usb dac for hi-end system

When asynchronous mode is used, Firewire and USB are identical in performance (in theory), assuming that the USB interface is well implemented. This means good design, layout and parts choices.

However, the implementation is where the differences happen, and it's due to the fact that most of these designers are not digital designers with a a lot of high-speed experience, even at the larger, older companies.

All it takes is for the designer to throw the schematic over the wall to the layout guy. This will usually ruin the design. If the designer does not do the board layout manually himself, the design will undoubtedly be compromised. He/she must be both a good circuit designer and layout designer to achieve a stellar result. There are literally thousands of critical design decisions along the way in both the circuit and board design.

Steve N.
Empirical Audio

I agree with the posters who have recommended that you consider a USB to S/PDIF converter, such as this one. You have such an amazing digital front end already. Adding a converter to it would be a very economical way of getting your feet wet with computer based audio.

definetly I agree with you on dcs gear but I just wanted to check wheter there is some other dscs or converters to be tried.
and actually ı have tried last weekend direct from mac mini via minijack to toslink adpater to dcs dac, result was really satisfying.