Should you buy a DAC?
The days of analogue music are long gone. ‘Yes, but vinyl is getting a revival’, I can hear you argue. True, but in the greater scheme of things, there is no going around the fact that while the vinyl market is growing, it is still a niche market reserved for the audiophiles and nostalgic few. Digital music (with all its faults) on the other hand is everywhere. And that’s asking for a DAC.
It doesn’t matter whether we talk about music on a CD or music streamed from Spotify, Apple Music, Google Play, and other corners of the cloud. Digital music has one main denominator: You can’t listen to it in its digital form. It needs to be ‘translated’ back to sound.
We need to explain a little: simply put, a digital signal is created by taking the analogue sound wave and taking precise measurements of ‘amplitude’ (a degree of change in air pressure that causes the sound wave) at highly regular intervals (called the ‘sampling rate’). The more frequent these measurements are taken and the more accurate the amplitude wave measurements are, the more accurate the sound is translated into its digital form (represented as binary numbers-0’s and 1’s) and the more accurate the recording of information is.
There are different encoding systems dealing with this process of creating the digital signal, PCM (Pulse Code Modulation) being the most popular one. But there are alternatives like DSD (Direct Stream Digital) that continue to have a small but loyal following because of the higher sampling rate. Not all DAC’s support the DSD encoding system, but the Chord 2Qute and Mojo for instance do.
To make the link with the blog about hi-Res audio a few weeks back: when recording a standard CD, say, a sample is taken 44,100 times per second. Each of these samples is measured to an accuracy of 16 bits, storing the results in a 16-digit binary format.
Record a high-res track, on the other hand, and you’ll take a step up to 24 bits, with a sample rate taken 192,000 times per second.
It is the DAC’s (Digital to Analogue Convertor) job to translate the binary format of the digital recording back to its original analogue version as accurately as possible. Obviously, the more information stored in the digital format, the more accurate the ‘reconstruction’ of the original analogue sound.
There’s a tiny DAC inside your phone, and another one in your computer’s sound card. There is also a DAC in your AV receiver, CD-player or blu-ray player. However, especially for the small devices, with space that limited and companies always looking for ways to keep production cost at a bare minimum, quality of the internal DAC’s is not always up to scratch. So, introducing dedicated external DACs.
It will come as no surprise that not all digital-to-analog converters are created equal. The DAC in any audiovisual item can be the difference between a great and an average product.
That said, a lot also depends on the overall implementation and engineering. A good DAC chip that is badly integrated, is not going to make a showstopper AV product.
We use different DAC’s for different purposes: we have DAC’s for headphones, DAC’s designed to connect your home audio system. There are wireless DAC’s, there are portable DAC’s. You name it, it exists.
So, the question is: What is what and maybe even more importantly; which one is the right one for you? Or (dare we say it): do you really need one?
To start with, it is always good to be reminded that an audiovisual system is only as good as it’s individual parts. If your source material is poor, no DAC is going to provide an out-of-this world sound experience. That said, any half decent portable external DAC that does not have to cost the earth is going to make your music worlds better than your computers built-in DAC chip.
So back to our burning question: do you need a DAC?
Let’s just start with saying that DACs are a fairly mature technology and most good quality AV receivers, CD players, streamers and blu-ray players have perfectly adequate internal DACs for the average music lover and home theatre enthusiast.
But as we said earlier, while just about every AV item has an internal DAC, poor quality circuitry can mean unwanted noise during playback. Here’s how to know: listen to the quieter sections in your track. If you can hear a hiss or your playback is disrupted by noise, you need an external DAC, provided that the quality of your cables is fine and that you have ruled out interference.
And then there is ‘jitter’. Jitter refers to an error in timing between your source and your internal DAC (‘digital clocks’). This results in a slightly off or warped sound. Jitter is a fairly common problem. The digital clocks found in dedicated hi-fi DACs tend to be more accurate than those used in bread and butter AV items and the average PC, iphone or mp3 player. Which is the main reason why many of us find an external DAC an improvement to their set-up.
One particular situation where an external DAC is especially recommended is with the use of headphones.
Apart from the above mentioned issues like jitter, loudness can be an issue especially for expensive and hard to power headphones like planar magnetic headphones. In most cases a headphone amplifier is going to improve your audio experience. Most headphone amplifiers have DACs built-in to make it easy to address two different issues in one go.
So say you have decided you need an external DAC. The next question is which one to choose?
As we have already established, external DACs come in all shapes and sizes, offering options for all budgets. To find the right one for you it’s quite important to think about how you want to use it.
Is portability important? Do you want to go as small as a compact USB DAC like the M2Tech hiFace DAC or Audioengine D3 or do you prefer a pocket-sized unit that connects via a separate USB cable like the Cambridge Audio DACMagic XS?
Fiio offers a very affordable range of portable DAC/amp combos especially designed for headphones. A step up is the Chord Mojo.
Desktop DACs like the Audioengine D1 and the Cambridge Audio DACMagic 100 also connect to your computer through USB. Unlike portable DACs, some desktop models need power to operate. Certain desktop DACs offer line-level audio outputs for connecting powered speakers or an amplifier. You can also connect an external CD player or network streaming device to a desktop DAC. Some like the Chord2Qute also offer a headphone output for private listening.
Fiio, Audeze and Sennheiser also offer dedicated desktop headphone DAC/amp options at several price points.
Wireless DACs like the Audioengine D2 broadcast digital content to an audio system in another location. These DACs typically use a transmitter that connects to your computer through USB. It sends the digital information to a separate wireless receiver. Once the audio is received, the digital signal is converted. The wireless receiver connects to your stereo or amplifier through RCA cables.
Component Hi-Fi DACs like the Audiolab M-DAC+, the flagship Cambridge Audio Azur 851D and the T+A DAC are designed to connect to your full-fledged home audio system. You’ll find even more inputs and features, often ones searched for by the more serious audiophiles and they very likely support the full range of high end High-res music formats or Bluetooth connectivity. They are ideal for two-channel stereo systems. They are also good to use with high-end home theater receivers that offer a direct mode.
Component DACs offer the widest range of connection options. Some models like the Cambridge Audio DACMagic+ even provide a volume control that allows them to be used as a preamplifier in a digital sound system.
So, do you need a DAC? Let’s just say that there are a number of reasons to buy a DAC, the best two are to eliminate noise from your source and to combat jitter. If these are your issues, an external DAC definitely is the solution.
Whether you need a full blown component DAC or whether you can get by on a portable one very much depends on your set-up, your budget and your requirements.
We highly recommend an external DAC if you are a regular user of headphones.
Let us know if you would like help deciding. We are only a phone call away and we love to help out.
Source: What Hifi, Crutchfield, Audiolab, Cambridge Audio, Chord, T+A, Fiio, Audeze, Audioengine, M2Tech