Need help with noise in my speakers

7 replies
H(
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Hank (archived)
Bronze
Posted March 16, 2009 at 02:51 GMT
#1872285

Hello

I have a problem with my BS9000 and a pair of beolab 3.

When the power is switched on the speakers there is an annoying high pitched humming noise that I can't solve. 

The noise is present all the time even when the music is playing (only heard at low volume and is drowned out at high volume).

I have used different type of powerlink cables but all of them give some kind of noise.

* Bosscom "white cables" MK3 gives a high pitched humming noise.

* Bang&Olufsen orginal MK3 gives a high pitched humming noise.

* Bang&Olufsen Beolab 5 Powerlink cables gives a high pitched humming noise.

* Bang&Olufsen orginal MK2 cables doesn´t sound like the others, with this cables I get a noise like a radio signal.

I heard that it could be possible to disconnect one of the pins in the P.L cable to get ride of noise is that correct?

Anyone with an idea of what it can be??

 

Best Regards

Hank

W(
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wirralsimon (archived)
Bronze
Posted March 16, 2009 at 05:24 GMT
#1872286

Have you tried the Beolabs with a different source and the Beosound with different speakers so you can narrow it down to the source or the speakers? It might not be the cables at all!

 

Simon

L(
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liberal (archived)
Bronze
Posted March 16, 2009 at 06:29 GMT
#1872287

Dear Hank,

 

I think this may be due to the additional reference grounding on the BeoLab 3, I had the same problem with my BeoSound 9000. This is what the B&O Product Configuration Guide recommends when connecting BeoLab 3's to a BeoSound 9000

 

 ‘When connecting the BeoLab 3 to BeoSound 9000 type 252X, you might hear

a constant weak howling tone (ca. 7kHz).

Modify the Power Link plug on the cable nearest to the BeoLab 3 as follows

cut the wire to pin 7  short-circuit pins 2 and 7.’

 

Hope this is of some help.

 

P

 

 

 

 

K(
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KingOfSnake (archived)
Bronze
Posted March 16, 2009 at 08:07 GMT
#1872288

Low Voltage Lighting?

H(
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Hank (archived)
Bronze
Posted March 17, 2009 at 11:00 GMT
#1872289

Thanks "Liberal" for your suggestion.

I will try to modify the cable and test it.

I have to find a good way to cut the wire to pin 7 and shortcut between pin 2 and pin 7.

Can I do this shortcut in the contact?

 

"KingofSnake" what do you mean with low voltage Lighting?

 

Best Regards

Hank

H(
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Hank (archived)
Bronze
Posted March 18, 2009 at 10:40 GMT
#1872290

I don´t get this problems with my Beolab 4000, but it might be Beosound 9000 that cause this noise.

 

H(
Offline
Hank (archived)
Bronze
Posted March 18, 2009 at 15:16 GMT
#1872291

I have now connected the speakers to the computer through a PL to RCA cable.

With this connections the speakers sounds like them should.

Next step is now to modify the PL cable and try again.

If it doesn´t work it must be Besound 9000 that send some kind of noise to the lab3s. But why can´t I hear this noise with Beolab 4000?

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