Cambridge 840C as a DAC

WOW, am I glad I spotted this thread.

I am experimenting with Airport Express, to optical / CA840c and by balanced to my stereo. All files are Apple Lossless some recorded w/error correction ON. The 840c says the bitstream is 18bit, 44.1khz.....is That correct?

Problem is that every once in a while the stereo emits a very Glassy, edgy, fingers on chalkboard sound. It doesn't repeat if I 'rewind' and play that section of the song a 2nd time.

Any suggestions would be greatly appreciated. Apple is clueless, so far, and I have yet to hear back from Cambridge.

Magfan: I have not had that experience. I wonder about that TOSLINK cable though...

If you could give me even a HINT of theory as to how the TOSLINK could do this, I'll run out and get another!

I first thought it was 'too loud'. turning down didn't help
I though it could be poor digital copy. Error correction didn't help @confuser
I thought it could be bitrate, so I turned the computer buffer to Large.
Trying MP3 @160kb made it WORSE.

Still trying to make sense of this.

ANY more help? / Suggestions?

I doubt Cambridge can help and nobody at Apple has a clue, apparently.

I'm in the process of building a computer based system with a Mac Mini as my source. I'm using the Toslink out of the Mini to the 840C and I'm very, VERY pleased with the results.

I had every intention of investing in a USB or Firewire DAC, but I honestly can not imagine how the potential difference in SQ will justify the investment.

My system is a headless Mac Mini (2.53GHz/4GB memory) with an 80GB SSD. Music files are stored on a DROBO encoded in Aiff. I'm using Amarra Mini software (highly recommended!) and my iPod Touch with VNC, and the Remote app from iTunes to control eveything.

The Mac Mini is connected to the CA840C via a Van den Hul Optocoupler.

If anyone has experienced significant improvement moving from the 840C (DAC) to a dedicated USB or Firewire DAC, I'd love to hear your story... but my current setup beats the 840C's CD player as a source, and that's no easy feat!

Oh, one more thing... the Wadia 170i was my gateway drug. What an amazing little transport the iPod is! The Wadia is a great piece of gear!

Looks like you already have the 840C. If you are happy with it for CDs, you should be equally happy using it with a PC. I tried it in my system, and the sound from a CD and the PC was pretty much the same. I found it a little too detailed and "digital" for my liking but I know a lot of people like it. I ended up with a Musical Fidelity A3-24 DAC, which might be a good fit with your system.

For a USB to S/PDIF converter, I am currently using a M2Tech HiFace ($150) which is remarkable for the price, although it is a new unit and the drivers may not work with all players yet. I am used it with Wind 7 with J River Media Center, which is a great player. The 840C supports up to 24 bit 192 KHz input, so your USB converted should also if you expect to use high res tracts. A lot of the USB converers do not go above 48KHz, so that is something to watch for. The HiFace goes to 24/192.

Once you settle on a player and an interface you should be able to get sound comparable or better than what you get from CDs.