I have created my own ADAU1701 test board and successfully created a simple test program that routes the analog input to the analog output.
The samplerate is set to 48kHz with a 12.288MHz xtal. PLL_MODE0 pulled low and PLL_MODE1 pulled high (256*fs).
After powering up the DSP and pulling Reset low and high there is good quality audio.
Everything seems to be ok by now.
But now, I want the samplerate to be set to 192kHz for future projects. After setting both the DSP core and the analog inputs to 192kHz and changing
the PLL mode to 64*fs @ 12.288MHz, both PLL_MODE0 and PLL_MODE1 pulled low, there is no audio. Just a loud noise (like a radio which is not recieving signal).
All power supply pins are decoupled correctly with 100nF and 10uF. The only thing what could be causing this problem (I think) is the use of a break out board for the ADAU1701 (long leads).