[johnsonad]

I need a little help. I just moved into a new apartment in the same building and after hooking up my 2 channel rig I am getting a constant hum out of the speakers. Not only that, but now I hear the transformer in my CDP humming and the same in the amp. This was not present in the other apartment. I tried switching plugs etc. It is constantly there. I put in a trouble call for an electrician to check it out but what should I tell him/her when they get here?? That there is a bad ground somewhere and I can hear it in my speakers? Any help here would be appreciated! If they can't fix it for some reason, how do I over come it?

Thanks!

 

[bigshot]

Try grounding your equipment to the center screw in the faceplate of the power outlet. If your building is not terribly old, that should be a clean ground.

Also check to see if it's line noise from a refrigerator or AC unit.

See ya
Steve

 

[jcx]

the xfmr core buzz/hum could be from DC on the AC power lines (easily measured with properly rated multimeter but requires probing the hot line - know what you're doing or wait for the pro) - maybe caused by a lot of SCR commutated load somewhere in the building?

also improperly gnded equipment elsewhere could be puting noise into the safety gnd

try to use one power strip for everything in the audio system, some buildings have outlets in the same room on different branch circuits (measurable as AC diff between neutral/return of different outlets)

 

[IPodPJ]

Do you have any fluorescent lights on that circuit? If so, get rid of them. They are a no-no. And it's best if your refrigerator isn't on that circuit either, if at all possible. I suggest getting yourself a power conditioner if you don't have one. It is a necessity for any audio enthusiast who lives in an apartment.

 

[johnsonad]

Thanks everyone. All of my core gear is plugged into a conditioner (CDP/TP/amp/phonostage). Of the 4 outlets in the living room, each has a little different sound to it in varying tones and some louder/softer. Right now I have it plugged into the quitest outlet there. The place is only two years old and shouldn't have any of the old building problems. I'll have to look at the breaker box and see if the fridge or anything else major is on the living room breaker.

If the power company can't do anything about it, is there a specific type of power conditioner that works well with this problem or am I stuck with noisy power?

 

[johnsonad]

Quote:

Originally Posted by bigshot /img/forum/go_quote.gif Try grounding your equipment to the center screw in the faceplate of the power outlet. If your building is not terribly old, that should be a clean ground. Also check to see if it's line noise from a refrigerator or AC unit. See ya Steve

Thanks Steve. The AC unit is located above my bathroom and I hear a hum coming from the ceiling. Maybe this is the source of the problem.

 

[bigshot]

Turn it off and see if the noise stops. But my guess is that your outlet isn't grounded properly.

see ya
Steve

 

[johnsonad]

I haven't listened to it yet but got an email from the service people stating that they replaced the transformer in the AC unit. Hopefully this takes care of the problem.

 

[johnsonad]

So the AC unit transformer was replaced and there is no hum in the bathroom but the hum in the speakers remains. The oddest thing is that all of the transformers are humming too; CDP, power amp, speaker amps (built in sub amps). Do your transformers hum if you put your ear up to the unit?

 

[infinitesymphony]

I don't know if it's relevant to your case, but I've read about a lot of instances where audible transformer hum was caused by an incorrect power frequency. For example, if you plug a European 240V/50 Hz component into a 120V/60 Hz U.S. outlet, even with a voltage converter, you may still experience transformer hum; when I tried it using a European PCDP, the voltage converter also buzzed.

What make/model of power conditioner are you using?

 

[johnsonad]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif I don't know if it's relevant to your case, but I've read about a lot of instances where audible transformer hum was caused by an incorrect power frequency. For example, if you plug a European 240V/50 Hz component into a 120V/60 Hz U.S. outlet, even with a voltage converter, you may still experience transformer hum; when I tried it using a European PCDP, the voltage converter also buzzed. What make/model of power conditioner are you using?

One built by SACDmods that I've never had a problem with. The issue also happens with equipment not plugged into the conditioner (power amp/speakers) in different outlets. I'm going to test the line votage when I get home tonight. Maybe it is high....

 

[bigshot]

Could it be RF interference from some sort of police radio tower or something?

See ya
Steve

 

[johnsonad]

Quote:

Originally Posted by bigshot /img/forum/go_quote.gif Could it be RF interference from some sort of police radio tower or something? See ya Steve

Same building so I wouldn't think so. It improves when source/amp is plugged into the power conditioner vs. without it but doesn't resolve it completely. I posted in the DIY page that all of the transformers are buzzing too. Odd but probably something simple, what though I don't know

 

[haarvi]

Had hum in TV.
And when watching DVDs.
And through headphones in one of my two grounded headphone amps.
Hum disappeared when I disconnected the cable wire to the cable box.
Or when I put a cheater plug on the amp that was putting a hum through
to headphones.
Tentative diagnosis, arrived at through googling and various inquiries of those
knowledgeable about things electronica: ground loop hum.
Solution:
I just placed an order for a video ground loop interruptor.
To be attached to the cable line.
$59. From Jensen Transformers.
A ground loop interruptor to the headphone amp might also have resolved the problem.
I was told - by Jensen - that once the loop is interrupted at one point, the problem is taken care of.
An ground loop interrupter for the amp would have been about $170.
There are no doubt cheaper versions of ground loop interrupters out there.
My impression is that Jensen is a quality act.
(I read of someone whose hum went away when using a cheaper product but
was not able to get high defintion programming until he switched to the Jensen product.)
They will provide over-the-phone consultation.
(818) 374-5857
Website:
WELCOME TO JENSEN TRANSFORMERS, INC.

 

[johnsonad]

Thanks Haarvi, I'll look into that.