The title is:"There's No Such Thing As Digital..."

I can see lots of reasons to quibble with it. It leaves out a lot of pertinent info about digital. Digital is of course just an analog waveform as all electricity is, however sometimes digital is just digital and the analog aspect is unimportant. Also, digital has attributes that analog does not have, such as reflection effect on jitter, signal integrity, current-path characteristics and rise-time effects etc.

Steve N.
Empirical Audio

"I didn't think there was any such thing as 100% jitter free? I thought all timing sources had jitter?"

There is no such thing. Marketing BS and an outright lie.

"At what point does that become audible? Can our ears really detect say 400 pico seconds of jitter?"

Depends on the system. Resolving systems can easily demonstrate difference between 20psec and 100psec of jitter, and it's not subtle. Resolving means ultra-low noise floor and distortion. Usually no active preamp to achieve this.

"I also have quibbles with this article. It seems to concentrate on DAC clock, that is usually not that bad, placing less attention to delivery of the signal."

That is interesting, given that many DACs don't have an internal clock, except maybe for the Async USB interface master clocks. These are usually the important ones. This is where the jitter starts in a USB system. It will even have an effect on additional reclocking.

"I have DAC with reclocking built in and it is very clean sounding but Steve found that external reclocking works better."

That is primarily due to the separation of power systems, putting the master clock on its own power system, separate from the DAC circuits. If you can do this effectively inside the DAC, that is fine too. Pretty awkward to have two power cords though...

Steve N.
Empirical Audio

"Steve, you're missing all network DACs including Ethernet, Firewire, Wireless etc."

These are usually not called DACs, but music processors or servers etc., but you are correct.

"You also forgot about asynchronous reclocking DACs.

Typical DACs contain Phase Locked Loop (PLL) that contains adjustable oscillator and phase detector."

These may be typical, but I didn't forget about these, I totally ignored them. I don't even consider resampling DACs because the effect of resampling is so damaging to audio quality, even using a high-quality clock, which most don't have. I would never design such a DAC. Once you have this, no matter how good the input source is, the internal clock and resampling wrecks it IME. I have modded more than a dozen such DACs in the past 12 years, so I know how this sounds.

Steve N.
Empirical Audio

"You probably think about oversampling and that is different. Pretty much every CDP contains PLL."

This is why I don't use or recommend CD players anymore. There are a few that are computer-based that might be okay, depending on the clock quality etc.

"Even asynchronous rate converter based DACs (upsampling DACs) like my Benchmark have some form of PLL to make signal stable enough for upsampling."

I probably have 100 modded DAC1's out in the field. I know it well.

"Usually PLL is inserted somewhere."

Not in the best DACs. The jitter of a free-running clock will always beat a PLL.

Steve N.
Empirical Audio

"I've yet to hear a PC system easily trounce a really good CDP."

If you buy the USB DAC du-jour, you will not get there either. It takes a bit of work, including selection of the best computer platform (not a "music server"), the best playback software and ripper and the lowest jitter USB converter or DAC with USB interface. All of these things are doable and there are plenty of recommendations out there.

It is not cheap though. In order to compete with for example the dCS Vivaldi, you have to spend at least $10K on the computer, USB interface, DAC, power supplies, cables and software.

The good news is that spending $5K on a CDP will not get you the SQ of spending the same $5K on computer and DAC IME.

Steve N.
Empirical Audio

Kiwi - usually if its not musically engaging, this is jitter and the USB interface is at fault. Upsampling hardware can also be at fault, both for the clocks and the algorithms.

Here are some systems that are musically engaging and not megabux:

iPod or iPhone and:
Pure I20 docking station - $89.00
Synchro-Mesh reclocker - $599.00
Hynes power supply for Synchro-Mesh - $600
BNC cable - $250
Concero DAC - $600
Total = $2138.00

Sonos - $400
Synchro-Mesh reclocker - $599.00
Hynes power supply for Synchro-Mesh - $600
BNC cable - $250
Concero DAC - $600
Total = $2449

used Mac Mini 2009- ~450 with SSD and DRAM
Mac Mini Hynes power supply - $900
USB cable - $400
Off-Ramp 5/Turboclock/S/PDIF Hynes reg - $2249
Hynes supply for Off-Ramp 5 - $600
BNC cable - $250
Concero DAC - $600
Total = $5449.00

used Mac Mini 2009- ~450 with SSD and DRAM
Mac Mini Hynes power supply - $900
USB cable - $400
Off-Ramp 5/Turboclock/HDMI Hynes reg - $2249
Off-Ramp Hynes power supply - $600
HDMI I2S cable - $250 from partsconnexion.com
Wyred 4 Sound DAC2 - $1500
Total = $6949.00

As for the linear regulators: IF they are not really fast-responding, then not so great for digital. The Hynes supplies that I design are extremely fast responding. If they are based on off-the-shelf three terminal regulators, this does not cut it IME.

Steve N.
Empirical Audio

"The whole "gray area" issue(which Hansen eventually admits is not really an issue in a well implemented system), the issue of running multiple processes on the computer, the potential of noise on the grounds, jitter (in all its forms), RFI etc. have been discussed over and over again. A lot of progress has been made on all these fronts with async USB, galvanic isolation, attempts to minimize CPU usage, much better jitter control, etc. Unfortunate, it seems that after several years of figuring out many issues and addressing them, we are now stuck more in a discussion phase than in an significant improvement stage."

There have been some breakthroughs. For instance, it is pretty much accepted that the reason that USB cables make a difference in Async interfaces is common-mode noise. This can be addressed with CM filter or galvanic isolation.

Unfortunately, there are still issues with different SQ from different playback software and different computer hardware when using USB. It makes no sense that improving the power supply for the computer would make a difference, but it does, even with Async USB and galvanic USB isolation. These will remain a mystery for a while I think.

One way to address this is to use networked audio streaming. The downside is that you are trapped into the implementation and playback software. It is also usually limited for sample-rates.

Steve N.
Empirical Audio