Tube DIY Asylum

RE: PP Class A OPT Loading

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This Post Has Been Edited by the Author

In Reply to: RE: PP Class A OPT Loading posted by TimFox on March 20, 2012 at 10:37:12

When I first studied the treatment of push-pull tubes in the standard texts, including the Radiotron book, I found the following to be easier to understand. (Ignoring inductance and other reactive considerations for simplicity.)
...
4. As the tubes swing, the total amp-turns in all three windings, carefully added together, equals zero at all times
...
5.
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Thanks Tim!
+1
This is the main assumption/simplification that allows simple analysis of unequal tube currents and is how my crossover analysis spreadsheet model works.
It also shows that you can't make the crossover bump go away by increasing the bias, short of class A operation...
And it shows that operating the 2 tubes in less linear parts of their curves is still class A; i.e. switching off, or staying at bias level for part of the cycle, is the critical difference.

Edits: 03/20/12

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