Australian Amps

[paddy]

Interesting screen supply derived from secondary CT. Never seen this before.

I wonder if the diagram is wrong. I don't see how that would work.

[TUBEDUDE]

Haven't used the 6DQ6 but I recommend the 6DQ5 heartily! It's a sweep tube that is good for 15 watts singleended @ 300V into 1k6. The one electron output transformer is a good match.

[gingertube]

That half B+ screen supply is a widely used power supply schematic from that era. If you look at it closely you will note that the voltage at the CT will always be positive and the current always flows in one direction(due to the diodes). I have just finished the restoration of a 1965 Goldentone Bassmaster 60 which is a 60 Watt Amp with 6DQ6 Outputs and using that exact same power supply arrangement. Screen Supply was 220V and main B+ is 434V. Further research has shown that the 6DQ6A is rated at 25W maximum dissipation for Class AB1 Audio Power Amp applications which means it is OK for the 60W Amps and a 6DQ6B it is not strictly required although I would still recommend it.
Cheers,
Ian