DVD players and jitter

[Andrew Pratt]

I came across the HomeCinemaChoice web site that lists the jitter measurements for audio performance on the bench tests of european DVD players. From looking though the list at models that appear similar to ours I get a very wide range of values ...

Sony 7700 - 189 ps
Sony 9000ES - 200 ps
Sony 900V (SACD capable) - 174 ps
Sony 300 - 227 ps

Technics A10 (DVD-A capable) - 2885 ps

Toshiba 9000 219 ps
Toshiba 3109 216 ps

Panasonic RV31 3971 ps

Denon 3300 (DVD-A capable) 621 ps

JVC (DVD capable) 301 ps

Pioneer 37A (DVD-A capable) 1024 ps

As you can see there's a huge variation in these values and from their site they claim

Digital deviation

Although sound quality is influenced by many different parameters, audio jitter leads to a lack of musicality or a softening of the bass amongst other things.

180ps or less: Excellent (audiophile CD standards)

180ps to 250ps: Very good

250ps to 350ps: Good

350ps to 500ps: Average

500ps or more: Below average

2,000ps or more: Terrible

Also I read a review on the Camelot 5.1 dejitter device. It said that it made a huge difference on the Toshiba 9200 and a cheap Panasonic DVD player but that there was virtually no difference when it was tried with a Sony 7700. So does all this point to some strong correlation between low jitter values and higher sound quality esp when used as a transport?

[Andrew Pratt]

articles on Jitter

http://www.jitter.de/english/what.html

http://www.jitter.de/english/soundfr.html

[JonMarsh]

It's very much a factor, Andrew. But one of several. You've hit on one of HT's dirty little secrets, that because of poor PLL clock design, a lot of DVD players are pretty terrible CD players. Of the first generation, the Sony DVPS7000 was about 220 ps if I remember correctly, and the nearest competitors were ten times higher; most were 100 times higher!

Now, one other point- jitter as a single rms number can be a bit misleading; there is signal correlated jitter and non-correlated jitter. And the standard test method may not "exercise" the worst behavior of a typical player. Furthermore, the design of the DAC's, whether they use a packet based charge architecture (as many Sony 1 bit SACD DAC's do, and most of the newer Crystal DAC's), or simply control the transfered charge by the time duration (not so good) is a big factor- then there's the reconstruction filter, and the output buffer.

Last, the other three most important things are power supply, power supply, and power supply!

Then, the question which follows, is what DAC to use? (for CD, I think I've solved that problem with the MP DAC kit I've built- we'll see what kind of second opinion we get when ThomasW get's the one I'm building for him now).

I still haven't had time to go through my closet (for the volume control) but promise to do that in the next couple of days. I have a preamp I started years ago and never finished; which I know has one of these. But I think I have a couple more in the box. There are linear travel sliders purchased originally when I was designing and building some custom pro sound stuff, including mixers; the Duncan conductive plastic units were pretty hot stuff in the sevenities; the dual slider was a C note in 1977.

Regards,

Jon




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[Kevin P]

Sony 7700 - 189 ps
Toshiba 9000 219 ps
Panasonic RV31 3971 ps
...
(re: Camelot 5.1) It said that it made a huge difference on the Toshiba 9200 and a cheap Panasonic DVD player but that there was virtually no difference when it was tried with a Sony 7700.

I'm surprised the Camelot would have made a big difference on the Toshiba, since the 9000 has such a low jitter value. Unless for some strange reason the 9200 has more jitter than the 9000?

In any case, it sounds like the Sony 7700 you bought will trounce the Panny you had before as a transport!

And it also looks like I done good with my Sony 9000ES. I wonder if an external DAC or receiver can add jitter, because I found the sound quality from the analog outputs on my 9000ES (bypassing the digital stages in my receiver) to be noticeably cleaner than when I fed the PCM bitstream via coax into my receiver and had it do the decoding. Of course, there are many more variables affecting sound quality/DAC quality besides jitter.

KJP




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[Andrew Pratt]

In any case, it sounds like the Sony 7700 you bought will trounce the Panny you had before as a transport!

Now you know why I wanted the 7700

As far as your 9000 I'd expect differences in sound b/t it and passing a digital signal to the receiver to be mainly due to the different DAC's but rememeber these values listed are for the jitter from the digital outs...we have no idea what the jitter is on the internal DAC's....one would hope it would also be very low (though I think that's the biggest argument for not using an external DAC ie timing issues)

Here's the review of the Camelot that mentions the 9100 and the 7700

http://www.dvdfile.com/tech/review/processors/dragon.html

[Andrew Pratt]

Interestingly from Stereophile the Sony SCD-XA777ES SACD player scored 171 ps and the Pioneer DV-AX10 SACD/DVD-A/CD player scored a low 142!

[George Bellefontaine]

Nice to know I made the right purchase in the 7700 .




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