Question about stacked pawer supplies

[sesquialtera]

Hi have built Gary Pimm's 47 PP amp to revision 9 and want to rebuild the power supply to his stacked supply in rev. 10. I'm having trouble wrapping my head around how the ground reference works. Gary uses non-center-tapped transformers with Graetz bridge rectifiers. My transformer is a center tapped 375 -0 -375. Would there be any issue with using the center tap and full wave rectifier?

Thanks for any guidance you can give.

[kmtang]

No problem at all. I think it is even better.


Johnny

[kevinkr]

Originally Posted by kmtang

No problem at all. I think it is even better.


Johnny

Seconded..

[sesquialtera]

Great! Thanks for your help.

[leadbelly]

Maybe I'm the one who doesn't understand, but if you mean can you use just a fullwave tube rectifier and a center tapped transformer and build that PS, the answer is no. You need some technique to derive 2 rails, so at the very least you need to use a Graetz bridge with your fullwave rectifier and center tap.

[sesquialtera]

Hmmm.. I thought that for a Graetz bridge (like a fullwave ss rectifier) one would normally not connect the CT, but I guess being able to derive the 2 rails is the crux of my confusion.

If I did the Graetz bridge with FW rectifier and CT, wouldn't my output voltage be way too high?

Thanks!

[leadbelly]

Originally Posted by sesquialtera

If I did the Graetz bridge with FW rectifier and CT, wouldn't my output voltage be way too high?

If you look at Pete's supply that you are trying to build, the output is 442V + 35V = 477V across both rails. Of course, your bridge stage actually needs to be higher than that since you need some voltage headroom for what is burned off as heat in the CCS and resistors.

You can't just use a FW tube rectifier, look at the rest of the circuit, it needs 2 rails to work.

[DougL]

sesquialtera,

If you have something that you think should work, post the schematic.

Doug

[sesquialtera]

Thanks for the explanation, leadbelly. The concepts are starting to sink in. I'll go with Graetz bridge and no CT connected as per Gary's schematic.

[leadbelly]

Originally Posted by sesquialtera

Thanks for the explanation, leadbelly. The concepts are starting to sink in. I'll go with Graetz bridge and no CT connected as per Gary's schematic.

That of course will work, but if you want to go ahead and use your CT to avoid extra components, that is still a worthwhile goal, as others have already said. Maybe you should tell us more about what you were intending to do? You have this power trans that you mentioned. Do you have a tube rectifier on hand? Were you planning to use solid state rectifiers? Some more info would be a great help.