Tube DIY Asylum

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Fixed Bias can be done in so many ways

Posted by Naz on May 29, 2012 at 01:09:39:
I use PSE because I need the power but notwithstanding, properly implemented, to me it sounds better because you can halve the primary impedance of the OP tranny. I also use DC coupling almost exclusively in SETs to give me the extra overhead and less aggressive overload characteristics.

The fixed bias I use is not the normal simple bias supply connected to the grid with a high value R. I use damper diode tube rectification and small C->LC filtering to feed my driver stage(s) and the driver sets the bias voltage for the OP tube. Definitely no loss of highs here, in fact extended but smooth highs with lots of air is a must for me!

Cheers,
Naz