General Forum

Re: BC9500 2way IR audio interference

stevequinn — Thu, 08 May 2008 04:01:22 GMT

Hi Keith,

They are homemade from microphone cable - 4 core + shield. This may sound strange, but you may recall I was having problems with the Penta 'mixing' the channels, so I made these cables to carry only one audio signal each (ie a left cable and a right cable). I think I also mentioned that one of the pins on the DIN socket was isolated inside the Penta units, thus reducing the number of wires I required, so a total of 5 was all I needed for the data to the display, the power-on relay signal, and the audio. The shield is used for the data gnd. Unfortunately the shield surrounds the four cores...

Having said that, I previously used cables made from cat5 network cables, and I'm sure the IR noise was still there... (which is probably not surprising)

So I guess the answer will be to order some B&O cables, but I'd still need to de-solder the audio on one channel on each cable. Unfortunately there is not a great choice of cable suppliers where I live.

Naturally the cables each run from the BC9500 to each Penta because of the audio signal wiring. Ideally I would like to sort out the audio mixing issue and use standard fully wired cables!

If I could find a cable with 3 cores + a shielded wire that might work...

Regards, Steve

Re: BC9500 2way IR audio interference

Keith Saunders — Thu, 08 May 2008 02:42:57 GMT

Well, that's positive..

What type of Powerlink cables are you using, are they:-

Standard B&O fully wired type ?
Your homemade cables ?
How long are the cables ?
Are they daisy chained from one speaker to the other.

Re: BC9500 2way IR audio interference

stevequinn — Thu, 08 May 2008 02:28:27 GMT

OK, just had another look and tried what you have suggested - I first listened on the passives in the MCL linked room - the hum was present at zero volume even with the Pentas in the main room muted. I then disconnected the powerlink cables at the BC9500 and the noise is gone in the linked speakers... so it is my powerlink cables, then... Hmmm. Or, could it be crosstalk within the Pentas?

Thanks

Re: BC9500 2way IR audio interference

Keith Saunders — Thu, 08 May 2008 01:41:02 GMT

If that is the case:-

Do you have an MCL connections ?
Do you have an earth connection to the socket above the phono socket ?
Have you connected a couple of passive speakers to the passive output and disconnected the penta's to see if the data signal on the powerlink cables could be transmitting the IR in the form of crosstalk ?

Based on your feedback I would say that the problem is either an earthing problem or crosstalk picking the IR (digital signal) on the powerlink.

Re: BC9500 2way IR audio interference

stevequinn — Wed, 07 May 2008 18:16:34 GMT

Yes, I think it has always been present - audible from both speakers, particularly when playing a CD loud...

Re: BC9500 2way IR audio interference

Keith Saunders — Wed, 07 May 2008 14:41:49 GMT

Steve,

Have you always had this problem or has it only recently started to occur ?

This problem certainly should not occur, so I think the first step is to get a little more data.

Given, the last line of your posting I am assuming you have always had this problem ?

Does the "hum" occur in both speakers ?

BC9500 2way IR audio interference

stevequinn — Wed, 07 May 2008 06:49:12 GMT

Hi Beoworlders

Has anyone noticed and 'fixed' the IR interference I notice on my Beocenter 9500 when it sends a two-way IR signal? It is like this short buzz or hum and it seems only to be audible on the send cycle of the two-way IR - nothing when I hit a button on the beolink handheld, but a second later a hum from the speakers (BL Pentas)... it always sounds the same frequency which perhaps it a dud filter cct somewhere?

I find it hard to believe B&O would have been satisfied with this interference...

Cheers, Steve