Is no DAC the best DAC?

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I’ve been answering a lot of great customer questions on Ask Paul. One of them was a simple misunderstanding, but it sparks good dialog.

On the DIY forums, a poster suggested he was converting digital audio to analog without the benefit of a DAC and the question posed to me was, “Is that possible?” The answer should be a simple “no” but then it’s never quite that simple.

Let me first explain what the poster on the DIY site was doing: converting DSD to analog with little more than an output transformer. Thus, he didn’t need a “DAC” to make music, he needed only a single part.

DSD is very different than traditional PCM. If you were to try the same technique of decoding PCM with a simple capacitor, you’d get nothing but noise (if you got anything at all). This is because PCM isn’t anything close to analog, while DSD is as close to analog as any digital format can be. Look at PCM on a scope and you see nothing recognizable as music (it’s a code, after all). Try the same thing with DSD and you can actually see the music.

This difference is one reason why our digital guru, Ted Smith, converts everything to DSD in our DirectStream and DirectStream Junior. Their output stages are essentially simple low-pass filters (like the transformer I mentioned earlier). DSD is already close to analog and requires very little post-processing.

In direct answer to the reader’s question whether it’s possible to play digital music without benefit of a DAC, I would answer, no. Anything used to convert digital to analog is, by definition, a DAC.

This is a subject I go into in some detail in this video.