Popping speakers

[MORGEY]

Does anyone know why this happens? When I switch my small laser light on or off there is an annoying pop from my speakers. The unit is the only lighting effect that does this and is the only one that is operated through a 9v transformer. Is this causing or going to cause damage or is it ok to live with?
Thanks:D

[Totally Plucked]

Does it have a good earth connection :confused: :confused:

[MORGEY]

Yes the transformer does. The laser unit is new and appears to work fine.
I may get it pat tested with the transformer to see if there is a problem.
What I wondered was, is this type of problem fairly normal or should it definately not happen?

[Nightowl Discotheques]

how are you switching the effect on ?

[CRAZY K]

Does anyone know why this happens? When I switch my small laser light on or off there is an annoying pop from my speakers. The unit is the only lighting effect that does this and is the only one that is operated through a 9v transformer. Is this causing or going to cause damage or is it ok to live with?
Thanks:D

Its probably bad earthing--or no earthing -- :eek: as long as the lead passed a recent PAT test I wouldnt worry--

I see my 6 volt Cortex Power Pack has no earthing at the mains plug---so thats the answer.

But then that doesnt get switched on and off all night so I dont know if it crackles:confused:

[MORGEY]

Thanks for that Crazy K.
Nightowl I think the answer is an earthing problem as you said how am I switching it on and off. I am literally switching a 13 amp socket on and off at the moment and there I think is the problem. The transformer is the 13 amp plug in type and passed a pat test.:)

[Digital Jack]

Are you positive it's earthed at all ?
If the unit runs off of a power supply I imagine you mean what the Americans refer to as a wall wart.
Wall warts in most cases just supply power along two wires to the desired appliance , if so , the laser wont have an earth.
Look at the earth pin on the power supply , if it's plastic you will not have an earth.
In the above cases you should have a symbol of one square inside another square marked somewhere on the power supply.
The two squares indicate that it's double insulated and no earth is required.
If all is well you could always consider fitting a rocker switch on one of the two wires that run from the power supply to the laser (preferably on the positive (+) wire , you could then switch the laser on and off without introducing the pop noise to your system.
A PAT test just shows that the item is safe to use , it doesn't test for quality of build or suppression.

[DAVESOUNDS SERVICES]

The Popping is because you are making and breaking a highly inductive circuit
IE The Laser mains transformer.
and its putting a spike back ito the supply thats trying to damage your speakers and certainly your laptop!
best solution is to use a switch pack to control the effect.
If your simply using a 13 amp wall socket your asking for trouble.
PAT testing will not help
( it should be tested anyway)
cheers Davesounds

[MORGEY]

Thank you all for the good advice. I will get this sorted asap.
A switch pack seems to be my best quick solution.

Thanks:)

[DAVESOUNDS SERVICES]

Your most welcome...
When you buy a switch pack make sure your getting one thats actually suppressed
and not just a row of cheap swithes in a pretty box

DAVE

[addoaddo]

This is not an earth problem and certainly not a PAT test problem. Most plug in transformers are class 2 which do not have an earth.
I am not convinced that even switch pack would make any difference. It is most likely caused by RF. A lot of energy is used to fire a laser and if the circuit is not designed correctly it will leak out and interfere with other devices. That is why electrical equipment should comply be the test for CE marking.

Is there a switch on the actual unit as this might be better otherwise I expect you will have to live with it. It is unlikely to damage your speakers (depending on level) but does not give an professional appearance to the customers.

[Excalibur]

This is not an earth problem and certainly not a PAT test problem. Most plug in transformers are class 2 which do not have an earth.
I am not convinced that even switch pack would make any difference. It is most likely caused by RF. A lot of energy is used to fire a laser and if the circuit is not designed correctly it will leak out and interfere with other devices. That is why electrical equipment should comply be the test for CE marking.

Is there a switch on the actual unit as this might be better otherwise I expect you will have to live with it. It is unlikely to damage your speakers (depending on level) but does not give an professional appearance to the customers.

Well obviously switching 9v rather than 240v would cut the pop considerably I would expect. In the old days, a capacitor across the contacts was a favourite for suppression, but I'd be inclined to try a switch pack first and see what happens. If there's no improvement, I think taking it to a qualified electrician is next, or bin it and buy a different one.

[CRAZY K]

Well obviously switching 9v rather than 240v would cut the pop considerably I would expect. In the old days, a capacitor across the contacts was a favourite for suppression, but I'd be inclined to try a switch pack first and see what happens. If there's no improvement, I think taking it to a qualified electrician is next, or bin it and buy a different one.

Thats true, I remember on the old fashioned decks there was a start switch which needed a capacitor across it to suppress the click.

Although the old equipment ( like cars) was far easier to fix parts than the modern stuff.