Low level buzzing coming from tweeters.


I now have a low level buzzing coming out of my tweeters even when i am in mute. It happens even with the amp on and preamp off never had this before.Any suggestions would be great.Thanks in advance.
ebm
The water main should be iron, as it is an older house (1957). I’ve got the same pole type, but separate, ground for my large portable generator. Another discussion with my electrician. We’ve touched base and he will be coming over to check things out.
atmasphere
... you are far better off if the ground is tied to the water mains as is traditional. Stakes in the ground tend to be variable, and if the ground connection is indeed on the water mains, the stake in the ground should not be used at all unless all your water connections involve plastic pipes
I'm surprised to see Ralph state this. IMO, you are best served by complying with NEC and local codes. That usually requires stakes in the ground bonded to the ground in the service panel.

@cleeds 
I feel somewhat relieved to hear this, as I have had confidence in my electrician who has done some extensive work for me, including upgrading my electric service, installing a new panel with a built-in transfer switch for my generator along with the outdoor plug for it and ground, as well as the separate ground for the audio system.

As I am not knowledgeable in these matters, I must rely on others for their expertise. The electrician is tentatively scheduled for Monday afternoon.
IMO, you are best served by complying with NEC and local codes. That usually requires stakes in the ground bonded to the ground in the service panel.
@cleeds Actually I agree 100% with the code thing. Installing non-code grounds is asking for trouble! In some areas, the ground is handled by a stake, but that can be problematic so often metal water pipes are used instead as they can be a more reliable ground (this is code in my town). If a stake is the only ground connection, the problem can be that if its a dry environment, it won't really be a good ground.

I'm more concerned here about installations that I've heard of people doing where they ground a stake in the yard and then run their audio system grounds to it- a Bad Idea IMO/IME.
 Rep
1. The first thing I think of is a ground loop between cable TV and house ground.
Disconnect cable TV from the entire house, and re-test.
(the CATV ground should be entirely isolated from the house ground)
If noise goes away when CATV is disconnected:
In order to cure this, use a cable TV isolation transformer which is designed to stop audio buzz by isolating the cable ground from the house ground.
This type isolation transformer can be purchased ready made -or - you can make one by connecting 2X 75 ohm to 300 ohm antenna transformers, you connect the 300 ohm ends wire to wire. Then you connect your 75 ohm cable (in/out) to the coax ends of the transformers.
This will make an effective isolation transformer for about $10...You can make these out of Radio Shack antenna transformers.

2. Second thing that comes to mind is an ordinary ground loop.
Allow the preamp to use a 3 prong grounded plug. Then lift all other grounds (at the mains power plug) using adapters.
These power plug adapters (2 to 3 prong) are available at the hardware store.
You need 1 adapter for every piece of equipment that has a 3 prong plug.
Including: Lift TV, Lift sub woofer amp, etc...until all the grounds are lifted at the power plug, except 1.
This type of loop occurs when there are repeat grounds (more than 1 ground). The equipment is already grounded together using the audio cables...and the video cable.
Then, you ground everything to the mains power (3 prong plugs) and this makes the loop.
By lifting some or all of the grounds...you can stop this loop.