Computer audio is a wickedly complicated subject that most people don’t ever really think about, and perhaps for good reason: there’s a distinct tendency for those who do think about it to become obsessive-compulsive about it. I mean, seriously: one day your soundcard dies, and you ask your boyfriend to be a sweetheart and look into it, and a few weeks later he’s spent $400 on cards and cables (when is an audio cable not an audio cable? When it’s an “interconnect”, a fancy technical term that means “overpriced audio cable”) and boxes and parts and pieces, and won’t STFU about “lossless audio encoding” and “bit-perfect playback” and other crazy technobabble.
Dangers aside, computer audio is pretty interesting, you have to admit. One of the most basic – and most important – bits of the chain of things that makes the ones and zeros on your hard drive (digital information) into oompa-loompas in your speakers or headphones (analog information) is somewhat obviously called a “digital to analog converter”, or DAC. You can build your own, if you’re so inclined – a new project has just been released – or, if you’re less technically inclined (soldering surface-mount components is not for everyone) – you can just buy one.
Buying a DAC has its advantages – no soldering, no frustration, no second-degree burns – but also its downsides. The biggest is that interfacing them with computers isn’t always super-simple: optical inputs and outputs are the “norm”, though there are DACs that plug right into a USB port. This is of course remarkably convenient – but you generally pay for that convenience.
You don’t have to, though. Because, as I discovered, you can buy a quite acceptable DAC for under $40. The catch? It’s not marketed as a DAC, per se. (Realistically, this means the audiophile community won’t touch it, which is good, because it keeps the prices down.)
I’m speaking of the Griffin iMic, which is marketed merely as an “USB Audio Interface”. For the most part, it’s used by Mac owners who need to connect microphones or other audio equipment to their computers (Mac laptops not having microphone or line-in connectors). But, what a lot of people forget is that it’s also a USB “line out” device – in other words, a DAC.
Now, I should state up front that I hate the iMic, because it sucks as a microphone preamplifier, which is what most people seem to use it for; because it’s hideously Mac-themed white, and because it’s more cheaply and flimsily made than a Happy Meal toy. That said, when playing around with it as a DAC, it proves surprisingly decent. This surprised me – not just because everything else about the iMic is horrible, but because the chip at the heart of the device – the Micronas UAC3556B (PDF!) – wasn’t really designed for “serious” audio use – it has a slew of really nifty-sounding features like “bass boost” and hardware equalizer capabilities that are better suited to the computer-gaming headsets where it’s usually found. Griffin, though, seem to have not implemented any of these dubious “features”, and the iMic works as a DAC very well.
If you just need a decent line-out from a computer, to interface with an amplifier or something, you can definitely do worse than the $40 iMic. I can’t guarantee how long the dumb thing will last you, but while it works, you’ll likely be very happy with it. If you’re a little more discriminating – i.e. you’re considering it specifically as a “cheap DAC” – you might be surprised by how good it sounds, and performs. It sounds good to me – very much like the Alien DAC I built last year – and while I don’t really care about audiophile crap like “bit-perfect output” or whatever, and can’t answer any questions about that kind of stuff, I did run some tests on the iMic,
which you can read right here. (The tests shown were at 16-bit, 44.1KHz, which may or may not mean anything to you; results were basically unchanged for other qualities and sampling rates.) If you’re into that kind of thing, you might be surprised at just how well this flimsy piece of plastic performs; yes, a DAC by any other name really can sound “sweet”…
(Edit, 16 October: Okay, so nevermind the tests, which were performed incorrectly. “True” measured performance is decent, but nothing to get too excited about; it still sounds good, though – and that’s what’s important, I think.)