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Humming sound from speakers

 

andrew keller
Bronze Member
Username: Kinggimp82

Post Number: 26
Registered: May-05
Posted on   
i have a cord running from my pc to my reciever. when no music is playing my speakers make a humming sound. is this normal or can it be fixed?
 

Jan Vigne
Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 6941
Registered: May-04
Posted on   


It depends on how loud the noise is. Do you have the PC and the receiver plugged into the same AC circuit?
 

andrew keller
Bronze Member
Username: Kinggimp82

Post Number: 28
Registered: May-05
Posted on   
the pc is a seperate room. the noise isnt all that loud but its irritating. the higher i turn the volume on my reciever the louder it gets. but when music is playing i dont notice a sound.
 

Berny
Gold Member
Username: Project6

Post Number: 4522
Registered: Dec-03
Posted on   
How long is the cord?
 

Jan Vigne
Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 6948
Registered: May-04
Posted on   


You have a different ground potential on the two systems. There is no easy way around the situation without either arranging the systems to both run off the same circuit breaker, have a common earth ground or possibly lift the ground from one end of the system.



 

Frank Abela
Gold Member
Username: Frank_abela

Berkshire UK

Post Number: 1089
Registered: Sep-04
Posted on   
Jan is on the money. It's an earth loop (for more info about earth loops see http://www.jaycar.com.au/images_uploaded/humloop.pdf).

I see you say PC to receiver. Is this a coax or fibre optic connection? If it's coax, switch to a different source. If the hum is still there (should be), disconnect the coax input from your PC and the hum should go away. If this happens, it's definitely the earth potential. You can get around this by changing the coax to a fibre optic connection, effectively breaking the loop. Of course, if you're using the PC's built-in DAC, then I'm not sure how you could break the loop.

regards,
Frank.
 

sanjay sh
Unregistered guest
Posted on   
use very good quality rca good shield cable if connection very long.

use good sound card like creative 24 bit.

your pc power supply might not be good.
can give out rf interference.

switch off the pc and check hum level.



 

DeathToEarthLoops
Unregistered guest
Posted on   
Earth loop it is! I had the same problem; my receiver is connected to both TV and PC via ordinary sound cables, the PC is grounded via powersupply and the TV is grounded via the coaxial antenna cable. Let the humming begin... :-) I had to unplug the antenna cable (easiest one to reach) in order to avoid the humming. But today, I bought one of these:
http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=PF8VNT3%2DGR

Now I run the antenna cable through this box, and then the electrical ground and antenna ground have the same "zero", so there is no current in the earth loop. Hey presto, all problems solved! And the gizmo even protects your stuff from lightning etc., and for me it's a bonus! Buy one!! Highly reccomended.
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