Modding a ATX psu for usage with class d amps

[chriscam]

Hi all,

I'm investigating whether it's possible to modify an ATX psu for usage with a class D amp. I'm aware of the fact that there are people here that have tried it before but I could not find any reports of a succesfull result.

My reason for giving it another try is because these ATX psu are incredible cheap when compared to readily audio smps modules.

I'm keeping an online version of my findings right here and I was hoping some of you smps experts over here could give some feedback.

Greetings from a cold & rainy amsterdam

[jackinnj]

One of the things you will have to do is make sure the output filter inductors are sufficiently sized for low current. There was a great ATX mod article in QEX (ham radio mag) a few months back -- all the info you need to mod the transformer and cut out the extraneous circuitry -- I believe that the designer made it stable over a range of 100 milliamps to 20 amps. Email me directly if you'd like a PDF.

[N-Channel]

I just went to the ARRL's website and couldn't find anything in QEX. Please please please post a link to the article, as I have a pile of AT & ATX boxes laying around, just waiting to be used.

'73,

de N8XO

[jackinnj]

it was the November-December issue of QEX -

[chriscam]

not sure if were talking about the same article, this one by DL2YEO even has a pcb layout

• german
• english

[N-Channel]

Thanks a bunch!

I will look it up ASAP!

[jackinnj]

the only thing which I have been cautioned about is the potential for changing the transformer characteristics by cooking it in an oven to soften the windings -- the good thing about the QEX article and using an existing board is that you maintain the barriers between the house mains and the secondary side of the supply.

QEX should be in the University of Detroit library -- as I hear they do some engineering around those parts.


73's

[N-Channel]

No PDF available from their website. I can see where/when the article was printed, but I can't get a printout of it. Can you post one?

If you know anything about the greater Detroit area, then you know that I would like to stay above 8-Mile Rd. (yes, THAT 8-Mile!) if at all possible. High crime in the city, plus a long drive. THX Much!

[jackinnj]

send me an email and I will send you a PDF -- It's about 1.4 megs

[chriscam]

Having canibalized over a dozen old atx supplies the used core appears to be the same all the time. So I searched google for a core manufacturer and bumped into Falco. Using their very nice SMPSCoreSelGuide I learned that the core is named ETD. Doing a search on ETD got me here, a german site with a full fledged core design wizzard. Very cool indeed huh.

for more info click here