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Can I combine 2 output transformers?

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ELS122:
so I have 2 identical single-ended tube amp output transformers and I want to make a push-pull type amp. can I put the 2 transformers in series, use the center tap for B+ input and use a higher impedance speaker?

and yes I have posted this question before but I think the 'begginner' topic is better suited and I couldn't delete that post.

Ysjoelfir:
I tried that, but the results are.... well, not very good. which is to be expected since the magnetic coupling of the transformers is way worse than with one transformer hosting both windings.
This experiment was made quite some time back, I can't exactly recall WHAT was "not good" anymore, but my personal conclusion was, that it isn't worth the hassle, just use an apropriate PP output tranny.

andy3055:
Here is a good explanation:

"An output transformer designed for push-pull operation has a center (sic) tap. The HT is applied to the center (sic) tap and either end of the primary winding is connected to the anode of a power valve. In this way, current flows in opposite directions through the output transformer. If these currents are equal they will cancel out and this is why push-pull output transformers can be made much smaller than single ended ones with the same power rating- there is (almost) no standing current in the transformer so no air gap and less iron is required.
The valves are driven with identical but out-of-phase grid signals. When one grid goes positive, the other goes negative. When one valves conducts more, the other conducts less: one pushes, the other pulls. The output signal developed in the transformer is the difference between the two AC currents."

Courtesy of:  http://www.valvewizard.co.uk/pp.html

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