Hello all.

I have a problem with the following set up and wondering if anyone can help.

BS9000 with a pair of beolab 3's running with B&O PL cable (not bosscom). 

 

When the power is switched on the system and the speakers there is an annoying high pitched humming noise that I can't resolve.  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'm also getting a static charge onto the BS9000 floor stand to touch.  I have moved both items to another room where the same still happens but when I link the lab 3's with my BC2 the noise stops. 

Anyone had this problem before?

 

Thanks Ian

 

Sorry I forgot to sell hello (newbe) !!!!

There are others here better informed who will tell you exactly but I believe this issue has cropped up before (more than once) on this site. I seem to recall that there are different types of Powerlink cable and using the wrong type will lead to the problem you describe.

Oh and welcome to Beoworld - I hope you enjoy

Ian,

Welcome to Beoworld.

There are a very large number of reasons for the type of problem you have described, so we will need to narrow it down with a few questions as below:-

1. Has the Beosound 9000 and Beolab 3 configuration previously worked without the problem ? In other words has the problem occurred since you purchased or changed the configuration ?
2. What version powerlink cables are you using ? If they are standard B&O powerlink cables, if they are Mark III then there will be a small triangle on the plug next to the alienment key (dent in metal shield)
3. How long are your Powerlink cables ? Are they routed with power or other signal cables ?

Given that you say that you have connected the Beolab 3's to a BeoCentre 2 and do not have the problem, I am assuming you used the same Powerlink cables, please confirm.

Hi

The lab 3's are 2 years old and the BS9000 is a mk1 1998 (upgraded mk3 drive and chip-NUMUSIC etc) just had a full service by B&O.  The set up is new to me as the lab's were part of another system before which included the BC2 (rear speakers that weren't being used).

 I had Bosscom cables first of all but have now changed these for mk3 PL B&O cables (brand new).

 The PL cables are 10 meters long and are not yet chased into the wall (just hanging) but the power cables are not that far away.

 I also get the static in the stand when the BS9000 isn't pluged into the mains but just the lab3's are connected via PL and the lab3's  are powered up.

 ??????????

B&O are saying it could be an earthing problem....any idea how I earth a 9000???

Ian,

I agree, are you a technical person who has available a multi-meter ?

Ian,

The Beosound 9000 does not actually have a mains earth, just a signal ground like most modern B&O products. One effect of this is if you have a mains ground to neutral potential greater than a couple of volts you can get problems. So my next question is:-

1. Are you in an old or new house, in other words was the mains supply installed in the last 20 years ? The reason for asking is on modern homes the incoming neutral line is bonded to ground at your meter, older installations are not..So if you are in a newer home the problem is less likely to be a ground to neutral potential difference.

Hi Keith...yes its a new house (3 years old)

Ian,

That's good, it takes several options off the table provided there is no wiring errors in any of your sockets for example neutral and earth reversed behind the socket. There is really two ways of proving the point:-

1. Purchase a cheap (£5) mains tester from you local DIY store which you plug into your mains sockets and it tells you if it is wired correctly.
2. Connect a wire from the screen of your FM aerial input on the Beosound 9000 to mains earth. If you are using standard 75 ohm aerial plug for your FM aerial input, then wind the stripped wire end around the metal of the plug, the other end of the wire connect to the earth pin of a mains plug. Make sure it is connected to the earth pin at the top ONLY and plug in BUT do not switch on at the socket.

If after making the connection in point 2 above the problem goes away, then you certainly do have an earthing issue.

Thanks Keith I'll try this tonight.   When you say that I may have an earthing issue do you mean with the house or the 9000? 

Ian,

Actually, it could be either, however given you previously told me that the Mark I had been upgraded and "serviced" also means its been taken apart and therefore it is possible for a signal ground somewhere not to be correctly connected, equally any problems with your power neutral line could gives these type of issues.

The bottomline is we need to do various tests to narrow the problem down.

Hi

Please confirm that it is mkIII power link cable by looking on the DIN plug in the plastic there is a triangle. if not is mkI

Yes it has a triangle on the pl cable so I take it to be mk3.  Keith I tried the tests...firstly all the sockets pasted the testing unit, secondly the earthing seemed to get rid of the static charge to the stand but there was still a buzing in the speakers....hmmmmm what next?

Well Ian,

Based on your answers, the following are my conclusions:-

• Whilst you have a static problem, it is nothing to do with your Humming noise issue.
• Given you have new Mark III powerlink cables and you have tested the speakers on another system it seemds unlikely to be the speakers at fault.
• Whilst your mains tester is not full proof because you could still have a voltage potential between neutral and earth, but it seems less likely to be the cause.
• The most likely cause now appears to be the Beosound 9000 itself, given the recent work which has been done on the unit by your dealer. I am assuming here that nothing else whatsoever is connected to the BS9000 other than the mains cable, and powerlink cables to the speakers ? please confirm.

I think you should take the BS9000 back to the dealer who did the upgrades and have them check it. It seems most likely that a earthing screen or wire have not been put back correctly..

I have the same problems with my Beosound 9000 and BL3´s.

I use two different cables to them:

1 P.L Mk1 which gives a noise tone like a radio without any station at the frequenze.

1 P.L MK3 Bossocom with this cable you get a high frequenze noise instead.

Anyone with a solution for this problem?

 

Another humming scenario involving my BS9000 and Penta's.

Both were fine using Mk3 cable for beolab speakers with displays.....changed one of them for an eBay purchased 20 metre cable.

All ok, no constant humm, but I do get annoying hum\buzz when adjusting volume or tracks change on the one Penta that I have extended.

Have now purchased 20 metre mk3 from Lifestyle that I hope allows me to extend and does not give me hum\buzz between tracks...

It is worth knowing that part of diagnostics i laid 20 metre cable in middle of floor - well away from any power sources etc...

Will let you know in case it is relevant,

Thanks

Russ

You should be using Mk2 fully wired cables for Beolab Penta!

The buzz/crackle when you change volume/tracks sounds like a duff contact problem in one of the plugs/sockets

Common issue

 

You need to cut one of the powerlinks wires, can be easily done by cutting one of the plugs pins.  Contact your local service centre to check the correct pin. This is in their config guide.