Starting off in the world of DACs (Digital to Analogue Converters) can be a nightmare for the uninitiated. In fact, unless you’re armed with a little foreknowledge, the choices can seem insurmountable. I mean, you would never go out to buy a boat without some idea of your requirements – a small sailing dingy or a multi-million pound yacht?
To narrow down the choice, the age old adage of ‘good, better and best’ can readily be applied alongside a good dose of basic common sense and a little knowledge of the fundamentals of digital audio coding. Further to this, a quick analysis of your own requirements — IE portable, desk-top or full blown hi-fi system will start weeding out the right product for you.
A ‘good’ DAC…
Who’s this for? Well, generally speaking, anyone who wants to improve the sound quality of their audio feed from the likes of a laptop, tablet or smart phone. Probably, the file formats that need to be converted will be pretty basic. Here, I don’t mean MP3 (but even those will probably sound better than the native source can amplify). I mean audio streams from the likes of Spotify that are compressed audio being encoded at reduced data rates to save data bandwidth, so it doesn’t cost a fortune on-the-go via mobile connections. I also mean some of the standard data streaming from Internet radio broadcasters form the likes of TuneIn Radio. Many of these file formats are basic PCM encodings at low data rates up to like 300kb/s.
‘A good DAC such as the entry level ZEN DAC from iFi can render these basic encoded files into an analogue signal passable for reasonable listening. Typical price points for ‘good’ DACs would be around the £100-£200 mark. Feature sets can vary enormously from basic Digital into Analogue out with no functions, to very useable sound enhancement features. Examples of features would be the bass boost and power match for power hungry in ear monitors found on the ZEN DAC. DACs at this price point should also be looking to the next level of digital audio decoding to allow for ‘hi-res’ CD quality audio if possible — IE minimum 16bit/44.1khz, although most should do 24bit/48khz PCM (WAV files).
Moving on up…
Moving up the ladder to ‘better’ we should see a significant jump in the kind of data file decodable as well as serious attention to detail in terms of construction quality and input/output connection capability. Of course, with these additional features there comes the added price/value consideration. One should ask, “Am I really going to be accessing a lot of hi-res files?”.
If the answer is yes because you just got gifted a Tidal streaming subscription for a year, then an upgrade to a better DAC is a must. Better DACs are probably in the region of £400-£1500 and will offer a far wider range of data file decoding as well as inputs/outputs, just like the iFi micro iDSD Black Label. Not only can this unit decode standard CD quality, but also hi-res like PCM 24/96khz and 24/192khz – both of which are found to be at the upper specification for recording direct to computer in the professional audio world. Beyond this we also start entering into data files targeted specifically for detailed hi-res listening such as DXD 24bit/384khz, DSD 64 and 254 as well as MQA.
All these formats take the sound quality way beyond CD format and allow the user to get far more from their system. DACs in the ‘better’ range can still be employed as simple headphone/DAC combos, but due to the fact that they have more input/output connections, they can also be deployed in more sophisticated systems. The micro iDSD Black Label not only has USB inputs but also SPDIF allowing for Coax or Optical digital connections from equipment such as CD/DVD and portable players. Indeed, most TV monitors now also have optical outputs and the data stream from an HD broadcast is better than CD quality. Outputs are also important and, in addition to the standard headphone outputs (normally higher spec 6.3mm jacks as well as 3.5mm), you often finds RCA connectors to feed into a hi-fi system or 3.5mm line outputs for connection to music systems.
Simply the best…
Moving beyond the plethora of ‘better’ systems we start to enter the world of ‘best’. Here, we should remember that just buying the ‘world’s best DAC’ is not going to necessarily produce stunning sound. It’s a bit like buying a Ferrari and running it around the farmyard! No, we actually need a good racing track to get the best from it. In audio terms, this means we need to be looking at equipment connected to our DAC that will enable it to ‘sing’. Quality headphones, amplifiers and loudspeakers are a must. We should also look at the power conditioning requirements of our system as now we are entering the elite when it comes to sound file quality playback. Every little noise and distortion may be heard if the system is not a balanced one. True high-end DACs can often sell for over £50,000 but an extremely competent unit can be had for an investment in the region of £2500-£5000. Take the iFi Pro iDSD for example.
At this DAC level we should be able to decode any digital-audio file format available today from the lowly CD res of 16bit/44.1khz right through to the super-high resolutions of single bit encoding from DSD 512 and DSD 1024 as well as the top PCM sampling rates of 384kz-768khz and at bit depths (digital volume) up to 32 bit.
Certainly, the ‘best’ category DACs are likely to be the preserve of desktop and system integrated units with a plethora of inputs/outputs such as RCA, balanced XLR, headphone connections supporting both balanced and single ended connectors as a well as a multitude of input source connections. These might include USB, data cards like Micro SD, USB-A source, AES, SPDIF and Wi-Fi, to name but a few.
That being said, each category of DAC, ie portable or desktop, will have its stand-out best contenders. The iFi xDSD offers many of the hi-res file decoding features mentioned above but in a portable compact design and even includes Bluetooth interface suitable for ‘on-the-go’ use.
Not all DACs are created equal…
At all these price points and levels not all DACs are the same. The fundamental converter chip is vital to the quality of the audio stream being produced. Industry leaders such as Burr Brown and ESS Technology with its SABRE range lead the way. However, it’s not just the chip set itself, it is how it is used alongside the surrounding circuitry that is also supremely important. Remember the Ferrari analogy above!
At iFi we support our DAC circuit designs with balanced analogue output stages, even in many of our entry level systems, to achieve better signal-to-noise ratios and higher output SPLs (sound pressure levels). Further attention to the digital circuit around the DAC chip with additional clocking enhancements reduces jitter and timing effects to give a cleaner more detailed sound.
Good, Better, Best? The only real way is to compare systems is to have your trusted reference sound files at the ready. Ideally, use a minimum of 24/96khz and certainly NOT MP3s or you’ll never hear the difference!