Educate me about Jitter

all us longtime guitar players have the cursed tinnitus. I have it raging in both ears. All the time. Or usually.

This is why audiophile quality means nothing to me really. I'm glad I can still hear at all. Good enough is more or less the stereo sound I get.

 

Well sorted indeed!

 

Sorry, my recollection was a bit murky. Just checked the exact quote from August 2009 HiFi News review of the Rotel RCD-1570 states, "Jitter is very high at >2000psec of supply-related effects."

 

Here are questions I think everyone should answer for themselves on this topic if they want to feel satisfied with their position:

Is a global number for jitter important? What global number does one use for some frequency distribution? Does the spectrum of jitter matter? Does any of those earlier answers change if the jitter spectrum is correlated to the musical content or not?

 

John Atkinson over at Stereophile would always test hardware for jitter with his special measuring equipment and the best stuff would usually have much lower jitter than that. There were always exceptions of course and he made allowances for high jitter in certain cases.

 

There's something I've been wondering for some time. I have a Pioneer SC LX-76 A/V receiver from 2012 (sold in the US with the Elite badge) that can play WAV, FLAC and DSD (amonth others) via its USB input. I have my Hi Res music on a Sold State Disc, so it's flash memory, no physical parts moving, and another SSD for my CDs ripped to FLAC with dBpoweramp using Accuraterip. I have all my CDs ripped to ISO and its tracks extracted to DSF files that are stored on the first SSD. I listen to most of my digital music from those SSDs connected to the USB input of my A/V receiver. Playing this way we can rule out reading jitter, no moving parts reading the data. All PCM, either red book or Hi Res are on FLAC format so what goes from the SSD to the USB input on the receiver is not actual PCM data but a bitstream that allows inside the receiver to reconstruct the original PCM data, but induced jitter is also eliminated. I don't think my digital music playing suffers of many jitter, but I may be wrong...

 

I'd be interested to know his chronological testing methodology. If he values low jitter values that much and he measures them before writing down all his thoughts on the CD player's performance, it could color his conclusions.

 

Stereophile reviewers do the subjective listening review first. Then send the gear to John Atkinson who does the measurements. The subjective reviewers don't know the measurements of the gear till after they've written their subjective part of the review.

 

1. Jitter is never eliminated. It can only be minimized. There are posters in this thread who have said otherwise, but they have NEVER cited an authoritative source, only their uninformed personal opinions. Minimizing jitter improves audio performance, and like most things that improve audio performance, it costs money to reduce jitter.

2. The simple answer to your question is that after the data is converted from FLAC to PCM it is reclocked by a clock chip in the DAC section of your Pioneer. Clock chips come in a great variety of qualities so the reclocking will result in more or less jitter depending upon the quality of the clock and the associated circuitry.

3. The more complicated answer to our question is that SSD or not, the data and the clocking never enter the Pioneer's DAC in "perfect" shape, SSD notwithstanding. See the video I posted above (p. 2) on explaining the data signal and the clocking.

 

According to what you say, and I don't doubt this to be true, we could enter again on the matter of "do CD transports have a sound?" and get a definitive "NO" as an answer because if data is read right by the CD transport, and if its output is jittery it will get reclocked by the DAC and its clock and associated circuitry.
Regarding your point #3, what do you understand as "the data and the clocking never enter the Pioneer's DAC in "perfect" shape"?

 

The problem is that if the data does not come in undistorted and relatively jitter free, the DAC has to work harder to fix and reclock it, and that leads to distortion.

As for the date and clocking not coming in in perfect shape, I wold refer you again to the video I posted ot page 2, at #43. In it both of these issues are explained very clearly, certainly better than I can explain it. Have you watched the video?

 

phase noise

 

I knew if I stuck with this thread long enough there would homework and maybe a test.

 

I did watched the video, I found it very informative, thanks for sharing it. My point is,if date is going to get into the D/A converter with some kind of distorsion there has to be good ways, average ways and bad ways to get the original data into the D/A converter. I think the way I suggest, data stored as lossless compression on a Solid State Disc which gets into the receiver that plays it itself, and as I use FLAC, a lossless compression, the original PCM data is reconstructed inside the receiver itself, so no CD reading related jitter, no bus, either SPDIF, TosLink or HDMI, jitter related, only PCM reconstructed right before D/A conversion. This way may have its issues, all of them have them, perfection only exists in a perfect world.

 

Since I got jriver and a dac using asio my cds ripped lossless sound better then any vinyl I ever had.
Now it’s all about the mastering.
Now I use qobuz hires which sounds amazing on my system

 

How does a DAC "working harder" cause distortion? Distortion can only arise if there is missing data -- or the data being received is so faulty that the CIRC error correction can't recover it -- and the DAC is using interpolation to fill in the gaps (such as on a scratched CD).

And if faulty digital data somehow fails to be caught by the error correction is passed through to your speakers, it won't sound like subtle analog-style distortion -- it will sound like loud sudden bursts of white noise.

 

Be sure to insist on authoritative sources. For instance, so far I'm gathering the Audio Adviser catalog is an authoritative source for matters of jitter.

 

The only way you know jitter is a problem in your system is when you minimalize it . The same goes for clean AC current .