Is it normal to hear a very slight hum coming from your speakers with no signal input

Duster

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Hi,
Can you please tell me, is it normal to hear a very slight hum coming from your speakers,
IE- with any input, and no signal being feed into the amp. It doesn't matter what the volume is set too, the hum is always the same volume. IE very low
You have to put your ear right next to the speaker, to hear the hum.

Thanks for any info
 
Maybe an analogue input should cause a little bit of humming for the speakers, but if its a digital input then that shouldn't happen. I turn my reciever up on a digital input and there isn't one bit of humming to be heard. I would suggest that you check all the phono connections, if they are slightly loose they will cause this background humming. If not then it could just be the general nature of your speakers. Hope this helps a bit
 
note: if the hum is constant at all volumes then it's 'source' is after the amplification stage, so checking your inputs will not fix it! what you'd have to check is speaker wire (i.e. connection to amp, routing - avoid running parallel to mains, ect.).

other that that, yes it can be normal to have some (very minimal hum) - and since you're saying you have to put your ears next to the speakers, I would ignore!
 
Sniper said:
note: if the hum is constant at all volumes then it's 'source' is after the amplification stage, so checking your inputs will not fix it! what you'd have to check is speaker wire (i.e. connection to amp, routing - avoid running parallel to mains, ect.).

other that that, yes it can be normal to have some (very minimal hum) - and since you're saying you have to put your ears next to the speakers, I would ignore!
HI,
Thanks for your replys,

Yes, the hum is constant at all volumes.

Ive moved all power cables away from speaker cables, this didnt help.

I can hear the hum from about half a meter away. I never heard any hum from my old amp. I tested my old amp and it does make a very low humming sound. That amp was not grounded, and this new amp is.
I wonder if it is something to do with the grounding?

it's probably just me being fussy :suicide:
 
The grounding could have something to do with it. Ground loop hums can be a problem and some receivers are equipped with a "ground lift" switch to attenuate this type of problem.
 
Ovation said:
The grounding could have something to do with it. Ground loop hums can be a problem and some receivers are equipped with a "ground lift" switch to attenuate this type of problem.

Hi,
Thanks for reply,
Yes my new amp does have a Ground lift switch, I tried that but it didnt help
 
special said:
Earthloop, you live in England I presume? You can fix it, remove earth.

Hi,
I'm from England, but i'm living in Germany at the moment.

You cant remove the Earth from a German power plug
 
It's unwise to blindly remove the earth from equipment anyway.

You may well just be hearing the noise threshold of one of the amplifier stages. I have a small hum from my speakers even with a digital zero applied (easily checked, just put your source to "Pause"). I really don't think it's anything to worry about. :)
 
eviljohn's point is entirely correct....lifting the earth connection should be viewed only as a last resort,and a potentially lethal one at that.

The likely cause is simply inherent hum from the power amp stages of the receiver,and with a sensitive set of speakers,this may well be audible,although if you can only hear it with your head next to the speakers,it's not a problem.

Owners of horn speakers,and SEt valve amps have far more trouble with this sort of thing.
 
Hi Guys,
Thanks for all the good replys,

I dont think I would remove the Earth wire even if I could, as the manual clearly states that the Amp must be Earthed.

I'm sure it's just me being fussy anyway, I'll just have to learn to live with the hum.
I'll try a mains filter and see if that helps.

Thanks again.
 
Duster said:
I dont think I would remove the Earth wire even if I could, as the manual clearly states that the Amp must be Earthed.
For future reference (or anyone else who's interested in this thread) you should only consider removing the earth on equipment that's been double insulated. In the UK at least this is easily checked as there will be a "double box" logo next to the power inlet (ie. a box within a box). You may also notice on some models that there simply isn't an earth connecting pin in the items inlet socket.

If this is the case (usually is on modern equipment) then you can remove the earth connection with no risk if you must. If this isn't the case then you must not remove the earth connection. BFD's for example must be earthed for electrical safety, removing the earth like they do on the Snapbug site is extremely foolish and dangerous, there are other better methods of removing audible hum. To a certain extent of course, audio amplifiers have an inherent noise floor and as alexs2 said, this will be more audible with sensitive speakers. :)
 
I have a NAD T763 and I also get this hum. It's discernable till about 1 m when no source is playing. I've been speaking to some friends and also from what I have read online and this doesn't seem to happen to everyone. Should I change my unit. I also have read something about regultaing the power input. Could this be a solution?
I'm wondering if equipment this expensive should have this kind of glitch
 
SRam said:
I have a NAD T763 and I also get this hum. It's discernable till about 1 m when no source is playing. I've been speaking to some friends and also from what I have read online and this doesn't seem to happen to everyone. Should I change my unit. I also have read something about regultaing the power input. Could this be a solution?
I'm wondering if equipment this expensive should have this kind of glitch


Hi,

Take your amp back to your dealer so you can test his amp, and your amp together, If your amp hums more than his, then it may be faulty, if not then it may be your mains feed. You could try a mains filter, but more likely, as others have said, its just the hum from the power amp stages , and nothing to worry about.
 

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