Can two single ended OT's be wired for push pull use?

[anson]

hey folks,

Can two single ended OT's be wired for push pull use?

I've got two single ended output transformers taken from some old TV or radio (I couldn't really tell). Originally each transformer was wired to a small power pentode (each output pentode was some variant of an el84 with a small triode housed in the same vacuum tube), and the OTs had output leads that were presumably speaker leads. I say "presumably" because I got these parts from a friend after they were taken from the original appliance housing, so I'm not 100% sure what the transformers actually powered.

The way I understand it would be that to wire them as push-pull, I would wire the secondaries in series and use those free ends for the speaker, and I would wire the primaries in series but use that junction as center tap. Is that right/wrong?
Thanks!
Anson

[kleuck]

Can't see why they could not ? I wonder though what difference(s) can make the separate iron cores.

[R.G.]

You can wire them up that way and probably get it to work, but electrically they will still act like two single-ended amplifiers running out-of-phase, not like a push-pull transformer.

The common coupling through the shared core in a push-pull transformer is important to the push-pull action. Perhaps more importantly, the common magnetic field and alternating directions of magnetization is what makes a push-pull core smaller for the same output power.

[kleuck]

At least, you can make a true class A push-pull.