Jitter and 75ohm cable length

Magfan, I had to send in my unit once for repair about a year or so ago where the transport had problems loading a disk. When I received the unit back they provided a note where they said in addition to the repair they upgraded some power supply caps so the unit, as they say, "reduced the in-your-face presentation" (whatever the heck that is supposed to mean). No mention was made of a firmware upgrade, but I am suspicious they did upgrade the firmware but wanted to keep it low-key. My current version is; 01/069/1.1 is this the latest firmware you are aware of? I have all of the facilities to upgrade but have never received information that one was available. I did call CA and they told me there was only one upgrade since the CDP was released and it as they claimed did nothing to improving the sonic qualities of the unit and was specifically targeted for the Apple AirportExpress claiming the Jitter from it was so severe at times the 840C could not get a lock, so they somehow through the firmware update opened the window and made the unit more forgiving of received data. Is this how you understand the issue? Am I on-base about this or had I been fed a bunch of bunk? Lastly, do you know if the version I have is the latest and if not how do you find it and what is it supposed to improve?? Thanks!
Rpg

CA no longer sends out the file. It was 'zipped' and contained a readme and the installer and some other stuff.
It is on my laptop but I've never mustered the guts to DO it. My laptop is Windows 2000 or ME....dual boot. NOT XP, which is what they recommend.

You have more information than I. If they have only issued one software upgrade, than I've got it. I probably also have the 'old' caps.....

To find out you press some front panel buttons on the player......01/67/1.2 is in my player and found by repeatedly pressing the 'menu' button.
I don't know what the latest version is 'supposed' to be.

And Yes, I think you are on base about the AE jitter issue. The Stereophile test showed it to be awful. The AE is unclocked, as I understand it. I also make sure my computer is doing nothing else when I stream music via iTunes.

"The Stereophile test showed it to be awful."

Not exactly. High jitter appears on analog outputs only. Digital is about 10x better (258ps vs 2400ps) and that's what Stereophile stated:

"The noise floor has dropped by 4–5dB, the word-clock jitter to a respectably low 258ps, which is actually better than the case with the standalone D/A processor driven directly by my PC's S/PDIF output (provided by an RME PCI card).

Considering that the AirPort Express's analog output is basically a freebie function added to a computer Wi-Fi hub, jitter aside, its measured performance is quite good. The beauty of this unassuming component, however, is its S/PDIF data output, which allows the AirPort Express to assume a respectable role in a true high-end audio system."

Kijanki, if one suspects they have a Jitter problem with their system, how might it manifest it's impact on the analog output. I had read an article indicating that high Jitter would make vocals sound overly warm, which actually may be desireable? Is there anything else you can add to the impact of sound reproduction? Thanks!

Rpg

Rpg,

Jitter is basically a noise in time domain. Applied to one frequency it creates sidebands at very low levels. In spite of low levels (less than -65dB) sidebands are audible being not harmonically related to root frequency. Now, take whole bunch of frequencies (music) and you'll get whole bunch of other frequencies at very low level - basically a noise. Amplitude of this noise is straight proportional to amplitude of music and without music (gap) is zero - therefore undetectable.

My first impression of Benchmark DAC1 that suppresses jitter was that sound was too clean (some people call it sterile or analytical). I had impression that some instruments had to be missing from the recording. I also understand that noisier (or distorted) signal sounds more lively the way that distorted guitar sounds more dynamic than clean jazz guitar at the same volume. Other than that sound is on neutral side - I would not attribute any warmth or lack of it to jitter. Imaging is more focused but perhaps a little narrower.

I don't see warmth as desirable quality. Benchmark technical director John Siau said that overly warm gear can negatively affect sound of instruments with complex harmonic structure like piano making it sound almost like out of tune. On the other hand cold sounding (expanded odd harmonics) gear is much worse. I had problem of brightness until I replaced speakers with aluminum dome tweeters. New soft dome Hyperion HPS-938 are wonderful - neutral and never bright on any CD. Sibilants are still very audible but always clean and natural.

I think that main difference between oversampling or upsampling DACs and NOS DACs is not the sampling itself but filtering. Traditional linear filtering adds pre-echo to impulse. Our hearing is very sensitive to it and getting rid of filter altogether (NOS) or using apodizing filter (extending post echo) might be a good thing. Here is some info on the subject:

http://mrapodizer.wordpress.com/2011/08/16/technical-analysis-of-the-meridian-apodizing-filter/