Power supply for a rane RPM 26v

KOA

Member
2006-04-10 1:20 am
seattle
Here is a link to the actual supply.
http://www.rane.com/pdf/old/rs3dat.pdf
Links to regulators.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=LM7912CT-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=497-3448-5-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=LT1083CP-5-ND
Preface: I am an electronics noob

It is a 12v 800ma, -12v 800ma, and a 5v 4000ma. I can buy one for about $150. but i think i could make a better supply thats regulated. I am not sure if theirs is or not. The data sheet for the power supply says the 5v should be within (i assume +-) 0.1v. Anyway... i found some voltage regulators on digikey that will do 1.5 amps for the -12 and 12. do you think that will be sufficient? I could not find a larger current device for the -12 on digikey.

Transformer selection: should I got a torroidal that has dual tapped 12's and a 5 additionally with individual rectifier bridges? Rectified those voltages should come up to a suitable dc voltage for the regulators(about 16v for the +-12 and 7.5v for the +5 ??). Or should I get a single output transformer because all my regulators can handle up to 30v on the input? Single rectifier bridge tapped at different points for the + and - 12(is this possible??). And the 5v regulator on the same line as the +12??? Would I only need to assure an appropriate VA rating so the 5v regulator would not affect the performance of the 12v regulator? Or would i need to compensate voltage wise???

I guess after that is figured out I could probably use some advise on filter cap sizes and type. I was looking at the Panasonic FM series for the main supply caps(electrolytic). They recommend tantalum caps on the output(and input if located some distance from the main supply caps) of the regulator. Any advice would be greatly appreciated. Thanks
 
Well if you only need 800ma at 12v then the LM7812/7912 regulators will work fine but you might need to heatsink them.....There is also a way to get more current out of your regulators useing a pass transistor...Look at the datasheets as they should have examples how to do this.....

You should be able to build this PSU yourself for much cheaper than $150 ,It shouldn"t cost more than $20 in Parts.....