So i already resolved a general issue with my sound card that was creating weird behaviour (connection drops, no audio coming through etc.) simply by replacing the power supply.

Now i observed some other weird behaviour, the cause of which is unrelated (i think). It doesn't create any major problems for me, it is more something i am just curious about.

Generally, the ADA8000 as well as the FF400 function just fine. But when the ADA8000 is already powered up first and my soundcard is idling (meaning my connected music pc is either turned off or still booting up = whenever the red LED on the FF400 is on), weird noise is being sent out the FF400's analog outputs. I can't monitor the ADAT outs (nothing hooked up) other than through Total Mix, which is of course inaccessible when the FF400 is offline.

The signal is audible in my headphones on outputs 7/8 and signal is also being sent out through the other analog outputs (i have a external audio pulse-to-midi clock converter hooked up to 2 other line outs on the FF400 and that clock's LEDs are also blinking rapidly, confirming that it's receiving some fast jittery signal as well)

To be clear, this noise being sent out only happens when the ADA8000 is powered up and the RME is idling. My guess is that it is maybe the sample rate clock signal that is audible somehow? It sounds like a pulse train of sorts.

The ADA8000 sends its audio out through ADAT to the FF400, and the ADA8000's sample rate is being clocked from the FF400 through a word cable. Once everything is started up, there are no issues - i am just very curious if the above is normal during startup, and what causes it.