turn of your monitor then

47uf for a audio high-freq noice filter is too high value...

normally, 1uf or 2.2uh as much 4.7uf...

But if you do it, it will depend of the impedance output of the circuit...

This filter will kill the high freq... it is as a TONE fixed control like AM radios.

The problem of the digital noice on the sound.. is because to a bad design of the mother and power supply unit....

You can found the same problem in all SOUND BLASTER card on PC....

So, the problem is no too simply of solve.

You can do 1 things.. without circuit modification...

on the STEREO you can put down the high freq of the equalizer.

Other thing you can is turn down a bit the stereo volumen and turn at the MAX the MSX volume... so the relation signal/noice is more separated and you can listen better sound.

Other thing is more complicated... it req. change the power supply for a switched power supply like PC for get a more quiet power voltage... but, some time it not work...

I got arm a circuit from the 70' than solve the problem, is a volt regulator with noice suppresion on power supply for allow a quiet sound... is special for mixers with high impedance input... but need a lot of old electronic things and is hard to calibrated.

Quote:

47uf for a audio high-freq noice filter is too high value...

I don't really know about the values for the caps, but the Turbo-R suffers more from ground-noise than high-frequency noise...