What sort of clicking noise - mechanical like a relay? If so, the relay is used to ground the output when there is no input - this may be due to loss of digital lock, or sometimes if switching DSP mode.

It may be that your new CD player when turned on keeps the digital signal on and valid at all times, but the other ones only output a valid digital signal when they are playing things. Just a guess.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).