Cleaning up SMPS output

[serenith]

I have a spare computer PSU that I would like to use to cleanly power a xonar essence ST card in my computer. I was wondering if it was possible to connect two rails together to form a pair of +24VDC and +10VDC lines, then filter / smooth / regulate them to a clean +12V and +5V.

My understanding of PS output smoothing is limited to the fact that it involves RC(L) circuits and a voltage drop, so please bear with me if i'm totally wrong and this is not feasible or advisable. I just want to keep this little project low-cost and since I have the PSU already, I thought it might be cheaper to use it then buying /building a better linear ps.

[discrete]

all the yellow (12V) wires go to the same pot on the PCB - they are not separate outputs - this is true even for most of the power supplies that pretend to have 2x12V rails. Same goes for the red (5V) and black (0V) wires.

And since the 0V is not isolated from mains ground, even using two power supplies will not work without some cheating...and possibly voiding your household insurance!

[nightanole]

no you can not connect 2 rails, sorry they all have the same base. You could use the 12v line and linear regulate it to 5v and be perfect. While alittle shady, you can also use the low current -12v line with the 12 line to make 24 volts, its hasto draw less then a half amp to be safe (ive never seen a -12v line that was more then 800ma).

A small project people do is use a smps to regulate to 3-4v above their voltage they are shooting for, then linear regulate down to their ideal voltage.

and if you want to go nutts:

http://www.youtube.com/watch?v=mK_rIs7uFlo