Femto clocks ,every unit should have one

I agree with most of what Wisnon just said. I wouldn't claim that every chinese CPU clock can beat any femtosecond clock, but maybe some of them.
These canned clock's are usually made with a logic gate as the active element, in a Pierce coupling. Such as the 74HCU04 The equivalent input noise is relatively high. I don't think anyone would use 74HCU04 as a RIAA amplifier?
Noise on the input of the active gate, transfers directly to jitter in the clock signal.
Also the input level is half that of the Vsupply. So half of the noise on the supply rail is transferred to the input. That's why the regulator is of great importance.
Much better is the Colpitts oscillator, built with discrete transistors. Here you can get somewhat better noise (jitter) performance.
I agree with Wisnon also that jitter is not necessarily a make or break factor, the problem is when the music signal is transferred to the clock, over the 5V supply lines. That is going to kill depth perspective, and sound stage. And strangely if you have a jitter instrument, you will find this in many CD players or DAC's. Random jitter is far less intrusive, and like low order distortion in tube amplifiers, it can mask other distortion / jitter.

Wisnon, Drusstheaxe, and Larsclausen, nice of you guys to chime in. :-)
Perspectives other than conventional and unconventional wisdom are most welcome here. It makes my head hurt, trying to get it around all of this but it's most appreciated.

All the best,
Nonoise

ITs very interesting to read these comments on what matters with digital reproduction, but its also very hard for most anyone I would think to get their arms around what works and does not work better in the digital domain. Makes getting ones arms around traditional audio issues like turntable setup and impedance matching seem like childsplay.

Keep it coming though. More information is always better than less.

Wisnon,
I really appreciate your thoughts and perspectives. I have no doubt that jitter has some meaningful effect on performance. It seems however it has become the accepted buzz word and has succumbed to marketing manipulation as the most (only) important digital sonic variable. I still believe fundamental factors such as analog output stage and power supply have a hugh impact on the sound quality. This discussion has become very interesting and educational.
Charles,

I think we should probably all agree that off the shelf, untreated CDs by and large sound thin, unnatural, generic, threadbare, tinny, dull, compressed and papier mâché like.