USB processor clock has impact on audio, tested on four different usb boards.
It is only 1.5-3 USD to try, perhaps later some members will confirm my experience. Huge improvement I've recieved on SA9227 usb receiver with independent 45/49 clocks with ES9039q2m in ASYNC mode without MCLK, with swapping 12Mhz processor crystal to cheap normal oscillator. Near the same was on another XMOS boards. This thing don't need and perhaps can't to be measured, it need to listen.
It is only 1.5-3 USD to try, perhaps later some members will confirm my experience. Huge improvement I've recieved on SA9227 usb receiver with independent 45/49 clocks with ES9039q2m in ASYNC mode without MCLK, with swapping 12Mhz processor crystal to cheap normal oscillator. Near the same was on another XMOS boards. This thing don't need and perhaps can't to be measured, it need to listen.
Sorry, but USB clock has no impact on audio when UAC2 interface is bit perfect to 32 bits. If it isn't bit perfect then there is something seriously wrong and swapping clock is not likely to help. Claims from listening when no proper controls are used and AB is not even possible are as convincing as fairy tales.
If the USB clock is causing some real audible effect, then it would almost certainly be due to analog noise side-effects and not because of bit errors. A well-designed isolator/reclocker system would hopefully take care of any poorly defined analog USB subsystem noise problems more effectively than a poorly defined reduction in USB clock jitter related noise.
This was about USB clock jitter, not USB clock noise (actually that 26MHz crystal is a reference clock, not USB clock). How would jitter in this reference clock cause audible analog noise side-effects (whatever that means)?