Ayre CX7e vs. Meridain G08

Hello Zaikesman,

Sorry you choose not to believe me. Here is proof of what I am talking about:

Go to the bottom of Stereophile's review of the dCS Verona master clock:

http://stereophile.com/digitalprocessors/305dcs/index4.html

and you will see the following footnote:

"Footnote 1: For reasons unknown, all these measured jitter levels are about twice what I measured for the Elgar and Verdi two years ago. They should therefore be considered as relative rather than absolute values."

Now I don't know about you, but I consider a 100% variation in test results over a two-year span to be problematic at best. I did contact him about this several months ago, but with no substantive reply to date. I suspect that he is pretty busy and that this is not high on his priority list.

Charles Hansen
Ayre Acoustics, Inc.

I went back and read the CX7(not the CX7e) review from the May 2003 Stereophile. JA stated the CX7 had some of the lowest jitter(159 picoseconds of peak to peak) of any player he had measured.
The higher levels of jitter seemed to start showing up about 2 years ago or less. It would be interesting to re-measure that same player now.

Mr. Hansen: Thanks for your expanded comments and the link, I did not recall that JA admitted to some mystification about his results. I certainly agree that these jitter tests seem to be exquisitely sensitive and should probably be taken at something less than strictly face value. But if you reread my post, I think you'll see that nothing I said was in disbelief of your statements.

Based on my own brief measurements using the Audio Precision 2722 analyzer (this is a $27,000 piece of test equipment with an FFT noise floor at almost -140 dB), I think that this particular test protocol is flawed. I suspect that for well-designed digital audio equipment, the test tends to measure the noise floor of the analyzer/computer rather than the device under test.

I think Bigtee is right that the higher jitter levels in JA's test reports started showing up around two years ago. Maybe the increased jitter measurements in JA's test resulted from some change to his computer, perhaps the installation of a Wi-Fi card.