[AdamZuf]

1.what exactly is jitter? (i know that, just would be nice to have an informative answer)

2.why portable devices with digital output are more likely to have jitter problems then home devices?

3.what part in the device determines its jitter? (or, where is the jitter actually created)

4.how does high jitter hurt quality? how does it sound?

5.in what units does the jitter measured? ("unit" such as centimeters, mA etc..)

6.what jitter specs should an audiophile look for when he buys a device with digital out? (what is bad,ok,good,excelent)

7.does digital cables affect jitter level?

8.which digital method is prefered, coaxial / optical ?

 

[markl]

I'll try a few:

1. It's digital "distortion". I'd take a look at the web site of any of the "jitter buster" type products for in-depth explanation.

2. PCDPs are cheap and compact. Better and better CDPs are made with better parts that suffer less from jitter.

6. manufacturers do not list "jitter" in their specs. many don't believe there is such a thing as jitter anyway. Jitter is not without controversy. There are "flat earthers" that insist that all CDPs from the lowliest Rat Shack PCDP to the most outrageous Linn $20K CDP are identical in sound quality. Obviously they are wrong.

7. Another controversial topic. I can hear differnces in digital cables almost as much as any cable swap. Whether or not this is related to jitter, who knows. Some cable manufacturers do promise reduction of jitter.

8. COAX! optical is not nearly as good.

Mark

 

[JohnR]

some info

http://www.geocities.com/jonrisch/jitter.htm

 

[AdamZuf]

mark,
you say that you hear the difference in digital cables.
if so,it's very likely that the sources' coax out sockets quality also affects quality.
(or something else that i do not know and understand yet

)

did you try to compare 2 kinds of CDP's with coax out in a DAC setup, with same music, same cables, same everything ?

 

[markl]

Adam,
I used to own a Sony SCD-C333ES SACD player that I had modified by Modwright. One of the mods performed was to upgrade the digital output section. One of the mods was to replace the standard digital connection with a really beefy one from Cardas that was pretty sweet, plus other mods to digital signal path.

I compared the digital out of the modified Sony player to that of my current source, a Kenwood Sovereign 5700 DVD-Audio player. These were hooked up to my Denon AVR 5800 receiver (top-of-the-line with outstanding digital section). I used the outstanding headphone jack on the Denon to compare via my Sony MDR-R10s. Both players were equivalent in terms of price ($1200, although the Sony also had $600-$800 worth of aftermarket mods done to it). There was no doubt whatsoever, that the Sonys modified digital output was superior to the Kenwood's. The difference was of the magnitude that anyone could tell (through my R10s at least).

Yes, I believe that the quality of the transport makes a HUGE difference in sound quality, with jitter being one of the factors that makes that difference. Do a search on "transports" and you'll come across a thread that goes into detail on this issue.

mark

 

[jpelg]

Quote:

did you try to compare 2 kinds of CDP's with coax out in a DAC setup, with same music, same cables, same everything?

I've compared using my PCDP w/optical out to a few, low-end (< US$400) full-sized players. I compared using the same optical cable on both, and compared using optical with the portable against using an inexpensive (<US$50) coax cable on the full-sized players. Same headphones (usually Ety ER4S's), same music (a variety of redbook CD's) I hear no difference.

Possible reasons are:

1. There truly is no difference. It's all marketing BS.
2. The quality of the players and the cables are all so low that it doesn't make a difference at this level. If so, this begs the question, at what $$ level does it become relevant?
3. My DAC compensates for any shortcomings of the transport & cables, giving the same output from anything fed to it. If so, then isn't this the best way to combat "jitter"?
4. My ears are bad. If so, then I can stop now, and can save alot of cashola.

Take your pick (or feel free to insert your own possibilities).

/edit formatting errors

 

[AdamZuf]

mark, you're out of the talks' price range

it probably happens a lot to you

maybe DIY modifications to more simple DVD players can make a cheap solution with great improvement ?
anybody got links?

 

[Dusty Chalk]

There was a recent thread on jitter on the ls35a forum in yahoogroups...let's see if I can find it...ah, here it is. (Not sure if that link is going to work if you're not already a member of that group, but there's an extensive discussion with lots of informative links, I'm not reiterating it all. So, those of you who are annoyed by links to other sites, don't click on it.)

 

[Wodgy]

Quote:

Originally posted by AdamZuf 8.which digital method is prefered, coaxial / optical ?

If you're using a computer as a source, optical is often preferred because it keeps the computer's (very dirty) ground separate from your DAC's ground. With audio components, however, most people prefer coax.

 

[aos]

Uhm, jitter isn't controversial per se. You'll learn about it at any university if you study electrical engineering. If anyone doesn't believe jitter exists they're probably... well, yeah, flat-Earthers. Should be taken on a space station or something. In this case, taken to introductory Telecommunications course and directed to perform an exercise involving signal to noise ratio in digital circuits and see it for themselves on the oscilloscope.

What you think about is whether jitter is *audible*. That really IS a controversial subject, as the judgement is subjective.

At least some Sony PCDPs do have very high jitter, based on what I heard from someone who has access to the measuring equipment, and also in my experience. Especially with G protection on. It is so high in fact that it can cause problems - some receiver chips (part of DAC) cannot lock onto it.

If you're one of those who can or believe they can hear the difference that jitter makes, there are many things that can be done though many are either in hands of the DAC/CDP designer or are compelx to perform. Modding the player (replacing clock with low jitter one and/or even adding some simple circuitry that further reduces output jitter), trying higher quality cable - if the cable does not have proper impedance, modifying the DAC itself so that the cable sees proper termination, reclocking the signal, asynchronous sample rate conversion, using modern multi-bit sigma-delta converters that are less sensitive to jitter etc.

 

[AdamZuf]

Quote:

Originally posted by aos If you're one of those who can or believe they can hear the difference that jitter makes...

well..i guess that depends on the level of the gear..my gear would be: DT880, EMP, ART DI/O DAC, DH Labs BL-1 cable.
maybe Meiers' Cross-1 added.
i don't want to get into all of the digital mods you talked about, it has to be cheap & not complex, if i make a mod in a relatively cheap device.

Quote:

Originally posted by markl I used to own a Sony SCD-C333ES SACD player that I had modified by Modwright. One of the mods performed was to upgrade the digital output section. One of the mods was to replace the standard digital connection with a really beefy one from Cardas that was pretty sweet, plus other mods to digital signal path.[/B]

mark, did Modwright evaluate the importance of the Cardas output next to the other digital mods in the result?
it seems that just the output replacement is a not a very complex thing to do (or is it?), but getting into the digital section is..
what is the cost of that Cardas output?

BTW,which coaxial cable do you recommend?

 

[blr]

Jitter is put simply a time domain error.
I couldn't find any connection between the jitter as published in reviews and sound quality. I guess most modern players keep it well under control and there should be other sources of distortion that are more audiable. Very high jitter (>1000ps) should be audiable as harshness and lack of detail. Some DACs transport combos are believed to suffer from this. Anyway for a one box player I wouldn't look too carefully into the jitter figures

 

[AdamZuf]

i wonder what Modwright did exactly to marks' SACD player..

jpelg,
i guess it might go to:

"2. The quality of the players and the cables are all so low that it doesn't make a difference at this level. If so, this begs the question, at what $$ level does it become relevant?"

or you chalange markl, and HE is the one that should say:
"4. My ears are bad. If so, then I can stop now, and can save alot of cashola."

mark, you should start to believe in it, and stop spend money on this hobby

 

[jpelg]

Quote:

or you chalange markl

No challenge necessary. I just offered a statement of what my actual experience has been, with my limited hardware, and admittedly limited knowledge, for whatever it was worth. Just becuz it flies someone in the face of the typical audiophile bandwagon, doesn't mean anyone should be offended or "challenged".

I don't doubt anyone who says they hear a difference, especially with better equipment. Just that everyone can, and with all possible hardware. People should listen for themselves before accepting some things that are oft tauted as fact, when they may be more controversial than that.

 

[markl]

Here's what Modwright did in total to my 333ES:
Quote:

Upgrade power supply with Schottky rectifiers and further mods to lower the noise floor Upgrade key analog power supply capacitors to Black Gates Upgrade key digital power supply capacitors to Black Gates and Sanyo OS-CONs Upgrade all op-amps to ultra-fast Linear Tech. Units with current loading mods Upgrade key analog signal path resistors to Vishays and Caddocks Upgrade key analog filter path capacitors to Wima films Upgrade analog coupling caps to Black Gates with Auricap film capacitor bypass caps Add an IEC socket for use with removable power cords Damping mods Here's Modwright's description of the Bybee Filters: WOW! I immediately heard a HUGE improvement in my system. Things were clearer, highs sparkled and bass simply growled. It simply removed a large amount of grunge that I did not realize was blocking the audio signal. For a technical explanation of how they work and what they do, I would recommend going to Bybee's website - www.bybeetech.com. Soundstage, resolution, dynamics were simply ALL improved. I have found nothing but good results with these units and I highly recommend them. Finally, here's an idea of what Modwright did to the digital out (he has removed the 333ES mods from his site, but this is the mod he does to another unit): Transport Upgrade: Upgrade digital out jack to a Cryo treated Cardas RCA, upgrade digital out resistors to precision 1% metal film units, upgrade digital filter caps to Black Gates and hard-wire digital out circuit with Jena Wire.

jpelg has it right. With a sample size of two players, no matter what level they are on, you may not hear a difference, but that doesn't necessarily establish that there are no differences in CDPs as transports. The other factor is that I have no idea really whether the differences I heard were related to jitter at all or just the results of other unknown factors (build quality, etc.). In any case, the difference was major with my sample size of two players.

The other issue is that hearing differences of this level *can be* something that has to be learned. Because I'm so deep into the hobby, I've owned tons of gear over the years, cables, power conditioners etc. So I'm used to the drill of swapping in new components and very aware of the changes they make. Changes that sound major "night-and-day" to me may not be worth while to the next guy.

As in all things audio, YMMV.

Mark