Saturday, July 12, 2014

Now I see it, now I don't....

Q: Do different DACs sound different? What kind of DAC should I get?

A: In theory the DAC should generate the exact identical analog version of the digital source, i.e. the sound is faithfully transmitted to the next link in the chain without any additions or subtractions. This is my definition of a transparent DAC --- a DAC that behaves "like it's not there".

But in reality that's not what happens, since the additional components that make up the DAC add their own "voices" to the signal, as does the DAC chip itself.

Having said this, most DAC chips use the same digital processing method (delta-sigma) and so sound remarkably similar to each other, whether they are made by Sabre or Wolfson or Cirrus Logic or Analog Devices, or any of the other slew of DAC manufacturers. There are some exceptions, for example old-style NOS (non oversampling) DACs sound different than their delta-sigma brethren, because they operate under entirely different principles.  But by and large when you read reviews that wax eloquent about the significant and substantial differences in the sound from one DAC chip or another, you are being subjected to, well, bullshit.

Why then is there so much variation recorded between DACs? Why are some dacs felt to be "warm" and others to be "cold"?  Well, the biggest reason is that it is a matter of perception: if you approach DAC transparency from an objectivist position, then for you a transparent DAC is ideal and if you are a subjectivist listener then the same DAC is "cold" or "boring".

If you are an objectivist, you want the faithful transmission of a signal, then the coloration imparted by the analog component fo a DAC like the Cambridge Audio DacMAgic 100 is anathema.

And if you are a subjectivist, the coloring of the sound excites you just as much as the faithful transmission of the signal, and the transparent output of a DAC like the ODAC might be "bland" or "cold" or "not energetic" to you. I would argue that for such a subjectivist listener, the tonal variations offered by a tube DAC might actually be more pleasing than "the truth the whole truth and nothing but the truth" offered by a transparent DAC. If you don't believe me, ask anyone with a Grado.

Further, a DAC can pick up floor noise -- hiss from, say a laptop via the USB port, that the muddies the sound profile a ta. But the same DAC may be deathly silent when plugged into a desktop USB. Does that mean that the DAC is transparent when it's connected to a desktop but not to a laptop? By my definition, yes.

You can get around noisy USB by including a good power transformer with the DAC itself. But these are expensive, and can drive up the price of the DAC. One DAC brand that has been touted for its sonic neutrality, to the point of becoming a standard reference whenever the term "transparent DAC" rears its head, is the Bench mark DAC1, which is an expensive option.

So from price-performance perspective, does buying a DAC1 make sense? Probably not. You can get a relatively transparent DAC as cheaply as $100 - the Schiit Modi (which uses a wallwart for power), or alternatively the ODAC (which uses USB power, and is priced at $150) and these are perfectly acceptable price-performance options to something like the DAC1.

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