ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
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
Hello Martin,
I have the exact same issue and I have found no solution either: my speakers hum when plugged in, even without any input (RCA or Powerlink).
I found that touching the speaker tube changed the hum a little. I thought it could be foam rot, but it is not (I've cleaned mine thoroughly).
Reading your message gave me hope then! Have you found a solution, like rerouting some cables further away from the transformer?
They seem awfully close and maybe the foam tape B&O used before was more insulating when it was new.
Cheers! Henri
Little hum by bl8000 is totaly normal...if RCA connected humm is more noticable.. or 50hz humm ..that is cose bad cables.
Yes, all my 4 pairs of restored BL8000 do that, especially when using the rca jacks. But that doesn´t mean it is o.k. The reason is bad circuit design of these cheaply produced electronics. If you disconnect the internal cable from the foot from the mainboard, the output is dead silent. At first I thought that the routing of the shielded audio connection cable directly under the main transformer is not a good idea, but routing somewhere else doesn't help. Now I am thinking of narrow twisting a new connection cable to prevent induction from the transformer. But I have the suspicion that the grounding concept is just bad.
Did anyone of you try a twisted connection cable from the mainboard to the foot of the speakers?