Hey, thanks for your detailed replies! Great stuff! With my trusty little multimeter I now found out that there is an increasing voltage on the turn-on lead of the majestic amp. It goes from 0.5V to over 1V within abnout 1-2min. I guess that's the culprit. I've taken the majestic amp off for now and its turn-on lead is also disconnected. Now I don't get any thump anymore, so I guess that's fixed now. Is there a permanent solution to the problem other than exchanging/repairing the majestic amp? Any ideas for stop-gaps?