pete321:Craig M.:
i'll try to anticipate some of them
min filter is best, optical is better then usb, unless your amp reverses phase leave it as normal, read pjpros post on getting "bit perfect" output from your p.c., don't be suprised if it isn't quite as good as your cdp, you won't hear a difference between optical cables.
I'll put a different view, Linear filter is best, SPDIF is better than USB, but I prefer Coax over optical, bit perfect is definately worth the effort of trying to get it. Finally, my lossless music rips are sounding better than a CDP (no jitter) and I wouldn't spend a fortune, but I think a decent dgital cable is worth the expense.
As soon as funds allow, spend between £150-£200 and get some Burson opamps and a few better capacitors installed and you'll turn a good DAC into something really special, not forgetting the Maplin L54BR 12v 3a PSU.
maybe your system isn't revealing the graininess in the treble with the linear filter. the min filter also has a fuller bass, which should suit the op's standmounts better.
you may prefer coax, but not many pc's have a coax output.
your lossless rips through a dacmagic sound better then a cdp? which cdp? maybe you should try some better ones.