I get a nasty (high freq) buzz on the ground line. When I lift the ground connection, the system is quiet. This is on my pre amp. However any other source component that is grounded immediately introduces this buzz again -- as soon as I plug it in.
Also, this nasty buzz usually instantaneously goes away later at night, around midnight. Nothing in my house, as far as I can tell.
So can I install some type of a ground line filter? Is there such a thing? Recommendations?
thanks.
Herman
Also, this nasty buzz usually instantaneously goes away later at night, around midnight. Nothing in my house, as far as I can tell.
So can I install some type of a ground line filter? Is there such a thing? Recommendations?
thanks.
Herman
For each channel, lift the inputs' common ground bus from chassis or audio ground with a 10R resistor.
If the left and right commons are connected together, separate them and use the two resistors.
If the left and right commons are connected together, separate them and use the two resistors.
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Could be a neighbor last time I heard that somebody down the road was using a welder ,he phoned the power company and got his power transferred .
Some time later another neighbor started running an auto repair business from home and back came the problem.
Try Rayma,s suggestion first.
Some time later another neighbor started running an auto repair business from home and back came the problem.
Try Rayma,s suggestion first.
Kinda sounds like an old light dimmer. Is it the same time every night? Traffic signals, street lights, etc.
But why is the noise on the ground line? My house has its own copper ground rod. Could it be also connected to the main water pipe?
If that's the case then is there such a thing as a filter for the Ground line that would solve my issue?
If that's the case then is there such a thing as a filter for the Ground line that would solve my issue?
It is just a ground loop. Without details on the equipment, it is very difficult to explain how to prevent it.
I'll try to explain:
One side of my -- powered speakers
other side -- pre-amp and source equipment
Different outlets and different circuit breaker.
One side of my -- powered speakers
other side -- pre-amp and source equipment
Different outlets and different circuit breaker.
What is happening is that the loop formed by the mains and interconnects is creating a voltage just like the secondary of a transformer. Reduce the size of the loop and you will reduce the noise. Use one outlet for all equipment or use another way of breaking the loop.
Noviygera have you tested the ground/earth loop resistance of the sockets you use ?
Borrow a tester and check for resistance , this is a specialized meter used by electrical engineers/electricians.
It should show a very low ohm reading,if its an ohm or two you have an earth or earth return problem.
The old fashioned method in tube radio days requiring a good earth was to pour water over the earthing spike to reduce resistance in dry weather .
Having studied US earthing situations I agree that not all US homes ,especially rural have an adequate earth.
Borrow a tester and check for resistance , this is a specialized meter used by electrical engineers/electricians.
It should show a very low ohm reading,if its an ohm or two you have an earth or earth return problem.
The old fashioned method in tube radio days requiring a good earth was to pour water over the earthing spike to reduce resistance in dry weather .
Having studied US earthing situations I agree that not all US homes ,especially rural have an adequate earth.
A "ground loop" is better understood as a signal return or 0V loop, it is not related to the quality of the protective earth (PE) connection.
It certainly is related in the sense of a high resistance allows RF signals and noise to build up and puts the owner at risk of electric shock.
A build up in impedance hampers the hash being returned to ground earth in a local earth or the power station in a remote earth .
You are basing it being applied to audio circuits only I am basing it on real life electrical engineer.
I used to work for a telephone company and a business customer complained of their digital telephone system failing.
It was the processor that blew every time .
First the earth was tested and all connections re-terminated then a $10,000 digital mains tester was used and left on site.
It turned out after a week,s test that a piece of the companies own equipment was causing the problem.
A website for professional electrical engineers read-
A Practical Guide To Earth Resistance Testing
Read Rule 2---electrical noise.
A ground loop is not about RF signals and screening does not require an electrical connection to Earth.
There is no reason to believe that anything is wrong with the PE. You can't expect to connect grounded equipment to different outlets without using some kind of loop breaker.
The OP states in the very first post--
quote- "I get a nasty (high freq ) buzz on the ground line "----"any other component that is grounded --immediately introduces this buzz again ".
You are saying the mains ground is not at fault ??
Are you advising all equipment attached to his equipment should NOT be connected to the mains earth ?
Are you aware of UK electrical installations ( domestic premises -ring main ) regulations and BSI standards (UK ) ?
As you obviously don't believe me I refer you to the UK government regulations -
The Electricity Supply Regulations 1988
Go to Part 11-5
Notice as I have already said total resistance must not exceed ONE ohm.
Of course I know what loop resistance is but that wasn't the OP,s point ,it was the noise on the mains earth.
quote- "I get a nasty (high freq ) buzz on the ground line "----"any other component that is grounded --immediately introduces this buzz again ".
You are saying the mains ground is not at fault ??
Are you advising all equipment attached to his equipment should NOT be connected to the mains earth ?
Are you aware of UK electrical installations ( domestic premises -ring main ) regulations and BSI standards (UK ) ?
As you obviously don't believe me I refer you to the UK government regulations -
The Electricity Supply Regulations 1988
Go to Part 11-5
Notice as I have already said total resistance must not exceed ONE ohm.
Of course I know what loop resistance is but that wasn't the OP,s point ,it was the noise on the mains earth.
I presume his powered speakers are connected to mains earth and when he connects other earthed equipment the buzz appears. This suggests a "ground loop" to me, which behaves like an aerial.
Let's say the ground is 1 ohm between connected equipment and the induced voltage is 1 volt AC. You now have a 1 amp current flowing through the interconnects. Reduced the resistance and the current goes up.
Is it OK in this case to lift the ground on one side of the system?
I thought it was an external cause because it went away at around midnight...
I thought it was an external cause because it went away at around midnight...
It probably is an external problem. But it's still a ground loop. You have to break the loop to kill the buzz.
By ground loop, we mean that your system is tied to ground at more than one point. Between those 2 (or more) ground points there is a difference in voltage. That difference causes current to flow thru the ground circuits and wires of your system.
Break that loop and the current flow will stop.
Break that loop and the current flow will stop.