Soz Psu

[akira]

Hi all,

I m building a SOZ PSU. I m facing a kind a dilema (not that serious).

I have 800W/2*30V toroid transformers. Another part I already have is a bunch of 47000 uF/50V caps. If I go for a Pi filter, I'll end up with 43V rail which a bit to close (I guess) to the max rating of my caps.

I was therfore thinking to chokes. What about inductors (2mH) right after the rectifier. I d have 0.9*30 instead of the 1.4*30. It would lower my voltage.

Some questions now :
1. If I wind my own chokes, what diameter should I use ? #10 ? #12 ?
2. Is the efficency of the inductor regulation much lower when I put it after the rectifier instead of putting it in a Pi filter like described in Mr Pass Zen amps ?


Thanks for your help and thx to Mr Pass for shearing your knowledge with us.

Akira

[BobEllis]

your 50 V caps will be quite happy in a pi filter, don't be afraid to use them that way.

[Magura]

The "official" solution is to use chokes both after the rectifiers and in between the caps.

# 12 will allow 6ooW for each secondary for a 2mH inductor.


Magura

Edit:

I though dont see the problem in 43 V rails and 5o V caps.

[akira]

Interresting, thx for the answer.

But this answers give me another question. Since I don t want to run a 30W SOZ (too expensive electricity bill) I could maybe use 7 volts to build the active supply regulation of Zen part 3.

This would give me a nice 35V rail for a 20W SOZ. The total dissipation of the amp stage would be around 500W instead of the 750W of a 30W SOZ (Pi capacitors resistors filter).

How much would be the power eaten by the regulated PSU ?

Do you think this would be a good solution ?

[BobEllis]

500W dissipation on +/- 35 Volts means just over 7 amps bias. 7 volts dropped on each rail x 7+ amps means around 100 W in the two regulators.

Not much of an energy saving, but some.

[moe29]

Just remember with a regulated PSU you have even MORE heat to dissipate!

...maybe wire your transformers for half the voltage.