Ground Loops

[Dela]

I've been dealing with speaker buzz/static - always intermittent (what isn't) Walter M6 pointed me in what I have to assume is the right direction, stating 'ground loop'

I have added a new reducer for speaker only, didn't solve. Have the RCA cable for sub running away from the power lines of speaker bars, didn't solve. Replaced 3.5 and RCA cables, didn't solve

I have to assume this ground loop concept is what's wrong..

but I have no idea how to locate a ground loop or where to start to remedy it.

Any help appreciated

thanks!

[JohnnieB]

Ground loops are difficult to find, but fairly easy to avoid.

The minus 12V wires of the two voltage reducers have to be tied together electrically as do all the "ground" (-12V) wires from all the 12V devices.

Personally, I'd use something like the ones shown on the attached brochure. Probably search for something about 4" or 6" long or so instead of 10", but the ones shown are the type. I'd isolate the ground bus from the cart's frame/body and whether I connect the bus bar to the battery pack's main negative terminal depends on whether the 12V outputs of the voltage regulators are isolated (floating) or referenced to the battery pack negative.

What it boils down to is that any resistance at all between the grounds (-12V) will allow a noise signal to be superimposed on the ground potential and be amplified by the electronics the same way noise on the +12V causes noise problems.

[Dela]

I actually don’t think I’ve grounded anything, just ran negative and positive 48 to reducer, how do I ground, and what devices need to be ground? They don’t have ground wires; is the negative wire a ground wire? What would be running to the ground bus bar you’re showing me?

Sorry, confused here

[JohnnieB]

Originally Posted by Dela

I actually don’t think I’ve grounded anything, just ran negative and positive 48 to reducer, how do I ground, and what devices need to be ground? They don’t have ground wires; is the negative wire a ground wire? What would be running to the ground bus bar you’re showing me?

Sorry, confused here

Sorry, I used "Ground" in quotes because it is a common, but technically incorrect, term to use when speaking about the return wire in the two wire ungrounded systems used in golf carts.

Car manufacturers and others use the frame and or metal body parts as the return path back to the battery to save money. Golf carts use a separate wire instead of the frame for electrical safety reasons.

Having two voltage regulators complicates things a bit, but only on the +12V side of things. Don't tie the +12V outputs together or the two regulators will continuously try to correct any differences in the +12V from each, and there will be differences. I'd try to power all the audio stuff from the same voltage regulator if possible.

All the -12V return wires should be connected to a heavy distribution bar, something akin to the +12V distribution bar without the fuses. The trick is to reduce the resistance between all of the return wires and the -12V output of the voltage reducer(s) to 0.000000000Ω, or less. (That is impossible, but that is the goal)

[Dela]

Thanks for your help here - I am using this fuse block with negative bar (?)

Is this sufficient for what you are explaining? Or do I need to run all 12- lines to a different bar?

Also - please note the double negative lines on the fuse block - I have a line running from the 48- pack to the fuse panel block and then running a line from the reducer to the block. I'm assuming this is wrong, and may be causing the loop after reading what you're telling me.

[orangeman6]

Deka, I don’t know if any of this will help, in addition to the info from Johnnieb, but some interesting reading.

https://www.crutchfield.com/S-wioHwK...ion_guide.html

[JohnnieB]

Originally Posted by Dela

Thanks for your help here - I am using this fuse block with negative bar (?)

1. Is this sufficient for what you are explaining? Or do I need to run all 12- lines to a different bar?

2. Also - please note the double negative lines on the fuse block - I have a line running from the 48- pack to the fuse panel block and then running a line from the reducer to the block. I'm assuming this is wrong, and may be causing the loop after reading what you're telling me.

1. That ought to do the trick.

2. Try it with and without the connection to the 48V battery pack. Also the -12V wire to the voltage reducer ought to be heavier. It is carrying the -12V return from all seven +12V devices. 10Ga or 12Ga would be better.

What is the Make/Model of the reducer.

[Sergio]

Are You sure the interference is power related?

Are You running any other accessories, specially LEDs with a wide voltage range?

[Dela]

Originally Posted by JohnnieB

1. That ought to do the trick.

2. Try it with and without the connection to the 48V battery pack. Also the -12V wire to the voltage reducer ought to be heavier. It is carrying the -12V return from all seven +12V devices. 10Ga or 12Ga would be better.

What is the Make/Model of the reducer.

Thanks Johnnie!

[Dela]

Originally Posted by Sergio

Are You sure the interference is power related?

Are You running any other accessories, specially LEDs with a wide voltage range?

I'm really not sure, no - I just added a ground loop isolator and so far, no more buzz - here's to hoping.. Too bad I could have done this for $9 vs $90, but lesson learned and maybe it will help others.

I have other accessories, yes. AC system, wifi router, ipad charger, usb port for phone, led lights, sub woofer and the two sound bars

The router and ipad are on constant charge

AC and USB and sub on key switch on one reducer

Both speaker bars on a separate reducer on key switch as well


If this isolator doesn't work, I'll report back