I've designed a system for the ADAU1452, in building and testing, so far, I've found I'm not getting the expected clock signal from the clkout pin. I'm using a crystal with the onboard circuit and I'm getting the clock there and I've successfully performed the test described here; Testing USB communications between the PC and SigmaDSP . Adjusting clock settings in sigmastudio registers makes no difference. Series resistors on the clkout line from 22R to 100R make no difference. I've tried this with 3 different chips on two different PCBs and had the same results, so suspect it isn't due to damaged chips. At a bit of a loss really and not sure where to look! Anyone have any suggestions please, hopefully someone from AD will invite me to send them my schematic and PCB layout to double check!