Options for 300mA tube rectifiers

[andyjevans]

It's always tricky to find tube rectifiers capable of 300mA at 350v to 400v for things like Push Pull amps.

I've had good results so far with two 6BY5, and about to try two 5R4GY. I've previously used damper diodes like 6DT4, but a pair are problematic around 250ma and over.

What are your solutions and experiences?

Andy

 

[Eli Duttman]

A GZ37 is good for 350 mA., into a choke I/P filter. Only 275 mA. are available from a GZ37, when cap. I/P filtration is employed.

 

[Vinylsavor]

Hi Andy,

many choices among the TV dampers. Since each diode will only conduct half the time, the current drawn from a pair or a bridge can be twice the DC current capability of a single diode. I'd leave some margin however. A 6AU4 might just be enough.

300mA will be absolutely no problem for 6CJ3, EY500 or 6CG3:

VinylSavor: Tube of the Month: The 6CG3

Best regards

Thomas

 

[roline]

I use solid state bridges with a 6CG3 as a "pass device" in the B+ to delay conduction to the rest of the amp to match the tubes as they warm up. First application was on the KEG-EAR ST70 clone application, worked great so I'm using it in all other power supplies.

 

[radiostar]

PY500A is also very good for excellent price, if you can afford new transformer for heating ...

 

[Palustris]

The 5V3 and 5V3A should handle the current without a problem.

 

[Eli Duttman]

A 6AU4 might just be enough.

I think a pair of 6AU4GTAs will be quite adequate in a 300 mA. PSU. A look at the data sheet shows a 190 mA. DC rating as a (sic) 1/2 wave rectifier. Damper diodes are built to take repeated large pulse draws. A "yank" 50 or 60 times a second rates to be a "piece of cake". The only thing to watch out for is an excessive turn on surge working into a cap. I/P filter. Don't be aggressive in sizing the 1st filter cap. and (of course) use a CLC filter.