General Forum

Re: Beolab 4000 Polarization issue?

Alex — Sun, 22 Apr 2007 06:24:58 GMT

I used to get the same kind of thing, shocks off BeoCenter 2s and pretty much everything, along with my laptop and even my touch sensitive lamp. Since I started wearing Vans I don't get it any more, maybe something to do with your soles?

Re: Beolab 4000 Polarization issue?

Keith Saunders — Sun, 22 Apr 2007 01:58:55 GMT

Stevo,

I suggest that next time it happens you get a multimeter on the AC range and put one lead to mains earth and the other to the metal case of the Beolab 4000's and I am sure you will see a voltage of anywhere between 10 & 40 volts. If so, thats what you are feeling.

There are several causes for this problem and there is certainly nothing wrong with you B&O or other products. The cause is normally related to the electrical installation in your building or house.

In the US a lot of buildings/house actually receive 220 volts into the building/house which is used directly by such items as washer/dryers, but the power phase is split with the centre tap becoming your neutral of all your sockets and the two other ends providing the 110 volts at the socket meaning one socket could be on a different phase to another. All the time that current drawn from both halves is the same you will not have a problem, if there is a lot of current is drawn from one side but not the other then you are likely to have the problem.

This problem can happen for a different reason in the UK and that is why in most modern home here have neutral and earth bonded at the incoming supply point.

This type of problem is most common in older properties.

Keith..

Re: Beolab 4000 Polarization issue?

stevo4 — Sat, 21 Apr 2007 09:52:32 GMT

Keith,

Thanks for that very detailed response.

Years ago, when i was first getting into Hi-Fi, i first noticed it with my Pioneer Sx-580 Receiver and all that was needed was to unplug the unit from the wall and rotate the plug 180 degrees, and the problem/grounding went away. (And i should probably have titled the Thread as "Grounding Issue" rather than polarization (which is usually a problem with speakers when you accidentally connect the speaker wires backwards on only ONE speaker. (ie. right speaker - red to red, white to white & Left speaker red to white, white to red) Which in turn just kills any chance of 'sweet spot' center imaging (but you knew that).

But back to the issue - Strange. Last night when i went to bed, i turned off the BS4 but left the 4000's on like i usually do. This morning, got up and did the 'test' against the speakers and surprisingly felt NOTHING. I turned on the BS4 to see if that would affect anything and still no problem. Very Strange.

I am going to file this one under 'monitor'. And to answer your question, no, its not static buildup but a (was) constant light sensation feeling against the skin.

Thanks!

stevo

Re: Beolab 4000 Polarization issue?

paddy2042 — Sat, 21 Apr 2007 08:08:05 GMT

My Mac Powerbook does it too - it is really disconcerting. Sometimes if the inside of my forearm touches the corner of the Powerbook I get a semi shock - it is really uncomfortable.

paddy2042

Re: Beolab 4000 Polarization issue?

Coolskin — Sat, 21 Apr 2007 03:48:52 GMT

My PowerBook G4 has the same effect on me ...

... when the 230V mains is connected.

On battery power the feeling is gone.

So (i think) nothing to worry about.

Re: Beolab 4000 Polarization issue?

Peter — Sat, 21 Apr 2007 02:34:20 GMT

I noticed the same with some Beolab 8000s in my local showroom. Seems to be a common trait.

Re: Beolab 4000 Polarization issue?

Keith Saunders — Sat, 21 Apr 2007 02:07:02 GMT

Stevo,

When you talk about "wrong polarisation vibration" Are really talking about static discharge? quick belt or constant belt when touched ?

What do you have your BeoLab 4000 connected too?

Whilst your mains plug has three pins and your mains socket is earthed, the mains cable which goes into the BeoLab 4000's is two wire only, meaning there is no earth from the mains. The electronics earth inside and the chassis earth must be isulated from each other.

In fact in the BeoLab 4000 service manual it even has an insulation test. In the test procedure it warns that flashovers must not occur during the test procedure. The procedure short-circuits the two pins of the mains and connect them to one of the terminals of the insulation tester. They connect the other terminal of the insulation tester to the ground of the phono socket (Line in) They then wind the insulation tester up to 1.1 kVolts.

Whilst you are unlikely to have an insulation tester known as a megger in the UK, if you have a standard multi-meter you could test between the phono earth and the two mains pins with the powerlink cables unplugged.

Keith..

Re: Beolab 4000 Polarization issue?

Dave — Fri, 20 Apr 2007 22:32:03 GMT

Sounds like a flaw in the product, shock horror lol. It sounds like there is nothing wrong with your speakers. If they sound fine, then i'm almost certain that they are fine and there is nothing to worry about. This kind of thing happen with much cheaper electroncs. My philips dvd recorder does it.

Re: Beolab 4000 Polarization issue?

stevo4 — Fri, 20 Apr 2007 21:52:59 GMT

Have i actually stumped the group? No replies?

You guys know what i'm talking about right? when components aren't grounded right and you lightly run your finger along the face of the amp, tuner, etc. it kinda feels funny. That's what i get with the 4000s.

Thanks.

Beolab 4000 Polarization -Grounding issue?

stevo4 — Fri, 20 Apr 2007 13:49:27 GMT

First: I'm located in the US.

Today, while moving my Bl 4000's on their stands, i by chance gently slid my fingers over the speakers (both L & R) and felt the famous 'wrong polarization' vibration. I never noticed it before and checked the Power strip (which is a 3prong plug and can only be plugged in one way and then the plugs for each of the speakers. The speakers are also designed to go in one way and were plugged in correctly. I know the wall socket is grounded correctly too.

Any clues what's up or what i'm missing?

stevo