I too notice a high, metallic 'ping' sound from my Ayon CD5s when changing sources; and it locks on to new source; its just a blip then wonderful and warm sound. I use balanced IC's from Ayon, but run it into a tubed VAC preamp; then out balanced to my solid state amps...so its not just when using the preamp function of Ayon that it 'pings', must a blip in its design; but I just get used to it; and don't worry about it anymore. No harm, no foul, but I do enjoy its wonderful sound stage; and detail and warmth...