A reader wrote me recently asking my about DACs; digital-analog converters. This relatively new element in the hi-fi audio chain converts the digital stream of audio from your computer, or other digital source, into analog music that your amplifier then amplifies before sending it to speakers. (DAC chips aren’t new, but DACs as standalone devices have only become common in the past five years or so.)
Do you need a DAC? What does it do?
DACs are present in many devices. You’ve got one in your computer (it’s one or two chips on the sound card), in your smartphone, your iPod, or any other device that plays music. If you have an AV receiver, that has a DAC, as do optical disc players (CD, DVD and Blu-Ray). In short, anything that needs to convert digital audio to analog has a DAC.
A DAC, in its basic form, is merely a chip. Some sound cards, and most off-board DACs, contain two of them, or for each of the stereo channels. Some AV amps may contain one per channel; so if your amp can play 7.1 audio, it might have eight DAC chips. The term DAC also applies to a standalone device, which is essentially a housing for one or more DAC chips, and the necessary circuitry to connect the device to both input and output.
All standalone DACs have digital inputs and analog outputs. Some will have just have USB inputs and others will also have Toslink (optical audio); some will have standard RCA jack outputs, while others will also have XLR outputs. So if you do choose an external DAC, you need to make sure it has the connectors you want to use.
But if your computer already has a DAC, then why would you add an external DAC? Many computers scrimp on the quality of the DAC chips they use. The smaller the computer, the less likely it is to have a good DAC. In other words, a desktop computer may have a better DAC than a laptop. So, if your computer – or other playback device – is cheap, then an external DAC might make a difference.
DACs can run from less than $100 to many thousands, but, according to many people who have listened to different DACs, they generally sound the same. In fact, they should sound the same; DACs shouldn’t alter the sound of the audio they convert, they should only convert it correctly. So the analog conversion of a ripped CD should sound like that CD; the sound shouldn’t be altered by the DAC.
So, do you need a DAC? I happen to have one, a Cambridge Audio DACMagic, that I got for review about five years ago. (The current model is the DACMagic Plus (Amazon.com, Amazon UK), which is a bit more recent.) I found that it markedly improved the sound of the music coming from the Mac mini, which was the computer I was using at the time.
However, now that I have a retina iMac, I have a feeling that this better, more expensive computer is likely to have a better internal DAC. I still use the DACMagic, but if I took it out of my stereo chain, I probably wouldn’t notice as much difference. I’ve done some very simple tests, removing the DAC from the audio chain, and using an analog output from the iMac, and not noticed any real difference, but I didn’t spend much time testing it, and it’s very hard to do a blind test; I’d really need two iMacs to test it correctly.
(Apple uses the Cirrus Logic 4206BCNZ in the retina iMac ; this is very similar to what was in the Mac mini: Cirrus Logic 4206ACNZ. I’m not sure what the difference is.)
To be fair, a DAC can work as a sort of digital audio hub. If you have more than one device, and you want to route them all to your amplifier, you can do so through a DAC. I always have two computers on my desk: currently, this is my iMac, and my MacBook. I sometimes want to play music from one or the other for weird reasons (only the MacBook is set to use iTunes Match and Apple Music). So I can connect them both to the DAC.
It’s certainly worth trying a DAC, if you can. Depending on your computer, and your stereo equipment, it may make a difference. If you have a laptop, and want better sound from your headphones, the Cambridge Audio DACMagic XS (Amazon.com, Amazon UK) plugs into a USB port, and contains a small headphone amplifier. But at $189, or £100, it would be a waste if your headphones aren’t worth more than that.
Again, your stereo equipment should be good enough to justify such an expense. Most people don’t have good enough speakers; if I had a choice, I’d spend that money on better speakers before adding a DAC.
If you’re listening to music from your computer, the first thing you should do is connect an amplifier and real speakers to it. (I’ve updated both my amp and speakers since I wrote the article linked to in the previous sentence.) If you’re using standalone speakers, you’re probably not getting the best sound you can get. (Sure, if you’re using studio monitors, this is a different story…) And make sure that you’re listening in stereo.
The only case where you definitely need a DAC is if you listen to high-resolution music. Your computer’s internal DAC won’t be able to play the music at its full resolution, and you’ll need a DAC capable of handling the resolution of the files. However, this assumes that you think that high-resolution is worth paying more for; I don’t.
So, do you need a DAC? Probably not. Spend the money on good speakers. Do you want a DAC, just because? If so, there are plenty of models to try. Start at the low end; you may find that you don’t need to spend very much.