Sy,
I'm sorry that I have to insist on these things. But look, really, this is nothing special, just everyday normal electronic basics applied. That You have less reflections with a unit with considerably less rising time, it's really electronic's 101.
Then, You could ask, why should I not just use the (much) slower unit?
The response is in the Hawksford article, very clearly explained. You get much higher Inter-symbol interference jitter, or "Data Dependent jitter" or "Deterministic jitter", different names, the same story always.
I'm sorry that I have to insist on these things. But look, really, this is nothing special, just everyday normal electronic basics applied. That You have less reflections with a unit with considerably less rising time, it's really electronic's 101.
Then, You could ask, why should I not just use the (much) slower unit?
The response is in the Hawksford article, very clearly explained. You get much higher Inter-symbol interference jitter, or "Data Dependent jitter" or "Deterministic jitter", different names, the same story always.
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I think you need to check your instrumentation if this measures the same as the modified Hiface (i.e. sounds the same). Can you run a CDP through your system & show the analogue out waveform or do you have any control?
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Maybe because you can't see jitter with your test set-up - it is normal in any experiment to do a control to prove your equipment is capable
Hello
What equipments did you used for your jitter test ?
A jitter test should'nt be done with signals of 11025Hz + 229.6875Hz ?
Thank
Bye
Gaetan
I'm not measuring jitter. I'm measuring analog signals.
Listen, I am in sympathy with you. If I were selling a gadget for $500 that works perfectly well, but gives end results that are excellent but no better than a product that sells for 20 times less, I'd be unhappy. But the Hiface can do one thing the Chinese unit can't: 192k. So be happy with that.
Sy,
I don't know about Your measurements - one reason can be that ~30db dynamic range difference, between Your card and the EMU1616 shown here.
With the EMU, i can see the difference between two (not very bad, re-clocked, fixed XO driven CD players) by looking at the analog output. A very bad high jitter unit had been seen showing just that, high jitter in my tests.
So really, there are a lot of points to clear up here.
Not talking about the fact, that your cards are using jitter supression +are low resolution in this respect, and You are asking me why You don't see a jitter effect which should be present on the SPDIF line?
If You ask me, it is there, high time. I am saying this, because I had seen this.
The high price scope with the jitter analysis package, Measuring Directly on the SPDIF Line, had shown ~300psec rms jitter (sorry, as told already, only memory) with the EMU soundcard - slow rise time SPDIF output, like Your chinese unit, or slower. And this was a very high content Data Dependent jitter.
The HiFace unit measured in the same way and shown here does 37psec rms jitter, and is having a much much lower Data Dependent jitter content, then the EMU.
I don't know about Your measurements - one reason can be that ~30db dynamic range difference, between Your card and the EMU1616 shown here.
With the EMU, i can see the difference between two (not very bad, re-clocked, fixed XO driven CD players) by looking at the analog output. A very bad high jitter unit had been seen showing just that, high jitter in my tests.
So really, there are a lot of points to clear up here.
Not talking about the fact, that your cards are using jitter supression +are low resolution in this respect, and You are asking me why You don't see a jitter effect which should be present on the SPDIF line?
If You ask me, it is there, high time. I am saying this, because I had seen this.
The high price scope with the jitter analysis package, Measuring Directly on the SPDIF Line, had shown ~300psec rms jitter (sorry, as told already, only memory) with the EMU soundcard - slow rise time SPDIF output, like Your chinese unit, or slower. And this was a very high content Data Dependent jitter.
The HiFace unit measured in the same way and shown here does 37psec rms jitter, and is having a much much lower Data Dependent jitter content, then the EMU.
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Well, again, if the levels of jitter in the spdif stream that you're talking about affect the D->A transformation, one would see sidebands. They're not there, with a baseline resolution FAR below any plausible audible threshold.
If you want to worry about stuff at -150dB (if it even exists), you're free to do so, and I'll freely admit I'm not looking down that low.
If you want to worry about stuff at -150dB (if it even exists), you're free to do so, and I'll freely admit I'm not looking down that low.
Sy,
In the measurements of J.Atkinson, shown in the link by Thorsten, there are a lot of sidebands, different with each unit, and they are not very high jitter units, except for the Bel Canto.
He has done exactly the same what You are doing here.
In the measurements of J.Atkinson, shown in the link by Thorsten, there are a lot of sidebands, different with each unit, and they are not very high jitter units, except for the Bel Canto.
He has done exactly the same what You are doing here.
That signal is the generally accepted test signal applied in jitter tests, not by accident. Thought up by Julian Dunn, not casual selection.
Also I had been using the same signal.
Also I had been using the same signal.
Your supposedly measuring the spuriae of jitter on the analogue waveform but you have not shown that your system is capable of doing this
Please don't be so condescending - I would love to believe that you have genuinely tried to do a fair & equitable test but I'm afraid I'm led to the conclusion that you have been less than an unbiased agent in all this.
You refuse to show a mis-terminated line & it's results which is the purpose of the attenuators - why not?.
You have not tried to use the test configuration already reported for the attenuators.
As regards the low-rent USB-SPDIF VS Hiface; you have not shown that your system is capable of showing jitter by actually showing jitter on a plot that you have made with the same equipment in the same configuration.
I asked you about your listening results but you have been evasive as usual - anyway I know what your listening result will be as you have already stated that anything other than what the measurements show is Boogaboo!
If your contention is that this $30 USb transport sounds the same as my Hiface, then your credibility is strained, your equipment is incapable, you are deaf, or disingenuous ......
If you are now finished with the Hiface & attenuators (you have had your little joke) then kindly mail these on to someone else whom I will nominate & of course I will pay shipping.
Somebody in the US George, Pano would you be interested? If you believe that you can give an unbiased opinion & tests then I'm willing to do so. Anybody else want to try this out?
This has been very revealing, SY to everybody 😀
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Sy,
You are looking at units which are only different in jitter. Then what is the scope of all this?
You are looking at units which are only different in jitter. Then what is the scope of all this?
To see if the modified Hiface, when connected to a DAC and having the attenuators in the spdif line, causes the DAC to output an analog signal which is any different than a reference unit when fed by normal signals (i.e., ones that come from normal digital sources). I didn't have an unmodified Hiface, so I went to a more extreme direction and used the cheapest unit I could find as the reference.
Sy,
I think it's fair and I think also that we could stop here. I see Your point, and I really feel that in this hobby everybody has the absolute right to form an opinion for himself.
Though I can not help but insist on this point: If it is claimed that a "product" is modified/ bettered in a specific technical parameter, then to certify the result, one should do adequate, specific testing aimed at that specific parameter. This was / is not your original intention, and that's all OK for me.
One last thing: I can't stand the feeling that You "smell" something tricky with the Hiface/attenuator waveform shots from my side. A little, easy test came in mind:
To see the real waveform of the Hiface unit, please just use an USB extender cable, and a BNC-RCA (or BNC-BNC) "I" converter, so as to be able to directly connect the Hiface to the scope input. The input should use the internal 50ohm termination. If You would insert also an attenuator, that could just help even more, but I think already the direct connection in itself will clear up things greatly.
This way You should get a ~reflection-free correct waveform shot.
Ciao, George
I think it's fair and I think also that we could stop here. I see Your point, and I really feel that in this hobby everybody has the absolute right to form an opinion for himself.
Though I can not help but insist on this point: If it is claimed that a "product" is modified/ bettered in a specific technical parameter, then to certify the result, one should do adequate, specific testing aimed at that specific parameter. This was / is not your original intention, and that's all OK for me.
One last thing: I can't stand the feeling that You "smell" something tricky with the Hiface/attenuator waveform shots from my side. A little, easy test came in mind:
To see the real waveform of the Hiface unit, please just use an USB extender cable, and a BNC-RCA (or BNC-BNC) "I" converter, so as to be able to directly connect the Hiface to the scope input. The input should use the internal 50ohm termination. If You would insert also an attenuator, that could just help even more, but I think already the direct connection in itself will clear up things greatly.
This way You should get a ~reflection-free correct waveform shot.
Ciao, George
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