Can you review a Synchro-Mesh S/PDIF re-clocker?

[Empirical Audio]

OK, so those charts do seem to show a nice reduction in deterministic jitter.
Is that at 5.644 MHz?
Any indication that the jitter at that scale would have resulted in actual bit errors in the audio signal transmission?

No.

Any indication that the heavy-handed reclocking doesn't force its own bit errors?

Heavy handed??? There are no bit-errors. This is checked by my receiver in my DAC. if there are any errors, it mutes.

Wouldn't a BERT (Bit Error Rate Tester) be better suited for the purpose of testing?

Sure, knock yourself out. There are NO BIT ERRORS.

As far as I am concerned, jitter doesn't worry me a bit as long as it does not introduce bit errors.

Then your concerns are misplaced. A survey of industry DAC designers about 5 years ago showed that 90% of them felt that jitter was the #1 thing that impacts audio sound quality. I am with them. The #2 issue is poor digital filter design. This is why NOS DACs are so popular.

 

[Empirical Audio]

As he's basically advocating forum members to buy his products without any proof of quality I think he should be confined to desperate dealers section and he can freely brag about his beliefs from there.

Where and when did I solicit one of you skeptics to buy any of my products?? Show me.

 

[SIY]

Where and when did I solicit one of you skeptics to buy any of my products?? Show me.

"However, it is literally a no risk thing to buy this for $150 on Amazon and try it in your own system. You can return it for free if it does not make any difference. I have improved many friends and neighbors systems with this thing, as well as my own HT system. These people don't use anything but the wall-wart. Like I said, it's a no-brainer."

 

[Empirical Audio]

"However, it is literally a no risk thing to buy this for $150 on Amazon and try it in your own system. You can return it for free if it does not make any difference. I have improved many friends and neighbors systems with this thing, as well as my own HT system. These people don't use anything but the wall-wart. Like I said, it's a no-brainer."

It's not my product. This is made by a company called iFi. I don't re-sell it either.

 

[Veri]

"However, it is literally a no risk thing to buy this for $150 on Amazon and try it in your own system. You can return it for free if it does not make any difference. I have improved many friends and neighbors systems with this thing, as well as my own HT system. These people don't use anything but the wall-wart. Like I said, it's a no-brainer."

he meant the iFi ipurifier for spdif there, his products do not cost $150. (haha)

 

[SIY]

Ah got it, thanks for clarifying.

 

[amirm]

Then your concerns are misplaced. A survey of industry DAC designers about 5 years ago showed that 90% of them felt that jitter was the #1 thing that impacts audio sound quality.

You would think they would put their energy together, run one controlled listening test and publish it.

Even that aside, these DAC designers rarely publish any jitter measurements. You know, with full spectrum and such so that we can determine audibility. They talk about jitter, but they don't measure and publish....

 

[Empirical Audio]

You would think they would put their energy together, run one controlled listening test and publish it.

Even that aside, these DAC designers rarely publish any jitter measurements. You know, with full spectrum and such so that we can determine audibility. They talk about jitter, but they don't measure and publish....

Very true. I'm not adverse to AB/X tests, as long as I use my system and the listeners are trained listeners. I don't trust other's systems, even reviewers. I have heard them in person and most are dissappointing.

An AB/X test was done by a magazine in Canada to prove/disprove this white-paper I wrote a few years back:

http://www.positive-feedback.com/Issue14/spdif.htm

The technical analysis should be enough, but listening tests are really needed to prove correlation of jitter and the analysis. The AB/X proved me right.

Steve N.

 

[Empirical Audio]

Very true. I'm not adverse to AB/X tests, as long as I use my system and the listeners are trained listeners. I don't trust other's systems, even reviewers. I have heard them in person and most are dissappointing.

An AB/X test was done by a magazine in Canada to prove/disprove this white-paper I wrote a few years back:

http://www.positive-feedback.com/Issue14/spdif.htm

The technical analysis should be enough, but listening tests are really needed to prove correlation of jitter audibility and the analysis. The AB/X proved me right.

Steve N.

 

[pkane]

It's not my product. This is made by a company called iFi. I don't re-sell it either.

I have one of those. Also had a Mutec 3 USB. They made a big difference with my mid-90's DAC. No difference with any of the more modern DACs. No measurable difference that my ADC can detect, and no audible one that my ears can. I sold the Mutec, and I'm now using iFi between the cable box and the AV receiver...where it is also not making much of a difference. But it does make me feel better knowing that all that jitter is being reduced.

 

[amirm]

An AB/X test was done by a magazine in Canada to prove/disprove this white-paper I wrote a few years back:

http://www.positive-feedback.com/Issue14/spdif.htm

The technical analysis should be enough, but listening tests are really needed to prove correlation of jitter and the analysis. The AB/X proved me right.

I read that years ago. And used to reference it myself. Then I tried to measure that effect and could not. So I stopped referencing it. I should repeat it one of these days.

Meanwhile, where is the listening test results you mention?

 

[Empirical Audio]

I read that years ago. And used to reference it myself. Then I tried to measure that effect and could not. So I stopped referencing it. I should repeat it one of these days.

Meanwhile, where is the listening test results you mention?

It is UHF magazine. I have contacted them. It's been so long, I hope they even remember....

Steve N.

 

[Empirical Audio]

I read that years ago. And used to reference it myself. Then I tried to measure that effect and could not. So I stopped referencing it. I should repeat it one of these days.

Meanwhile, where is the listening test results you mention?

The analysis was based on a "typical transport" of the time, which had a risetime of around 3nsec. If your source is a lot faster than that, you may not get the same result. I still find however, with 400psec risetime on all of my products, that jitter measures better with a 1.25m cable as opposed to a 0.5m cable, so I still recommend 1.5m for all digital connections, even USB and I2S.

On another topic, the correlation of the direct jitter plot and audibility is something I have been working on for a while. It's difficult to characterize the differences in audio quality when we are talking about small differences in jitter, however I have made some observations. One is that if there are two distinct peaks in the jitter plot, the sound quality tends to have a slight "hardness" to it, even if the absolute jitter is extremely low. Other than this, just noticing that the clarity and imaging improves if the jitter is smaller. I was hoping to compare the spectrum of the jitter and the shape and width of the distribution histogram and derive some conclusions, but it's been elusive. Correlation of jitter to audibility has so many variables, including spectrum, relationship to the music waveform, amplitude and distribution. Any or all of these probably change the audible effect.

 

[Krunok]

I have always had more measurements of my products on my site than any other of my competitors. Show me one that posts directly measured jitter plots, or even jitter plots after their D/A....

However, your measurements constantly fail to show the most important thing - the effect on DACs analog output signal. Which is understandable, as there is none. Except of course the effect only you can hear with your Supermans hearing.

 

[PierreV]

Sure, knock yourself out. There are NO BIT ERRORS.

Ugh... OK.
Thank you very much, Sir.
And please accept my apologies for asking, Sir.

 

[Krunok]

I read that years ago. And used to reference it myself. Then I tried to measure that effect and could not. So I stopped referencing it. I should repeat it one of these days.

Meanwhile, where is the listening test results you mention?

Did I get this right? He proved right with blind test something you weren't able to measure? Ehhh.. here we go again..

 

[AresHarvest]

I am watching this thread with great interest. And popcorn.

 

[solderdude]

Steve, what do you think/hope to get out of Amir's AP measurements ?

Surely you must already know the DAC output is not going to change as DAC's today reclock anyway. In fact you already mentioned that.
Yet that's what most likely will be measured.
You also mentioned audio measurements aren't 'good enough' so why ask to have Amir's AP measure it anyway ?

Could you describe WHAT exactly you want measured/verified and where that has to be measured acc. to you.

In your OPsts you already mentioned you only want the digital signal measured (I assume waveform only with correct in-output matching and your own cable).

 

[restorer-john]

I can confirm that the member ignore function hides this entire thread. Just tried it for the first time and it really works.

Just a heads up.

 

[garbulky]

Amir recommends in his iPurifier review:



Well, guess what? My latest USB converter is XMOS based and has full galvanic isolation. The isolation did not make a big difference in my system, but my ground-loop problems are minimal, if any. I use a LPS for the USB power and this seems to make some difference. I don't believe that galvanic isolation is a major panacea anymore, although it's obviously beneficial. Designing an isolated USB front-end that can be powered from the USB cable actually cripples it a bit because of the current limitations of the USB power. The designer is forced to minimize the capacitance on the power feed and must use many small SMPS to power this section. Using an external fast LPS for USB power seems to compensate though. This kind of LPS can cost as much as the DAC however.

What did make a huge difference is the SOtM USBultra regenerator on the USB cable. I don't know what this thing does, but it does it really well.

Steve N.

I was curious as to your system? I am looking for great resolving setups.