Amplifier hum

Gentlemen,

My amp hums when my wife uses a hairdryer from the same room and my daughters room. It immediately stops when hairdryer switch off. My house is installed with 3 phase wiring. The amp even hums when on standby. Does that mean the 2 rooms are sharing the same phase? Will the humming have any long term adverse effect on the equipment and what can i do to prevent it?

Thanking all of you in advance.

Maybe this could help:

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wah.. u can hear the hum while the hair dryer was blowing away?

I believe there is some noises from the Life or Neutral that is being bled to the ground.

What amp you are using? and do u have any basic electric noise filter?



Lifting the ground at the amp could sometimes solve this problem; but it is not something u should do if your amp is running on 3 pin plug from the beginning.

Ya..i also read that lifting the ground is not advisable. Krell with a 750va transformer and no basic noise filter. It is plug straight to a US pin wall socket.

oh ok. a good quality amp. So cant be the transformer acting up.

You may need to do some troubleshooting by isolating all possible cause that lead to this..

Since you can simulate the condition by switching on the hair dryer.

I suggest you to unplug interconnect to the amp 1 pair at a time and on the hair dryer to identify where it is coming from.. sometime, it is not from the amp. can be the source.

Good luck.

Tried one pair at a time. Also unhooked the speaker wires. Atlast, disconnect everything except the power cord. Amp on standby. Problem persist.

I think it's the interference (electrical noise due to poor suppression)coming from the hairdryer motor into the mains and picked up by your amp.

Yeah, i kind of agree with CT-Boy.

Have you considered asking her to shave her head bald so eleminating the need to....

Sorry! So so sorry!! Could not let that one go... In a sstrnge mood past few days. Probably not helping you much.

Would an isolation transformer help.... but for krell power, it would be kind of mahal...

Bal...

Is your amp and other rig earthed?
Are you sure your home electrical earth is in ideal or perfect order?
Home earth system is often ignored thinking it last forever the lifetime of the home. If unsure, please employ a competent electrical contractor to check and rectify your home earthing system, not only good for hifi but other safety aspects.
The home earth system can rot away or go missing (due to remodelling the home) in 10 years. I've heard of horror stories because of this especially during lightning strikes, bye bye TV, bye bye some other expensive home appliances.

Gentlemen, my apologies. I think i got the term humming misleading. just took the same hairdryer to the dealer and his demo amp suffered the same problem. It sounds more like a light rattle and according to him, it is due to the hairdryer sucking the current from the common phase. My hifi outlet is definitely sharing the same line with the hairdryers outlet. He suggested a dedicated line direct from the fuse box.

Perhaps you can just interrupt your listening session for a few minutes while the women of the house do their hair-drying. During the few minutes you can get a cold beer from the fridge and get comfy, ready to continue the listening session.

That will keep things simple without having to do any major re-wiring and the savings could be used for other things (hifi accessories etc.)

hello Ongaaron,

Refer back to ur first post again, you also mention it hum/rattle by itself even without the hairdyer power on.

So I think there are 2 isolated problem here. 1. of course is the noise from the hair dryer. 2. Noise from your amp.

So it means without the speaker being connected, u still hear noise from your amp?

If it is a decade old amp, probably the transformer is acting up, where the bolt tighten it to the chassis comes a bit loose. Well you of course can Macgyver yourself, if u really know what to do about it. Do note, that this cannot be over tighten, as it will damage the transformer. also, chance is this may not solve your problem. it maybe the transformer winding itself that already loosen up. If you can't bear with it, u need to have it rectified by the authorise dealer. Also, the source of such hum/rattle may not be coming from the transformer, but other panel or PCB in the amp being loose.



Mean time, your hairdyer.. better not use it or buy her a new one. it must have generated rather unusual electric flux or arc. Otherwise, you should not hear anything from the amp or speaker eventhough a hairdyer is attached on the same power outlet.. not for your Krell.



Haha, we just can't let you go over this issue, didn't we?

Adrian, what i meant was when amp on standby, when hairdryer is on , there is a rattle/hum.When hairdryer off, it is silent when on standby and when switch on.

This humming sound during standby, is it coming from the amp? Not from the speakers, right?

Yes, from amp only