feeds:

1. The field of the main speaker. It is 262V over 4360 ohm, or 60mA. The heaviest load on the line.
2. The main chassis. Easily measured by the dropout across R69, which results in 20mA.
3. The 6F6 plate current. Measured by yanking the tube. The result is about 33mA which isin line with its datasheet.
Total current is about 120mA (75V over 620 ohm) which is close to the sum of the parts.

So it seems normal that the voltage across this particular field coil is 75-80V. I should stop worrying.