Empirical Audio offers these extremely high quality items:

from Empirical Audio

USB Off-Ramp Turbo 2 and USB Freeway 2

These are USB to S/PDIF coaxial converters which allow you to connect your computer
to your high-fidelity audio system and play music stored on your hard-disks. These
converters do not compromise sound quality. In fact, the sound quality is generally
superior to a CD player or even an expensive Transport and outboard DAC. What is
required in order to use these converters is a Digital to Analog Converter or "DAC".
The Converter connects between your computer and your DAC. A USB cable connects
from your computer to the converter and then the converter plugs into your DAC.
Your DAC then generates analog left and right channels to drive your audio system.
The quality of the DAC is critical if you want high-quality playback. Here are some
features in common with the two USB converters that we offer:

* USB to S/PDIF Coaxial converters
* Custom circuit-board designs - not a mod
* All have lower jitter than any stock or even modded Transport
* AES/EBU versions also available
* Standard with a short S/PDIF coaxial cable permanently attached with strain-relief
* Each comes with licensed copy of SRC, the best 24/96 upsampler on the market
* Each comes with an 8 foot USB cable
* All will pass 16/44.1kHz, 24/96kHz, MP3 and iTunes unmodified files
* AC3 support is available using the M-Audio driver
* Works wonderfully with both PC and MAC

Our USB converter products use circuit boards of our own design which are hand
assembled using silver-loaded solder for best sound quality. We use circuit topologies
parts selection and board stackup configurations that result in the lowest noise signals
and the cleanest power of any high-end manufacturer. Even boards designed by large
companies do not use these techniques because they do not lend themselves to
automated assembly or low cost. We consider cost no object. Only performance matters.
We take extreme care in every board design to optimize every aspect, including: power
delivery, signal integrity, speed, electrical noise, isolation, parts selection, ESD and
transmission-line effects. It is this care and design knowledge that enables our designs
to be superior performers.

Our USB converters will outperform even the best Transports you can buy, particularly
with 24/96kHz on a PC or iTunes with a MAC. No other cables required, just a PC with a
USB 1.1 or 2.0 interface and a DAC with a coaxial S/PDIF input. It is recommended that
you dedicate a computer or laptop to the task, particularly when using SRC upsampler.

Here is a picture of the Empirical Offramp Turbo 2 from T.H.E. Show. The USB Off-Ramp Turbo 2 is $990 plus shipping.

Here is the link to the unit on the EA site.

Let me think a little about another option for you. If you come across one sooner, let me know.

If this was that simple I am guessing there wold be many of them available for $10 all over the Internet. Not positive, just my guess. Plus Empirical has created a true audiophile quality solution.

I did find this very sketchy looking device online here. It connects via Toslink for digital audio and 3.5mm for analog audio output. Highly NOT recommended device :-)

Well, because Empirical referred us to M-Audio for drivers, I figured they might be a good source. Besides, M-Audio is an Avid company, the creators of ProTools, digital video editing, etc. They know their way around digital pretty well. I'm left wondering if I'm looking for something TOO simple. Everything seems to contain a dac, multiple processing functions - basically pro and semi-pro recording tools, interfaces for computer-based digital recording of analog instruments. If you get far enough up the food chain they do have some products with digital pass-through that would allow you to take Firewire in and send coax out but I"d be putting a multi-channel mixing board on my desk to accomplish that!

I'll keep looking. I know there's something out there...

Tim

Not up to 10.5 myself. I'm running 10.4.11 on an iBook G4. I found the device. M-Audio does make something, I was just asking the wrong question. Even this simple little device has stuff in there I have no use for, including, evidently a cheap 24/96khz dac and an op amp (there's a headphone out), but it allows digital pass-through from USB to optical. That will get the job done. $79.99 at Guitar Center.

Tim