01-05-2014, 09:12 PM
One final question regarding my 37-650:
I noticed that the two 6F6 output tubes are wired in what I consider a strange way. They don't have a separate phase splitter, they seem to be using one of the 6F6's screen grid to generate the 180 degree out of phase drive to the other 6F6's grid.
They use a 3500 ohm dropping resistor to the first 6F6's screen and then
AC couple that screen to the grid of the second 6F6. The second 6F6's screen is tied directly to the screen voltage line.
Kind of a clever trick I guess, I just never have seen this in any book
before, even the books from the 30's and 40's.
Does anyone have any info on this technique?
Certainly saves either an extra tube or another audio transformer...
Thanks,
Herb S.
Ithaca NY
I noticed that the two 6F6 output tubes are wired in what I consider a strange way. They don't have a separate phase splitter, they seem to be using one of the 6F6's screen grid to generate the 180 degree out of phase drive to the other 6F6's grid.
They use a 3500 ohm dropping resistor to the first 6F6's screen and then
AC couple that screen to the grid of the second 6F6. The second 6F6's screen is tied directly to the screen voltage line.
Kind of a clever trick I guess, I just never have seen this in any book
before, even the books from the 30's and 40's.
Does anyone have any info on this technique?
Certainly saves either an extra tube or another audio transformer...
Thanks,
Herb S.
Ithaca NY
