Humming sound from AMP.. Dimmer switch??? (1 Viewer)

[Martin Jiang]

I just purchased a sherbourn amp, a beautiful machine. However, the machine emits some really annoying humming sound. I almost thought about returning it but then found out that the humming sound is associated with the dimmer switch in the room. If I turn the dimmer to the strongest. the humming sound is the biggest. but if I turn it lower or turn it off. The humming sound almost go away. It become very hard to spot and notice then.

Why would the dimmer cause such humming sound? it is obviously no the ground loop because it happens when NOTHING is connected to the amp. Also, the dimmer and amp are plug in to two difference circuit break. Why do they interfere with each other?

Thanks

 

[Martin Jiang]

Also, if you know what 's the cause. How do I eliminate that?

 

[Chu Gai]

because not all dimmer switches are created equal and are capable of radiating large quantities of garbage both through the attached wires or through the air. its my understanding that many dimmer switches are solid state devices that vary the power to the fixture by switching off and on. depending where in the power curve they switch dictates the voltage you get. It's like clipping the voltage. So what are the solutions...
1) put the light on a different circuit (sheesh, that would be a bit involved). no guarantees it'd work either.
2) replace the dimmer with simple on/off
3) replace the dimmer with a different model...not sure what to recommend here as one would want to return whatever it is they bought. not sure if your local electrical supply house would want to do that. home depot or lowes though take anything back. you might want to look at something from Lutron and/or incorporate what they call their 'lamp debuzzing coil'. Read a bit more about this and other things mentioned here:
http://www.lutron.com/product_technical/faq.html

 

[Kevin C Brown]

You could also try power filtration a la Monster, Panamax, or balanced power with PS Audio, Equi=Tech, Furmann, etc. Balanced power is the best filtering you can get for an AC line. And the PS Audio power plants, which are not cheap, actually can also "regenerate" the AC for you.

Another choice is to plug your amp into a different circuit.

 

[Chu Gai]

possibly Kevin if the problem isn't due in part to emission through the air. but maybe better to remove the stone from the shoe rather than see a doctor and take a painkiller. cheaper too.
btw, did you have this problem before you bought the new unit too?

 

[AlanWms]

Martin,

There is a relatively inexpensive solution designed specifically for what you are experiencing. Audio Prism makes some nifty little devices called Quiet Lines. If you plug one of these into an outlet that is on the same circuit as the dimmer switch there's a good chance this will eliminate or drastically reduce the "hum".

Alan

 

[Martin Jiang]

Thanks for all the response, I got my eyes on the monster HST2000 power conditioner,can this solve all my problem? I also have some speaker buzzing sound which I believe is from a ground loop. I plan to plug everything in the monster.

Gai, I never expenience this problem before. then again I was using a receiver, which probably not that complcaite

 

[Kevin C Brown]

...emission through the air.

Huh? It's electrical noise/interference thrown back onto the AC line from the dimmer switch itself. A dimmer switch switch isn't an RF device. Usually a simple resistive potentiometer.

 

[Chu Gai]

maybe Kevin. if by resistive you mean like a potentiostat (variostat) then it's highly unlikely it'd either emit any EMI down the lines or through the air. In fact that's one way of tackling the problem, by using a variostat device from a company like Staco. It's expensive though. I once had a halogen dimmer that gave a hum. Closer I moved it, louder the noise became. Sounds to me like that was a classic case of EMI coming through the air at least in part. in any event, if he's defined what the problem is, it's more effective to attack the root. well at least to me it is.

 

[Kevin C Brown]

But one should always have at least surge supression on their AC line, and it is well know that digital devices like DVD players, CD recorders, etc, throw "hash" (digital noise) back into the AC line, so an all-in-one AC box potentially addresses more than 1 problem anyway. An AC box can also deal with things like ground loops too.
But yeah, might be cheaper just to swap the dimmer switch for a different kind, or get rid of it altogther if that's possible...
(I had a halogen dimmable torchiere that I used on its lowest setting for "backlighting" when watching DVDs. When I switched amps, gawdaweful hum. So I chucked it and went with an incandescent lamp with a 7W bulb.)

 

[Chu Gai]

i've got a couple of dimmers that lead to incadescents (track lighting and some overhead lights) that just happen to be on the same circuit while my son, in his bedroom, has the notorious halogen dimmers that don't cause problems. but i think this is largely to due with better dimmers. interestingly, i've heard these complaints with far more frequency from those who use separates which for many involves using the receiver as a pre-pro. the implication to me, since it didn't occur with the receiver but did when it was used as a pre-pro, is that of radiated EMI interacting with the interconnects. again, simpler to change the dimmer rather than start investigating twisted pair interconnects with shielding. as far as a surge protector acting to stop stuff connected to it from dumping stuff down the lines, that's not their function and the effectives of any RF choke that might be installed on the wire to the protector would depend entirely on the nature of the power supply of the attached equipment. myself i don't agonize over a little AC impurity but if one does, it's going to cost you.
My position on surge protectors is that if you're a homeowner, you should get a whole house one first. properly sized and properly grounded, those will work and they'll protect everything electrical in your house. for a homeowner concerned about protection and not doing that, installing a point of use unit in its place is the one of the worst ways of spending one's money. the cost on a per protected appliance basis is high, the protection is highly questionable. after that if you want a little localized protection from baby transients, there's a slew that you can choose from with my preferences leaning towards silicon avalanche diodes, either alone or in concert with MOV's because of their low clamping voltages.

 

[Philip Hamm]

Thanks for all the response, I got my eyes on the monster HST2000 power conditioner,can this solve all my problem? I also have some speaker buzzing sound which I believe is from a ground loop. I plan to plug everything in the monster.

If you have a ground loop problem the power conditioner will not help. If your dimmer is causing the problem (highly probable - they are notorious for this) the power conditioner won't help either. However, a quality surge suppressor (as opposed to a $10 one) is a very good idea for expensive home theater equipment. If I were you I'd remove the dimmer switch and see what happens.

 

[AaronBatiuk]

A dimmer switch switch isn't an RF device. Usually a simple resistive potentiometer.

A resistive potentiometer? No. The power dissipation in the dimmer switch itself would cause it to melt, or better yet, start a fire.
Dimmers work by switching the lights on late in the cycle. The 60 Hz AC in north america is cyclic, with 120 power cycles per second. If the dimmer switches on halfway through each cycle, the lamp will use half the power, etc. The later in the cycle that the lamp gets turned on, the dimmer it is.
Any device that switches high power electricity on and off is an RF device, and can cause interference to just about anything electronic.

 

[Kevin C Brown]

If your dimmer is causing the problem (highly probable - they are notorious for this) the power conditioner won't help either.

Not true either. The balanced power unit I have also solved the buzz/hum problem I had with the halogen dimmer.

 

[Philip Hamm]

Kevin, do you think any of those devices would help with my 60 cycle hum problem as described in my long thread in the tweaking section? Please read it if you have some time as it appears you may have some good ideas as to how I can resolve a similar problem in my house. In my house the problem is caused by my refrigerator - when the compressor motor runs the separates system hums. If you can point me to a power solution that doens't mean I have to pull my breaker panel and switch circuits I'd be really happy.Read about it here.