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Push Pull 845 output stage questions

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Hi guys - could do with a bit of technical help here. I'm modelling a PP 845 output stage in tubecad PP calculator, shooting for 16 to 20 watts output through a 6.6K OPT and using fixed bias, running tubes at 80mA. If I start at 450v HT I seem to get everything looking nice, nice curves and low distortion and 16 watts output.

The only problem is the cathode-grid voltage pk reads up to about 50v, and the instructions in the software say this should be zero. So am I running into A2 here? I have no knowledge of A2 and how to implement it - can this be done?

If I reduce the cathode-grid voltage pk to zero the HT rises to 690v for the same 16W output. So is this back in class A again?

I'd like the lowest HT voltage possible because I'm an abject coward and also don't want to use special parts, double insulation etc.

What's going on here and what are my options? All advice very welcome, especially any free lunch suggestions of running this in A2, if that's the case!!! Like I say, shooting for 16-20W output - 25W would be better still.

Andy

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