I have updated my GLD80 to firmware 1.40.
Now I have a noise on all channels that are linked on my AR2412.
When I unplug the cat5 cable, the noise is gone.
I contacted a collegue and he has the same problem (he also owns a GLD80 with AR2412).
I downgraded to 1.30 but the noise is still there.
What does the noise sound like? What do you mean by “all channels that are linked on my AR2412”, all channels getting signal from those preamps, or channels which are ganged in some way?
It’s probably a clock sync problem, check that first in Setup > Audio > Audio Sync.
Edit: What about the output sockets on the 2412, any noise on those?