iMac Sound Quality

I have an Apple Powerbook G4, which I've used to feed a Musical Fidelity Trivista DAC 21 through the optical out on an Apple Airport Express. The sound quality was better than the sound quality directly through the analog out on the Airport, but it never lived up to all the magical reviews I've read about the DAC 21. I never hooked the DAC 21 up to a CD transport to find out whether the limiting factor was the DAC or the Apple Airport Express optical out, but I'll bet it was the Airport. Recently, I purchased a Scott Nixon USB Tube DAC, and hooked it up to the USB connection on my Powerbook. I've been very pleased with the results, which are much better than my experience using the Airport/DAC 21. If your iMac is close enough to the stereo to use a USB DAC, I would recommend it. I'm using a 15' USB cable, and it works fine.

Hope you find this helpful.

Mark

Mark- Thanks for the feedback. I'm hoping the iMac's digital output connection is better than the wireless Airport Express or the SB3's digital output.

I'm not positive about this but, in general, I think you are better off when you use the USB out than a other out's.

"I'm not positive about this but, in general, I think you are better off when you use the USB out than a other out's."

Pardales- the USB output is powered by the PC's PSU and will transmit it's noise to the USB converter/DAC. The iMac's digital output is fiber, so the PC's PSU noise is isolated from the DAC.

Of course there's the issue of which output has lower jitter.

Better off with USB output for sound. First off, just because something is fiber does NOT mean it is the better choice. In this case if your goal is to isolate then yes you can use the optical connection. But...USB is a bi-directional connection, so timing errors are dealt with on the way in and on the way out. Not the case with your optical. Doesn't mean jitter is eliminated, don't know there is a connection that does that yet, but it is certainly better for sound quality.

If you want the best of both worlds, isolation and sound quality, you can simply use an Optical USB cable. One called Opticis is one that has been successfully used but people who want to isolate and use USB. Altough the PS on the Opticis has been called into question in the past, most people who have used it speak hightly of it.

I can say, from experience that I use a Kimber USB on my system from a MAC, and it is as quiet as a church mouse, and dynamic peaks come from BLACK backgrounds. So for me personally, isolation is not worth it.