I am working on a Phico model 38-3 run 121.
The radio developed a short and really destroyed
a lot of stuff, including the output tranformer.
The radio has resistance and capacitance coupling
(NO interstage transformer)The output is a pair of 6F6's
I couldn't find an original Philco transformer
part number 32-7754. I did find a transformer from
a pair of 6V6's in push-pull. As I understand and
researched the plate resistance and impedence are very close match.
The Philco schematic shows the original transformer
as having an offset resistance mesurement from the center
tap of the primary. 310 ohms (DC) one way and 350 the other.
The transformer from the push-pull 6V6's is also "offset"
more dc ohmage resistance one way than the other.
Questions are...
1. Will it work?
2. How do I know which way to hook up the primary.
3. Why is it done this way?
4. Would I have been better to use a "universal" type
of transformer?
Interesting post just a couple of days ago from Ron Grassl
on his Gilfillan, very similar questions...
This is a great group! Thanks for always being there!
Tony
Use the transformer made for 6V6's. The output impedance ratings of 6F6 and 6V6 is similar.
The readings you found are DC resistance rather than impedance. Each side of center tap has the same number of turns. The winding closest to the core will have the least amount of wire and lowest resistance.
It doesn't matter which output tube plate is connected which side.
Norm
: I am working on a Phico model 38-3 run 121.
: The radio developed a short and really destroyed
: a lot of stuff, including the output tranformer.
: The radio has resistance and capacitance coupling
: (NO interstage transformer)The output is a pair of 6F6's
: I couldn't find an original Philco transformer
: part number 32-7754. I did find a transformer from
: a pair of 6V6's in push-pull. As I understand and
: researched the plate resistance and impedence are very close match.
: The Philco schematic shows the original transformer
: as having an offset resistance mesurement from the center
: tap of the primary. 310 ohms (DC) one way and 350 the other.
:
: The transformer from the push-pull 6V6's is also "offset"
: more dc ohmage resistance one way than the other.
: Questions are...
: 1. Will it work?
: 2. How do I know which way to hook up the primary.
: 3. Why is it done this way?
: 4. Would I have been better to use a "universal" type
: of transformer?
: Interesting post just a couple of days ago from Ron Grassl
: on his Gilfillan, very similar questions...
: This is a great group! Thanks for always being there!
: Tony
: The radio has resistance and capacitance coupling
: (NO interstage transformer)The output is a pair of 6F6's
: I couldn't find an original Philco transformer
: part number 32-7754. I did find a transformer from
: a pair of 6V6's in push-pull. As I understand and
: researched the plate resistance and impedence are very close match.
: The Philco schematic shows the original transformer
: as having an offset resistance mesurement from the center
: tap of the primary. 310 ohms (DC) one way and 350 the other.
:
: The transformer from the push-pull 6V6's is also "offset"
: more dc ohmage resistance one way than the other.
: Questions are...
: 1. Will it work?
: 2. How do I know which way to hook up the primary.
: 3. Why is it done this way?
: 4. Would I have been better to use a "universal" type
: of transformer?
: Interesting post just a couple of days ago from Ron Grassl
: on his Gilfillan, very similar questions...
: This is a great group! Thanks for always being there!
: Tony