A few weeks ago, during a spell of unusually dry winter weather, I went to unplug a pair of Grado SR-80 headphones from my iMac. A spark of static electricity leapt from my fingers, I heard a brief crackling sound, and then… [silence]. From that moment forward, the headphone/speaker jack on the back of the Mac has refused to work, and only “Internal Speakers” showed up in the System Preferences Sound panel. My trusty work Mac had gone mute.
My only options were either to send the Mac in for repair or switch to USB audio output. I couldn’t afford to be without the Mac, and I was interested in hearing what kind of audio upgrade I’d get by bypassing the Mac’s internal Digital Audio Converter (DAC), so I hit up an audiophile friend for recommendations. Hit the jackpot when he suggested the NuForce μDAC (aka microDAC) – a handsome $99 outboard DAC smaller than a pack of smokes.
The unit arrived a few days later and I was blown away from the moment I plugged it in and enabled it in the Sound prefs Output panel. Digital audio has never sounded better on a computer I’ve owned. But since the original analog jack was fried, I had no way to directly compare the quality of the Mac’s native DAC with the new outboard. Today I sat down at someone else’s work Mac and did some A/B testing.
For the test, I chose two recordings:
- Sonny Rollins: “I’m an Old Cowhand” (from Way Out West)
- Beatles: “Because” (from Abbey Road 2009 Stereo Remaster)
(I chose these two because A) I love them and B) I had them on hand at 256kbps AAC, for best possible resolution).
Full disclosure: I appreciate great-sounding audio, but I’m far from a hardcore audiophile. For a balls-out audio tweak’s perspective on the μDAC, see HeadphoneAddict’s review at head-fi.org.
Just a few minutes into Cowhand, I noticed something I’d never heard before: The sound of the cork linings of the valves of Rollins’ saxophone tapping away as he played. It was subtle, but it had been there in the recording all along – I had just never noticed it. And that’s exactly the point – the differences are subtle, and you may not notice all of them unless you’re listening for them, but they’re present. And that subtlety adds up to an overall experience that’s simply more realistic, more nuanced than what you get with the cheaper DAC built into consumer PCs. It’s all about presence.
Likewise, I found the harmonies in Because fuller, richer, more bodied than they sounded through the Mac’s native DAC. The French horns far more alive and breathy, the harpsichord more twangy. Virtually everything about these two tracks sounded more engaging.
Another thing I noticed: Usually, near the end of a long day writing code, I feel the need to take the headphones off and rest my ears. I didn’t have that sensation today. I can’t say for sure, but I suspect that more natural sound is less fatiguing to the ears (and the brain’s processor).
One caveat, and this is true for any USB audio system attached to a computer: Because there’s no longer an analog sound channel for the computer to manipulate, you’ll lose the ability to control volume or to mute from the Mac’s keyboard. That habit has been ingrained for so many years I don’t even think about it, so retraining myself to adjust audio from the μDAC’s volume knob will take some getting used to. However, you can still use the volume control in iTunes itself, and it may be possible to re-map the keyboard’s audio control keys to tweak iTunes’ internal volume directly.
In any case, the NuForce μDAC is one of the best c-notes I’ve dropped on audio gear over the years. Recommended even if you haven’t fried your analog port.
Scenario: Music collection on an iMac in the office on one end of the house, pumping music over Airport Express to stereo in the living room on the other. Need to be able to remotely navigate collection and control playback from a laptop in the living room.
Alternative 2: Third-party software. There are a few shareware packages available in this niche, but the only one I found that worked reliably was Jonathan Beebe’s open source 
Podcasting changed my life. 
