RF Attenuators = Jitter Reducers

Do you have a SPDIF transformer in your Digital Device

  • Yes

    Votes: 40 71.4%
  • No

    Votes: 16 28.6%

  • Total voters
    56
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luvdunhill

Member
2006-07-09 6:59 pm
Not expensive enough to get Audiophile Approval

:(

Does this qualify, 'cause that's the best I can do.

Krell%20002.jpg
 

jkeny

Banned
2007-02-06 12:43 am
Dublin
Ok, I see the tone of this has now turned derisive while I was asleep. I was under the impression that you, SY, wanted to do a fair test? I offered you a list of DACs that have been shown in the past to allow these differences to be heard. If you don't like or have access to any of these DACs, I offered to provide you with a longer list. Are you being genuine in this whole process? If you consider this an experiment, then why would you want to change the parameters of the past successful experiments?

Janneman, nothing personal but your post reveals a lot about your lack of understanding about repeating scientific tests & keeping as many parameters fixed as possible. There are some DACs that have been used which did not reveal any differences to the user. I personally haven't heard these but I trust the reports from my users & refunded them the money. In the past, I offered you the unit to test, as you were in Europe, but you refused. Please don't try to tell how to conduct this test - if you want to do a your own test, the offer still stands

Sy, again, being derisive about the DACs in the list does not auger well for your impartiality in this. I was hoping for more from you!

How about you show the analogue out tests from two different CDPs with known & published differences in jitter & you verify that your DAC & measurement technique is up to the job? I thought that this would be the first step in the whole process, to be honest, & is something I asked for way back on another thread where I was accused of "not being interested in proof at all". I believe the ball is in your court to show that you can do this test in a fair & reasonable manner with equipment that is shown to be capable.
 
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No, Sy, you have not asked about the suggested DACs or indeed any other DACS which may be appropriate. Why? Why are you not interested in conducting this experiment with proven DACs. If you insist on using your own DACs then I suggested that you demonstrate the capability of your equipment to reveal in the analogue waveforms jitter differences between two known pieces of equipment. You have not answered this.

I have done everything that I can to make this a test that is of some relevance, providing the DUTs, providing a list of DACs, suggesting ways that this test has some validity. Please try to make this test of some value!

The ball is in your court - is this just going to be a worthless test on equipment of your choice which you will not validate is capable of performing the test & just an attempt to knock subjectivist claims. Are you serious about doing a test that is seen to be fair?
 
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SY

diyAudio Moderator Emeritus
2002-10-24 10:19 pm
Chicagoland
www.SYclotron.com
I guess I haven't heard why my DACs are not appropriate. What do you see in their measured results which leads you to believe that they can't show distortion, spectral broadening, or noise reduction?

I'm certainly willing to spend my weekend at concerts instead of in my cramped lab doing you a favor. My current favorite female singer is doing a show at Flipnotics tomorrow, and Red Young always puts on an excellent show at the Elephant Room. Just say the word and I'll pack it up untested and return it.
 
We won't need to go through this needless back & forth tediousness about DACs if you just show an actual test using your equipment which will demonstrate that it shows jitter artefacts on the analogue waveform & can differentiate between two different levels of jitter on these plots. It really is a simple request & a trivial thing to do by your own accounts. Please prove your equipment!
 

SY

diyAudio Moderator Emeritus
2002-10-24 10:19 pm
Chicagoland
www.SYclotron.com
Any DAC shows jitter artifacts in its spectrum IF the jitter affects the conversion. If it doesn't, then it won't. Your premise is that jitter on the spdif line manifests itself in the DAC output (since you're claiming sonic differences). That's the premise under test here. Demanding that the premise be proved in advance in order to judge test validity makes no sense- either your unit causes the DAC output to be cleaner or it doesn't.

The DACs used here are demonstrably capable of resolving extremely low levels of noise and distortion as evidenced by the presented spectra. It IS possible (I don't know) that your premise is incorrect and that DACs really don't care much about SPDIF jitter, and an open-minded approach will accept that this is a possible outcome. Not good for sales, perhaps, but I'm not in the business of selling anything. The results will be what the results will be- I have no axe to grind one way or the other.
 
I guess I haven't heard why my DACs are not appropriate.

John has explained why they're inappropriate for listening. That's because so far there are no reports of differences being heard through them. So why would you wish to change the parameters of the previously successful experiments?

I'm certainly willing to spend my weekend at concerts instead of in my cramped lab doing you a favor.

I can only suggest that if this 'favour' isn't win-win then do not bother. Self-sacrifice just makes for martyrs.
 

jkeny

Banned
2007-02-06 12:43 am
Dublin
No I disagree with you - any DAC will not show changes in jitter on the analogue out waveform because some DAC implementations have high intrinsic jitter, use an ASRC, have high inherent noise, etc & the effects are masked. I'm telling you that I don't believe your DAC is capable of doing what you say, yet you insist on using it. SO the onus is on you to prove that it lives up to your claims, simple!

You have already stated that you did not find the attenuators effect on the SPDIF waveform to be anything like the posted scope shots. Would you post your shots, test set-up & analysis, please?

If you cannot prove your equipment is capable of differentiating two different levels of jitter at the analogue out then how can you claim that your test is anything but a useless exercise? If the result is negative, it proves what, exactly?

I find it amusing & somewhat ironic that you use your equipment as test equipment but have no wish to show it's capability or demonstrate it's usefulness for this test! You are simply relying on generalised statements about technical capabilities & we are to accept these?
 
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luvdunhill

Member
2006-07-09 6:59 pm
do you really own this or are you just taking the ****?

I own it. It was the first piece of (commercial) gear that I sat down with that really sounded better than any DIY (DAC) I threw at it. I suppose there's a cost of entry to get to this level, but it has deftly slain any and all competition.

jkeny:

If the DACs in your list have this intrinsic "problem" that is solved by this gizmo, then doesn't it stand to reason that they are poor implementations? Wouldn't a DAC that isn't affected by the addition of this gizmo be "better" by some definition of better, even if that definition is "better engineered"?
 

jkeny

Banned
2007-02-06 12:43 am
Dublin
I own it. It was the first piece of (commercial) gear that I sat down with that really sounded better than any DIY (DAC) I threw at it. I suppose there's a cost of entry to get to this level, but it has deftly slain any and all competition.

jkeny:

If the DACs in your list have this intrinsic "problem" that is solved by this gizmo, then doesn't it stand to reason that they are poor implementations? Wouldn't a DAC that isn't affected by the addition of this gizmo be "better" by some definition of better, even if that definition is "better engineered"?

What I said was that some DACs mask low level jitter sources & so the sonic benefits of such sources will not be heard i.e will not be seen on the anlogue output waveform. So testing & listening will reveal nothing. Nothing to do with my gizmo solving a DACs problem!
 

luvdunhill

Member
2006-07-09 6:59 pm
What I said was that some DACs mask low level jitter sources & so the sonic benefits of such sources will not be heard i.e will not be seen on the anlogue output waveform. So testing & listening will reveal nothing. Nothing to do with my gizmo solving a DACs problem!

:confused:

I guess this where I'm confused. Anyways, perhaps I will head over to SY's place and make sure he doesn't slip a Bybee in there and rig the results :cool:
 

jkeny

Banned
2007-02-06 12:43 am
Dublin
The idea broached that a unit which is incompetently designed so that spdif jitter upsets its operation is somehow better astounds me.
Who said that?

If you want to hear what John Westlake & others have to say about the CS8420 chip used in your DCX then go here http://www.diyaudio.com/forums/digital-source/47943-cs8420-really-bad.html#post535481

"Is the CS8420 really that bad"

YES - Just Terrible! Completely destroys the audio performance / sound stage.

Also the PLL on the integral SPDIF Rx has a Bi-Modal phase noise distribution. This means instead of having a single clean narrow clock carrier (single frequency). There are two carriers (two frequencies) close together – poor PLL design.

On a spectrum analyzer sweep, the profile of this distribution depicts the wrong kind silicon……. (At least in this instants)

This is really tedious having to prove to you that your DAC is crap - if you believe it isn't then do the test I asked & prove it is capable. All you've done to now is talk about it - why not test it?
 
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