I did it.
You can buy a music server, but you won't hear the difference if you do it right.
1. Get a cheap scope for $200 and see and measure the noise. It will pay for itself and you'll learn something.
2. You have to replace your SMPS with a very quiet one.
3. Filter every output with PP bypass capacitors. Especially the power to the hard drives, better to use a SSD.
4. Get a quality outboard D/A converter and power it by a super-regulator. D/C the DC of the USB in the cable going to it.
5. Shield the whole computer with low carbon sheet steel. In fact, shield all low level devices.
Don't let anyone tell you it can't be done.