i know what a sound card is, i just want a usb one that can go digitally so i can use bass management on my receiver, which i cannot do with the 7.1 in and i'm not going to count on a cheapo usb card to do that right if at all.
You may be overthinking what these things will do.
The audio is on the disc, or file you are playing back. It is sent natively, without conversion, from the digital audio output of a sound card to the receiver to handle. There is nothing the sound card does other than provide the proper interface for your audio playback device.
USB is a digital transport stream for data and a direct USB to digital audio converter is not a real product. Basically it must speak in a language the computer understands to transfer the audio data out of the computer, then into a system that runs the coversion from USB protocol standards to Toslink or S/PDIF standards.
Now, if you want to get the audio stream out of your computer another way, you could get an Ethernet audio adapter, which does the exact same thing that a USB one would do.
These adapters don't TOUCH the data itself, but allow the PC, which is not an audio device natively, but is a data device, to get the audio off your hard drive (or playback disc) and into another format which it can play friendly with (Toslink).
Do you think a SoundBlaster card installed inside a desktop PC does this any differently? Because it does not. Do you think spending a lot more for something which does the same thing will somehow affect the zeroes and ones? Because it won't.
You don't go USB to Toslink - it's like plugging the keys from my Honda into your car - it just doesn't work. It's not built to work that way. You gotta have the right keys match up for things to work.
