Best Digital Input from PC to DAC

I'm currently using a Kimber USB cable from my PC to my DAC to play FLAC files ripped from my cd collection to a hard drive. Although the results are quite good I'm interested in other Goners experience with USB or alternate input choices using a lap top computer for manipulating music streams. I've found that FUBAR and the free ASIO drivers render the best results in play back.
The Empirical Audio Freeway 2 takes usb out of the computer and brings it to the Dac of your choice. There are other ( cheaper) alternatives, but you are making some great choices with Kimber, FLAC, etc. , so I think you are really close to great sound. Have fun.
Some USB converters were compared here:

If you are using XP on a PC, then I would recommend unmapping the device if possible and using Foobar 0.8.3

Steve N.
Empirical Audio
Agreed, if money isn't a concern get Steve to hook you up with one of his options and skip all the experimenting. If value is a concern there are lots of cheaper alternatives to keep you busy.
What DAC are you using? Many USB enabled DACs aren't doing it right and will give you less than the best results.
If you want to stick to the simple computer/DAC solution, I have liked what I've heard from DACs with an asynchronous capability. This allows the clock in the DAC to control the data stream from the computer. Wavelength USB DAC is a good example of this approach.

If cost is no objective, then Emperical Audio components seem to me to be the best technical execution of computer/DAC my opinion. It often means adding and/or modifying components, but I2S blows away most other connections in terms of minimizing errors.

An alternate path (which I prefer) are the "single device" solutions like the Slim Devices Transport that send a raw data file to the device where it is decoded, converted to digital stream and run through D/A conversion on one circuit board. This represents the fewest potential places for problems in the signal path. If you look at the ModWright Transporter, you are pretty much matching the best source components out there for under $4,000

More choices are on the way in the coming months, but you are on good footing right now and aren't missing anything earth shattering.

For the record, I run FLAC files through WinAmp with the ASIO plug-in myself (I like the WinAmp better than Foobar - just a personal preference). I also run a modified Sonos network to my DAC for non-critical listening. Lastly, I have a Fubar 3 headphone amp/USB DAC with Sennheiser headphones at work - great sound for under $300.

Hope you are having as much fun as I am!
My setup involves a Vista desktop or XP laptop to firewire Focusrite Saffire LE, Paradisea+ NOS DAC with Bendix tube output stage, the non-USB version, a NuForce processor, Gemstone amp, and Selah Audio 5.1 speaker setup. Using FLAC and either Foobar or Media Monkey. Speaker cables are twelve guage wire and homemade, silver series interconnects, stock firewire cable. Various configurations are possible. I've never really got around to a proper home setup since the basement is still not finished.
Look into firewire. Much better than USB.
A low cost option might be iTunes feeding an Apple Express with TOSLINK output connected to a Benchmark DAC1. The DAC1 is not the latest and greatest but has a long reputation at being good at removing bad jitter. Another option would be to get the USB DAC1 version (which is newer and may not be easy to find second hand - also being newer I am not sure if it has an established good track record). An alternative would be the Lavry DA10 which claims to have good jitter rejection (although I have no experience with that one)
Cerrot - you have not heard every USB converter or DAC, so please reserve judgement. I will put my USB converter up against your Firewire anytime. I'm confident that I would win the shootout.

I realize that you believe your system sounds great etc., but trust me, there are lots of systems out there are are superior. Everyone is at a different level here. It is all relative.

Steve N.
Empirical Audio
Be careful of those "low-jitter" claims. Even Stereophile made measurements on Squeezebox and Sonos - they were both low according to them (under 500psec), and the Sonos was only slightly worse, and yet the jitter is obvious on both and a LOT worse on the Sonos.

Steve N.

Thanks for the grate feedback.
I'm using the Emm Labs DAC 2 which has numerous input choices, 1 of which is USB. I find the results to vary significantly from my stand alone single box player. Music files sound Slightly distorted and compressed. I know this DAC is capable of very good audio output.
If you are using XP, I would recommend unmapping the device. This will make the USB interface sound a bit better. USB interface quality varies a lot from one product to another, so it may stil not be better than the S/PDIF input. Here is how to unmap:

Go to Control Panel - System Hardware - Device Manager - Sound Video and Game Controllers – Empirical 1.1 - Right-Click and select Properties - Audio Devices – Empirical 1.1 - Properties - Set "Do not use audio features" and set "Do not map through this Device"

You will need to reboot and then if you change it back to mapped, then you must re-boot.

Steve N.
Empirical Audio