Dave
You have that right.
And
The 310 has the filament as 1 turn around the center leg
So it's 1.3V/Turn on the center
The 647 (and 547) have the filaments around the outer legs
so it's 2.6V/Turn on the center
and you have to adjust as you switch back and forth to compare the two
transformers
and for me a light just went off that the 310 has more 2X the turns, so it's
capacitance would tend to be higher
John
I think 2.6V/t on the center leg equates to 1.3V/t on the outer legs,
because each outer leg conducts half of the center-leg flux.
Dave Wise
