Unwanted Stereo Speaker "noise" remedy by grounding ?

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powerplay

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Stereo Speakers with old amplifier and turntable is making "noise' when led lighting on a dimmer is on. Circuits come from the same subpanel in the basement but someone has told the person to eliminate the ground loop and isolate the "ground/bonding" by installing a rebar into the ground and connecting it and disconnecting the ground from the stereo plug. Is it possible that running a cable directly to the Main Panel only for the Stereo would possibly help eliminate the "noise' coming over the old speakers ?
 
powerplay said:
someone has told the person to eliminate the ground loop and isolate the "ground/bonding" by installing a rebar into the ground and connecting it and disconnecting the ground from the stereo plug.
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This advice is not only incorrect it is dangerous and probably will not solve the problem.
 
powerplay said:
Is it possible that running a cable directly to the Main Panel only for the Stereo would possibly help eliminate the "noise' coming over the old speakers ?
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You could try that out with a long extension cord and connecting the amplifier to other circuits in the house. Also possible that you are looking at this all wrong. How about replacing the dimmer with another type?

-Hal
 
There may be some truth here, but it mixed with a dangerous misunderstanding.

First the danger: connecting to an independent ground rod is dangerous. The purpose of the 'ground wire' is not the connection back to soil, but to provide a fault current path back to the neutral/ground bond at the panel. A separate ground rod removes this necessary fault current path; any fault to the chassis of the amplifier would energize the chassis without tripping a breaker.

On top of this, that separate ground rod becomes a path for soil currents to enter the equipment, pass through the house wiring, and exit via other ground electrodes.

Don't do it.

The tiny nugget of truth is that old audio equipment often attached the signal ground of the unbalanced signal cables to the chassis ground. You can have 'ground loops', meaning parallel paths in the wiring connected to the EGC, say if you have two pieces of equipment both with 'ground wires' and a grounded signal path between them. This can be a path for noise to enter the signal chain. Sometimes disconnecting the EGC can eliminate such noise.

But if the EGC is completely disconnected the safety issue is obvious...when the EGC is connected to a separate ground rod you get the illusion of safety when the setup is actually more dangerous than simply disconnecting the EGC.

Jonathan
 
powerplay said:
someone has told the person to eliminate the ground loop and isolate the "ground/bonding" by installing a rebar into the ground and connecting it and disconnecting the ground from the stereo plug.
Click to expand...
One thing you can do is temporarily plug it in via one of those two to three prong adapters, if that doesn't make the problem go away then you likely don't have a ground loop issue involving both speaker output and power supply.

If unit only has a two prong power cord then you also don't have that ground loop issue.
 
If I remember correctly old turn tables had an external bonding jumper that went to the chassis of the amplifier to limit noise. You can see the connection point on this old receiver.

IMG_20250409_093719064.jpg
 
Check speaker polarity
Keep speaker wire away from power lines

Remember that the main amp has huge transformers.. sometimes equipment stacked on top near the output trannys can generate noise. Try moving things around.

Dont try to iso a ground.. better to try a better (different) circuit..

Last is to check internal grounding in each unit... if the pots arent grounded to the bridge in my guitars, it will hum if my hand isnt on the strings- but this is a amp thats as loud as a jet...

I really like to rig a temp outlet at the panel and run a 100' to equipment for starts. (Or a washer outlet)
Things like dimmers, fans on low and such on the circuit MAY be a problem. Move the units away off the amp.

Is the amp solid state or tube?
 
Many years back I worked on a recording studio that had flown out an EE specialist to fix all the noise in a new system, they had all kinds of weird grounding, isolated ground receptacles etc.
He had us put in 60/120V transformer with a special loadcenter (2-pole breakers for 120V)
Each 120V receptacle in the studio had both legs 60V to ground, and that eliminated all the ground loops.
I think they make a hi-end product for audiophiles that does the same thing in a rack mount, basically an isolation transformer.
 
Thank you everyone for the feedback !

I had already indicated to the person before I posted, that a separate ground does create a potential shock hazard, especially with a rusty rebar which I thought interesting advice from an electrician.

I will pass the information along… thanks again !
 
tortuga said:
Many years back I worked on a recording studio that had flown out an EE specialist to fix all the noise in a new system, they had all kinds of weird grounding, isolated ground receptacles etc.
He had us put in 60/120V transformer with a special loadcenter (2-pole breakers for 120V)
Each 120V receptacle in the studio had both legs 60V to ground, and that eliminated all the ground loops.
I think they make a hi-end product for audiophiles that does the same thing in a rack mount, basically an isolation transformer.
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That is covered by Article 647, however its use is limited to commercial and industrial occupancies.
I am aware that some have installed such a power system in their houses.
 
Since every piece of A/V equipment has an isolation power-supply transformer, why would a 60-0-60v supply make any difference as compared to a typical 120-0v supply?
 
I would start by ensuring that the grounding jumper is installed between the turntable and the amp (if applicable). From Onkyo:

If the sound is distorted or sound quality is not good:


  • If your turntable has a built-in phono preamp, connect to other analog inputs such as LINE IN
  • If your turntable does not have a built-in phono preamp, connect a turntable to PHONO
  • Make sure that the ground wire is connected. Otherwise, it may produce an audible hum and noise
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LarryFine said:
Since every piece of A/V equipment has an isolation power-supply transformer, why would a 60-0-60v supply make any difference as compared to a typical 120-0v supply?
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I am no expert but the idea is the center tap is not used for anything other than equipment grounding so there is no electrical connection between a 'neutral' either utility neutral or the secondary neutral and either 120V Line.
Perhaps less amplitude = less pops and hisses.
I actually found an old thread where we discussed it this is the basic idea:
1744236469025.png

The rack mount system looks like this
1744236553323.png
 
My home theater system is dead quiet. I wired it normally, on a 50a, 120/240 feeder.

The yellow cable feeds a reed relay that controls a cube relay that controls a 4p contactor.

1744237164172.jpeg
1744237235096.jpeg
1744237592791.jpeg
 
kwired said:
Dead quiet doesn't seem all that desirable from something that is supposed to make sound. :)
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Oh, a wise guy! Seriously, it can cleanly play realistic concert level.

Total of 2,200w RMS:
Front left and right: 300w ea
Center, sides, and rears 200w ea
Stereo sub-woofers 300w ea
 
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Little Bill said:
How bout splaining a little about the how and why of this?
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Okie-dokie. The B&K preamp-processor in the pic has been replaced with a Fosgate FAP-T1+, which only has a 12v, 15ma trigger output. The only relay I could find with a coil current that low was a reed relay, which can not withstand the coil current of the 4p contactor. (DAMHIK)

Thus, I cascaded a relay with a coil current the reed relay's contacts could handle, and contacts capable of handling the contactor's coil current. I chose an ice-cube relay with 10a contacts. The two relays are on perf-board in a plastic package, in the panel with the contactor.
 
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As no ones lawyer i suggest taking two of these and putting on Slayer south of heaven... crooked cross, specifically, and then.. it just may clear up.
 
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