I am losing my ability to reason as I approach my 7th decade. Can someone help me to think please? I dug out my room heater project to clean it up a bit for the winter. I built a pair of monoblock 6C33C Push Pull Parallel OTL amps a couple decades ago, and they sound excellent. I originally built it with what I had laying around, the transformer count is high and very heavy. I would like to replace the 6 pound bias supply transformer with a small 25VA-ish toroid. Bias is -60 in relation to 0V, and -60 in relation to -150V. Can I just run 2 bridges off one transformer winding without exceeding some unknown limite? Current schematic (- a pair of output tubes) below..
Assuming the toroid still has two separate 70V windings as per the original, yes you can do that. Your bias supplies only take milliamps, so surely you only need a little transformer, not a big honking 25VA?
He needs 2 independend floating neg grid voltage supplies, one for each channel at point A/B, Plus 1 neg grid voltage at C/D. So a total of 3 independed supplies is needed.
Easiest would be 2 small (5VA?) double chamber transformers for A/B.
But you also would need 1 (quite a bit bigger one) to supply the gridvoltages at C/D AND the 260Vac needed for the 360V anodevoltage.
So, would not bring much savings in weigth.
Last edited:
Bob, unfortunally this would not work. The technical reason is that the voltage between point A/B and C/D would be shortcut by the diodes
Last edited:
OK, thank you. I figured it was something like that. I have the 360v covered, I ordered 2 of the Antek toroids recommended above.