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

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SIY

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Please define what you mean by "dynamic response." Since every test signal I'm aware of has "changing signal amplitude," what you've written there is unclear.

And no, the important thing is the analog output of the DAC. That's the electrical signal which is converted to sound.
 

amirm

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Steve, ultimately all of us care about one thing and only one thing: whether the analog waveform coming out of our audio system is changed/improved by anything upstream. That measurement remains analog by definition.
 
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Empirical Audio

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Please define what you mean by "dynamic response."

And no, the important thing is the analog output of the DAC. That's the electrical signal which is converted to sound.

Ultimately, yes.

Dynamic Response is the ability of the circuits to reproduce a transient waveform accurately, at any amplitude. You can have transients at low amplitude and also at high amplitude. Reproducing both of these accurately is the challenge.

Steve N.
 

SIY

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So how is that not tested with an AP? (I assume you're aware that the "transients" are bandwidth limited).
 

RayDunzl

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We get dig into the noise floor using FFT to below -160 dB easily.

Oh, well, as is usual, I stand corrected!

If that includes -162dB then that's the difference between your favorite opera singer singing to you from a meter and from 83,399 miles/134,218km.
 

amirm

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If that includes -162dB then that's the difference between your favorite opera singer singing to you from a meter and from 83,399 miles/134,218km.
In other words, when you and Sal flush your toilets, it impacts my measurements! So please hold it during testing of Steve's device....
 
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So how is that not tested with an AP? (I assume you're aware that the "transients" are bandwidth limited).

It would be, assuming the stimulus is appropriate and we are looking in the right places.

Most modern preamps and amps have steady-state B/W of ~100KHz or higher. The transient capability of these can be even higher.

With digital, this transient power is driving parts that are switching in MHz with GHz risetimes. The regulators must be must faster than those used for analog.

Steve N.
 

SIY

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The analog output of a DAC is bandwidth limited. I have trouble believing you don't understand that.
 

SIY

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BTW, two graphs of spectra of a transient-laden signal (a square wave) passing through the AP, one at high level, one at low level. Apparently it passes Steve's definition of "dynamic response."
FFT Spectrum_ 1kHz Square Wave.png
FFT Spectrum_ 1kHz Square Wave 10mV.PNG
 

garbulky

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And don't switch on any lights either. The AC transient might affect the AP system.
I hope we won't be kept in the dark with these upcoming measurements ;) . Steve, I am a subjectivist. This forum tends to be objectivist. I'm just telling you that you're not going to be happy with whatever review is upcoming. It'll probably be compared to some $40 convertor or some computers inbuilt motherboard audio and shown that the $40 converter was identical. Just letting you know what you are getting into.
 
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I hope we won't be kept in the dark with these upcoming measurements ;) . Steve, I am a subjectivist. This forum tends to be objectivist. I'm just telling you that you're not going to be happy with whatever review is upcoming. It'll probably be compared to some $40 convertor or some computers inbuilt motherboard audio and shown that the $40 converter was identical. Just letting you know what you are getting into.

I guess I'm willing to take the risk. It's not going to affect my future anyway. I'm primarily doing this because a customer requested it.

Steve N.
 
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The analog output of a DAC is bandwidth limited. I have trouble believing you don't understand that.

Then don't believe it. I don't believe it either. I never said it wasn't.

Transient capability of the digital part of the DAC has nothing to do with this. The power delivery must support di/dt in the 1amp/usec range in order to not result in distortion in the analog output.
 

SIY

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I never said it wasn't.

But then you started talking about signals that weren't bandwidth limited. ("Most modern preamps and amps have steady-state B/W of ~100KHz or higher. ") So you'll pardon my continuing confusion. Which is it?

The power delivery must support di/dt in the 1amp/usec range in order to not result in distortion in the analog output.

The power delivery of what, specifically? And do you have measurements of the analog output of an engineered DAC which shows this claimed distortion?
 
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But then you started talking about signals that weren't bandwidth limited. ("Most modern preamps and amps have steady-state B/W of ~100KHz or higher. ") So you'll pardon my continuing confusion. Which is it?

100KHz or even 1Mhz is bandwidth limited. Are you talking about audio range B/W limited?

The power delivery of what, specifically? And do you have measurements of the analog output of an engineered DAC which shows this claimed distortion?

Power delivery to the D/A chip, the oscillators, the dividers, the registers, the selectors, the buffers. All of the stuff that makes up a D/A except for the
I/V stage, gain stage, filtering stage and output stage. (I do all of these in one stage BTW)

I have better things to do.

Steve N.
 

SIY

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100KHz or even 1Mhz is bandwidth limited. Are you talking about audio range B/W limited?

Yes, that's what the output of a DAC (as well as the signals it handles) is bandwidth limited to.

So, please allow me to ask again- do you have measurements of the analog output of an engineered DAC which shows the claimed distortion from "power delivery?"
 

bunkbail

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IIRC Amir likes the Audiophilleo and this one costs in the same ballpark. Couldn't be that bad, no?
 

amirm

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IIRC Amir likes the Audiophilleo and this one costs in the same ballpark. Couldn't be that bad, no?
I liked the Audiophilleo a few years ago when such interfaces were a novelty and hence expensive. Today $50 units perform excellently so the bar is quite high for higher performance ones.
 

Sir Sanders Zingmore

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1. The measurements show no effect at all

This depends on the measurement method. If only using a DAC to look at jitter, then he is using the wrong DAC. I requested that he use a DAC with resampling on the inputs and one without. I would like to see measurements with and without a DAC.

The other issue is relative scale of the jitter. If one believes that very small differences in jitter are inaudible, then the wrong conclusion may be reached. Like I said previously, a small change in jitter, from 22psec to 7psec was immediately obvious to me using my system and in my measurements. If the playback system used is not resolving enough or the noise level too high, then these differences may not be audible.

2. Your device degrades the measurements.

That would be a shocker. Given that this is my most popular product in 22 years and I have never had ANY negative review, I would have to blame the measurement system or techniques for not correlating to the audio result. My re-clocker outputs very fast edges, around 400 psec. This is why I usually insist on using my 16GHz aerospace quality silver cable from the output to the termination. If the measurement system cannot properly terminate to a signal this fast, it may cause problems in the measurement. The AP system is the world standard, so I believe this is unlikely.

3. Your device improves the measurements.

I would expect this, although I am frankly dubious about the measurement technique. I did notice that my measurements on the iFi SPDIF iPurifier correlate pretty closely with Amir's, so that is reassuring:

https://www.audiocircle.com/index.php?topic=157348.20

Steve N.

Good onya, sounds like you have all your bets hedged.
 
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