Looking for a high power SMPS, anyone?

[Bricolo]

Hi all,


I'd like to make a PA poweramp for a friend, and he's concerned with the budget. The toroid for a 2*200W amp would cost too much

I was thinking about an SMPS, is it possible for something like +/-60V 8A?
If someone can post (or link to) a schematic/article/tutorial, it would be nice

And, I've never worked with such stuff, are there any special precautions to take? Compared to linear supplies.


Thanks
Alex

[Sch3mat1c]

Well, I can't offer any advice for line operated equipment (which any non-hybrid SMPS is until the transformer) but there's a real cool program that automatically computes things for you.

http://henry.fbe.fh-darmstadt.de/smps_e/

For 500W I'd recommend half or full bridge...

Tim

[Bricolo]

Thank you

and what would be a good starting point for an smps beginner?

[markp]

Originally posted by Bricolo
Thank you

and what would be a good starting point for an smps beginner?

Dangerous place to start learning about smps'! Maybe you could find an old used amp with a nice linear supply that is still in good shape.

[Bricolo]

I'll have to learn one day...

[Pjotr]

Originally posted by Bricolo
Thank you

and what would be a good starting point for an smps beginner?

Building a simple self-oscillating Roger up-converter, something that has 12V or so as input.

Under NO CIRCUMSTANCE mains related stuff. That is really only for well skilled, well experienced electronic engineers fully aware of the safety issues involved.

[Bricolo]

but a 12V input circuit will be unusefull for me

[bzdang]

Don't go there! Every new electronic design has teething problems but large smps have large fangs. When problems occur, semiconductor devices will explode and eject hot fragments at high velocity. I've watched a team of engineers develop some large smps for power amps, they are complex things with high frequency, high voltage, rfi, and many evil noise problems which can only be solved by witchcraft.
I suggest to search in surplus equipment sellers for a used smps with suitable output and a nice safe housing. Also check mains and the air for conducted noise and rfi, under load, so that you do not create a broadcasting station in the amp

[Bricolo]

How do I check for RIF in the air?

[Sch3mat1c]

You print this, throw it in the air and spot it floating down.

http://www.acronymfinder.com/af-quer...ct&Acronym=rif



But seriously, RFI can be detected with a probe... if you have a 50uA DC meter and a germanium diode you can scope things out.

Tim