.? Digital Reclocking and syncing clocks does anyone know the correct Answrrsb

What I meant to say is  the digital stream is never perfect, But the much more costly units  have many ways to correct Jitter or timing errors ,

What  you are saying is wrong. There is no jitter on USB of Ethernet inherent in the data transmission. None, nada, zip. There is no jitter or timing errors to correct. That is why low cost DACs, literally ones that cost <$200 are able to do THD+N, SNR <-110db, and IMD, even multi-tone IMD at very low levels.

Even with SPDIF, those DACs are able, though PLL receivers and any number of chip based methods reach SNR, THD+N, etc. <-110db. They will even do it with TOSLINK.  Cost means nothing. There are a lot of expensive DACs that can't do that. Think of how much experience, and knowledge goes into those DAC chips.

this too is where a DDC  -Digital to Digital converter to clean up the incoming digital stream and eliminate timing errors before it goes out to the dac , the easier the dac can read the less error correction s needed , On the better units they buffer the signal ,like ram  ,there there is FPGA  ,it’s exact implementation is above my Digital 

FPGA is just a bunch of fast digital logic. It has no inherent advantage. There is nothing to clean up with USB and Ethernet, and again, with SPDIF, if you are already <-110, or better, what exactly are you cleaning up?

@itsjustme , by Consanant and Dissonant distortion, do you effectively mean harmonic distortion and intermodulation distortion?  I could see dissonant distortion also meaning aspects of unpleasant harmonic distortion.

When those distortions go close to 0,we don't hear them, but you are correct, we may not like the result. Some people like tone controls, and distortion can also be used to affect tonal balance in a pleasing way. I actively play around with added distortion on my setup, preferring it with some music/listening levels. I just do it in DSP so I can turn it on/off.

The LM49720 does not suck. It a properly designed circuit, it is a straight wire with gain effectively. The THD, IMD, noise, etc. is low enough to be difficult to measure. The 1612 is similar. Put it in the wrong circuit, and conceivably it will have issues. They do what they do. They do it very well .... but .... no matter what they claim, a large portion of audiophiles don't want a faithful recreation of the recording, they want something different.

Here is a big question , say you have a very good dac with over clock ⏰, 

Logically, if you have a "very good DAC", but you need some external "reclocking" device to make it work properly, is it a "very good DAC"?

The Denafrips clock are a proprietary inter-device clock. This is different from 10MHz external clocks.

If it is USB, then there is no connection between the USB clock and the clock used for the DAC output, so what is being "cleaned". With USB, there is definitely the potential for power supply and ground noise to get on the audio output of the DAC, but that is not a clock issue. If you started with a "very good DAC", I would hope it already addresses this issue.

What are you using for your digital source? Old CD players, where the clock was synced to the mechanism, and the error correcting could even come into play often had high jitter. If your "very good DAC" is not "very good", perhaps if you are using TOSLINK, you could be introducing jitter, but that is happening at the DAC, so how is a reclocker going to help that. If you are not using a CD player, then we can assume you are streaming, and streaming sources are already starting with very low levels of jitter. Can your "very good DAC" not use an already low jitter source and give you good audio?

A "very good DAC" could transformer isolate the SPDIF, or it could have an isolated SPDIF section, which would remove the noise issue.

Is an external 10MHz clock, which has to transmit that clock via a cable, that connects to some IC in a DAC, that has to deal with the electrical noise between the two chassis (clock and DAC) going to be, without question, better than the internal clock in a "very good DAC"?

In some systems, and with some DACS, noise isolation, power supply and grounds, can be beneficial, but that is almost always about noise directly getting into the analog output, not something that impacts the DAC circuitry and especially not in something designed right. Hence if you don't hear noise that you associate with power supply/ground loop issues, then it is unlikely you have a problem.

The act of reclocking is suspect and for USB does not have meaning. If your DAC needs the input to be "reclocked" then perhaps your DAC is not as good as you thought.

@jimob ,

I am a little disappointed in Denafrips sending you a review that says,

ll DACs are not created equal, especially when it comes to dealing with noise, jitter and USB. For example, the Holo Audio May DAC (see review) was run through its measured paces by John Atkinson at Stereophile where he found, “In almost every way, the HoloAudio May (Level 3) is the best-measuring D/A processor I have encountered”.  According to GoldenSound’s measurements and his interpretation thereof, the May DAC’s FIFO buffer did a great job of rejecting word-clock jitter. I would assume, based on its measured performance and my listening impressions, that the Holo May DAC may not need a DDC like the IRIS since it does such a great job with USB all on its own. [footnote 2]

Almost every USB DAC made today, from probably $25 and up, is asynchronous. That means that the USB data transfer is independent of the DAC clocking. Virtually every USB DAC will have a buffer/fifo now. That the reviewer is not aware of this is shocking, but I am not surprised.

Denafrips collects and distributes these reviews just like everyone else, and gladly sends them to anyone who will listen. They appear to make great products, but they are counting on the uneducated consumer (and reviewer) as much as anyone.

Reclocking cleans  digital signal  and makes it easier to read when the dac get the data puts it in a buffer then does a bunch of other things before final conversion ,in good dacs a lot of information way over my digital knowledge base .

It is not over my digital knowledge base. This "cleaning" the digital signal is a very suspect statement (not by you, but claims by people selling it). Even the cheapest streamer has a very clean digital signal output, with potentially the exception of some electrical noise which is not difficult to filter out. That can in rare instances affect SPDIF, but a good DAC should already isolate SPDIF. It will not effect the data, but it may introduce small amounts of jitter, something most modern "good" DACs eliminate without much trouble. We are talking streamer level jitter now, not the old large amounts of jitter from CD players. With USB, this is not remotely an issue. Your USB will work or not. If it works, the data is getting there, totally uncorrupted, and as noted, the timing on USB has no impact on the DAC clock.

I am just copying these lines for posterity. I feel no need to comment on your knowledge and what you bring to this discussion. I will simply let them speak for themselves.

lordmelton:  And BTW re-clocking is for the computer or source not the DAC : )

lordmelton: The enemy of every DAC is jitter and even if a DAC has zero jitter it can't compensate for the jitter coming in.

Would it not have been easier to just say "I have no idea, whatsoever, how a DAC works"?

lordmelton: The enemy of every DAC is jitter and even if a DAC has zero jitter it can’t compensate for the jitter coming in.

This is the problem @jimob , you have people who don't even know the most fundamental aspect of how a DAC works, commenting heavily and with authority, and at the same time making fun of people who actually do. Hard to navigate towards the correct answer working under that premise.

one thing is for sure the best measurements don’t always sound the best .

A perfect example A vacuum tube amp,or preamp measure no where near as good as even a mid fi amp but it’s distortions being even just sound right to the ear 

No they do not, and I would never claim they do. They can tell us how something compares against a reference and they can tell us whether something actually is able to do what it claims (other than sounding good). I won't type the details, but my system is very accurate, very low noise, and very low distortion (turntable excepted due to natural limits). Then I use signal processing to twist it and turn it to suit the music, mood, listening level, and even who I have listening with me. Same goal as anyone else, just a different way of getting there.