What do DACs, digital streamers, network audio players, CD players and other digital audio players all have in common? They play "digital music," obviously. But do you also know they all must convert the digital bits, 0's and 1's, into analog sound, the sound we hear? That's the job of the DAC (digital to analog converter) inside the unit.
There are essentially three parts to a digital audio product: the power supply, digital section, and analog section. The power supply regulates power coming in from your AC outlet to all the little components on the digital section circuit board and the analog section circuit board, as well as any display it may have. Some components have two separate power supplies, one for the digital section and, one for the analog section. Others have just one that powers both the digital and analog section. Whether using one or two power supplies, it must provide sufficient power to all sections at all times, playing a key role in the sound of the component.
A pretty good rule of thumb in determining if the power supply or power supplies is adequate, is the weight of the unit. If you pick up a unit and you could toss it across a room like a Frisbee, that's a pretty good indication it's not going to be all that great. If it has a wall wart or external switching power supply, that's also a fair indicator that it's not going to be a reference quality unit. If you pick up a unit and think, hmm… that feels pretty solid, that's a better indication of the quality of the component. However, if you bend over to pick up a unit and think, wow…that's heavy, that's a very good indication that a lot of thought went into the power supply design of the unit which also probably indicates whomever designed it had sound quality in mind as well.
Next is the digital section. This takes the incoming digital 0's and 1's and processes them accordingly. There are so many factors at play here. It's not just about converting the data, but also making sure that the space and pace at which the stream of the 0's and 1's arrives is as accurate as possible. For example, if the recorded data was 1 00 1 00 1 00 1, but the digital section processed it as 1 0 01 0 010 01, it wouldn't sound right (digital jitter). It's still the same 0's and 1's in the same order, but not processed in the same spacing and pace will cause poor sound. To overcome this, special clocks and oscillators must be used in the circuit. Unfortunately, many components skimp in this area and it can make a big difference!
Many customers also concern themselves with the DAC chip itself used in a given product to an unnecessary degree. There are a limited number of manufacturers that produce these DAC chips. The DAC chip is just one aspect of the digital section, just like a clock or oscillator. What's more important than the DAC chip itself or any individual item is how the DAC chip and other items are implemented into the whole digital section. Granted, the DAC chip is the heart of the digital section, but there are many other supporting digital components in the digital section that can and do greatly affect sound quality.
Did you know there are products out there ranging in price from $500 to $10,000 that use the same exact DAC chip? Will they sound the same? Nope. Not even close! The DAC chip is the actual "Digital to Analog Converter" which processes the 0's and 1's it receives and turns them into an analog signal. Why analog? Because the human ear cannot hear digital 0's and 1's, it can only hear vibrating waves of air, i.e., analog. Digital is a terrific way to store and transport information, but it's not music. It's a representation of the music. It must be converted to analog. Think of a handful of stones as digital 0's or 1's. Drop each into the same spot of water (the DAC) and see the waves ripple out from the center. The water ripples would be the analog sound created by the stones hitting the water. Of course, this is extremely simplified, but an analogy nonetheless.
Once the digital section processes the 0's and 1's and the DAC chip converts it to analog, you now have a 100% analog source. This is the reason why the analog side in many ways is more important than the digital section (assuming the digital section is also very good). It's the last stage of the process before being amplified and sent to the speakers. It's what gives a component its voice, flavor, character, etc. You want a digital product from a company that is renowned for digital, but especially renowned for analog circuits.
A digital product from a company that is known primarily as a digital company with little to no experience designing analog pre-amplification and amplification circuits may do half really well and the other half not so well leaving you with a product that is good, but unremarkable. Yet many times the analog side is overlooked in favor of a specific DAC chip, or digital format/resolution playback capability. Sure, you want a digital component that has a lot of headroom for digital growth, but not at the cost of a product that eschews the significance of the analog portion. Analog circuitry is an art form. I'm sure you can name a dozen or so famous speaker and amplifier designers.
What do they all have in common? Designing analog sound (yes, Class D and "digital" amps are in fact analog). On the contrary, I bet you'd be hard pressed to name more than one digital audio circuit designer. Not that they're not significantly important, but they are more engineer vs. artist. Digital design is a bit more math and computation, whereas analog design is more emotional and subjective, i.e. art.
So, in choosing your digital products (that must convert and process to analog), remember music itself is art. For that art to truly shine in its purest form, which is analog sound, pause and give thought to the component's lineage from an analog perspective. In doing so, you'll be much happier for it.