Dear fellow enthusiasts,
I now recapped and restored 4 pairs of Beolab 8000 with good success. They all had the same issues in more or less evolved states. Besides the crappy PCB-quality a common problem is silent humming which is even a little louder when switching to the rca-connector. You can disuss about ground loops, but that is not the problem when you don't connect anything to the speaker except the power cable. So I investigated it a little more and found out that humming vanishes when you disconnect P4 (audio connector) from the main PCB. Connecting the cable (Looks a little like a 90s audio cable from a cd-player) WITHOUT connecting it to the plugs in the foot of the speaker already gives the humming. The cable is being routed below and close to the transformer. So I assume the noise is being induced by the transformer.
Did anyone of you solve this design issue on the speakers?
Greetings,
Martin