Things I don‘t know

(1) Many listeners can’t hear polarity reversal, even listeners with good systems and musical knowledge. As to why hardware doesn’t always offer it, it’s another feature that costs money to include. Why don’t (most) preamps have tone controls?

(2) The 10 MHz clock, last time I looked, was more designed to enhance long-term stability; at least, that was the view of the digital expert whose essay I read 1-2 yrs ago. The clocks in digital devices are getting better at the more critical issue, short-term stability.

(3) Galvanic isolation is a tool to achieve an end: low noise, distortion, etc. Perhaps manufacturers can achieve that in other ways. Measurements and listening of recent relatively inexpensive DACs (by SMSL and Topping, e.g.) indicate that to be the case. It’s the result that counts, not the means to get there.

(4) See (3). There is more than one way to get the job done. Maybe the ’optimal’ value of those things depends on other factors. Also, manufacturers are always looking for ways to distinguish their equipment, and it’s easy to say "our circuitry is special" and it’s hard to contradict. It makes great ad copy and can be used by reviewers who want to sound knowledgeable ("Audio Idiot explains that their special HAN transistors are faster and widely used in aerospace applications, where absolute accuracy is vital"). Finally, audiophiles show a disturbing tendency, encouraged by some reviewers, to think that anything more complicated, exotic, and expensive is better, so that always generates debate.

Another unfortunate characteristic of audio discussions is what was mentioned above: the tendency to look at the means, rather than the ends. Whether it's "Class A is better than ....", or "The ESS chips are not as good as ..." or "MOSFETS are ...", or "NOS DACs are the only ones that ....," in my view, there is far too much obsession over the mechanics, rather than whether the result sounds like music.

I used a Mutec reclocker for a while. It helped an older piece of gear appreciably, at least to my ears, but the reclocking degraded the sound of a newer, better (but less expensive) piece. Why, I don't know.

The main use of external clocking (other than profit) seems to be in sound studios with numerous pieces of gear that need synchronization. That's why consumer gear rarely has clock inputs.

I had an MC-3+ Smart Clock USB. The REF10 is more than I was willing to pay for something that I might or might not consider an improvement. My conclusion was that differences caused by reclocking will be system-specific (a pretty bland and safe conclusion).

Those interested in the subject might look at this 2010 comparison of clocks in the pro sound journal Sound On Sound. It said, among other things:

There's a widespread notion that adding a high‑quality master clock to a digital system will somehow magically improve its overall performance. While that might possibly have been the case in the very early days of semi‑pro digital converters where, frankly, some of the internal digital clock designs were pretty ropey, it certainly isn't the case today. . . . Today's converter designs generally work best on their own internal clocks, and most will deliver a slightly poorer performance when clocked externally. The very best devices will show no change in performance at all, because they have superb clock-extraction circuitry that can remove all traces of clock jitter and other external clocking artifacts, so they work just as well as when running on their internal clock.

As always, the questions are: Is there a difference? Is the difference an improvement? Is the improvement worth the price?