Best soundcard if have outboard DAC


Looking to use a PC as a transport. Will have an outboard DAC feeding a preamp. I want the soundcard to feed the DAC with a digital signal. I don't want the PC/soundcard doing any processing, only sending the untainted digital signal to the DAC. Sound is important, not cost. What is the best soundcard for this? Also, what is best: AES/toslink/USB?
bigamp
How do you guys bypass the Kmixer in Windows?? I use both my on board Nvidia sound card (optical out) as well as a Maudio 2496 (coax).

Unless I play DD or DTS, I am always able to change the volume with Windows meaning that the signal gets converted somehow. I use digital out but since Windows acts like a preamp I'm really not getting any benefit from using a external dac.

I'm using foobar 2k for music playback.

Any help would be greatly appreciated.

thanks
thanks, do I need some extra software to enable these two or are they soundcard options. I tried enabling ASIO on my M Audio soundcard but the Windows volume still worked.

Where do I enable Kernel streaming, is it from foobar? I really lack computer literacy when it comes to PC music but I hate having to change cds every 5 mins so a jukebox is the only way to go.