Bridge Rectifier + Gz37

[pre65]

Hi-is there any benefit,when using a bridge rectifier,to feeding the + to both inputs of a valve rectifier.

Will this give any benefits apart from a slower HT turn on ie extra smoothing and how would (or can you not) model it in the PSU calculator.

i have seen this arrangement in a published power supply for a 211 amp which i can scan if anyone is interested.


Philip

[NickG]

There are a couple of advantages. The slow turn on you mention, and the valve removes the switching noise from the bridge, as the valve switches off before the diodes. Also, the valve doesn't see much voltage, so its also nice on the valve.

[Richard]

Hi Philip

This arrangement is also used in the old WAD 300BPP. A couple of further points are that the valve has an impedance which will drop voltage off the bridge and also work as the series leg of a filter with any following cap to lower hum.

Rich

[Les Reed]

That's quite a nice arrangement Richard, thanks for reminding us, I had forgotten what a good design the old 300B pp was. I also like the use of two chokes to split the HT for both channels. I've used a bridge of Svetlana 6D22S in my 845SE, but although giving a very ample supply they are a bit wasteful of energy and the amp gets pretty hot after about 3 hours. Might consider using a solid state bridge and GZ34's for future projects.