Audio roulette - Are we hostage to clock specs ?

[Nick]

Hi,

Over the last couple of years its been my privileg to listen to some super systems owned by members of the forum and have been on a long personal journey seeking the best sound quality I can get here. In the many trips back and forth listening to systems and swapping components about I started to have the distinct feeling that near identical components, PCs and DACs did not always sound exactly the same ! In particular the level of harshness, bass performance and presence reproduced seemed to vary annoyingly as my system was often the one with the problem haha. I know there are many many variables with computer audio but this experience just kept happening.

From this and generally playing about far too much with PC settings clocks in the audio chain and researching clock gen and other parts of PCs as an idea has solidified.

I have repeatable experimental evidence that 4 oscillators in the audio chain (PC and DAC) directly impact sound quality.

+ Audio bit clock
+ USB receiver clock
+ USB host clock
+ Mobo master clock

+ Plus there are two more that I’v researched and intended to experiment with which I am almost sure will add to this list.

Its been generally accepted, (I bought into this as well) that if you re-clock at the DAC then upstream timing doesn't matter but this is just not born out by experiment. For each of the clocks listed above supply noise, phase noise, and clock speed, are parameters that impact sound quality. Generally it is not hard to improve on the standard x-tal set ups at these locations (exception being the audio clock Peter has in the NOS1a boy that is good !).
So without going into possible reasons / mechanisms that these clocks interact with sound quality (i have lots of ideas) and relying only on subjective observations relating to each of these clocks my thoughs / conclusions are.

1)   Music quality is absolutely hostage to performance  of the oscillators at these locations
2)   More worryingly, I wonder if normal variation between Mobo, USB and other clocks from card to card  or mobo to mobo (even where they are the same product) explains the variations I mentioned above between what should be similar system components.

If the aim is to sweat the last few percent of performance out of a system (and with the NOS1a this is defiantly an objective which is possible) then a holistic approach to manage these oscillators is needed. Otherwise IMHO there is too much of a luck factor that will determining if the sound will “fly” of have frustrating problems.

It’s like resonance / vibration in a vinyl setup.
Stylus tip => cantilever arm => Cartridge body  => Arm resonance => Arm Board  => platter bearing => desk suspension => equipment support . Resonance in any screws up sound. Maybe we shoud be thinking about replay chain oscillators in a similar way ?

Any thoughts ?


Nick.

Ps As I write sat I’m listening to dance music having just tuned the speed of the master clock on my Mobo (yes speed really maters) and the sound is like being in a really good night club.