filtering switched mode PSU for SI 5066 amp supply

[jives11]

Hi,


I have a sonic impact 5066 mini amp (see under Class D discussion - subject "$30 amp" ), intending to use it to power some RS LX5 speakers connected to my sons PC,rather than the standard powered speakers for PC's.


It works and sounds pretty good using a 12v supply I found in a drawer. I'd like to power the amp off of the PC ATX PSU. You can get a card which occupies a PCI slot on the back of the PC which provides 12Vdc socket you can use to power external devices.


This basically taps a spare 12v supply from the PC switched mode., at up to 5 amps I believe.

I'd like to use this to power the SI mini amp as :

1) I don't want more wall warts

2) If I use a PSU on the PC the whole thing gets powered up/down with the PC.


Now I understand that as a by product of how the work Switched mode supplies generate a lot of noise.


Q: Is there a way of filtering out the noise ? or at least improving it ? for example cascaded ceramic caps of decreasing value i.e 0.01uf,0.001uf,0.0001uf


I know that these amps sound best when powered from Linear or battery supplies but sometimes you have to compromise.




many thanks