Voltage Reducer - Speaker Ground Loop

[Lee0]

Originally Posted by augiedoggy

You mean no engine... There most certainly is a motor..
technically "a motor" is electric and an engine is internal combustion powered.
https://www.kia.com/dm/discover-kia/...e-a-motor.html

electric motors or controllers can create electrical noise also.

fair enough

I was thinking more in regards to an alternator which usually is the culprit behind engine whine.

Never through an electric motor would impact in a similar way. Good point.

[Volt_Ampere]

The controller can make nasty electrical noise. It is chopping the current to the motor when it's running. It won't make noise when you are not driving though. A bad reducer can make noise too. They are also switching devices.

[augiedoggy]

Originally Posted by Volt_Ampere

The controller can make nasty electrical noise. It is chopping the current to the motor when it's running. It won't make noise when you are not driving though. A bad reducer can make noise too. They are also switching devices.

very true... both mosfet powered power switching devices.. (like the amp ironically)

My money is on that pile of ... I mean Pyle amp... try connecting it right to a 12v battery and see if you still get the noise.

[Lee0]

Originally Posted by augiedoggy

very true... both mosfet powered power switching devices.. (like the amp ironically)

My money is on that pile of ... I mean Pyle amp... try connecting it right to a 12v battery and see if you still get the noise.

That's my biggest hang up.... 6 x 8Vs.... so inconvenient.

[augiedoggy]

Originally Posted by Lee0

That's my biggest hang up.... 6 x 8Vs.... so inconvenient.

no car battery or jumper box handy?

[Lee0]

Originally Posted by augiedoggy

no car battery or jumper box handy?

good point. Just test the noise floor of the amp. I was thinking about your comment it in terms of narrowing down the source of the noise - not in terms of checking the noise floor of the amp.

That's a great idea.

[Lee0]

So I purchased 2 things to try.

1) Ground loop isolator 3.5mm aux
2) Input power "noise filter"


1) Ground Loop Isolator

This amp has an external volume control knob. I noticed that if I unplug this 3.5mm jack that connects the knob to the amp then the ground loop sound switched predominantly from one speaker to the other (2 speaker setup). If I hold the jack in place partway out, all of the ground loop noise disappears (but I have no volume control).

I plugged in the ground loop isolator between this connection - no significant improvement. Maybe a slight reduction at max volume setting (no music playing) - but overall no real improvement. I did try wrapping a wire around the jack bare metal to ground to common ground but made no difference.

2) Input Power noise filter

I wired this in between the the amp input power cable and the power distribution block. I noticed 2 things: a) it did not help with any of the ground loop sound, but b) I no longer have feedback/whine sound when turning on my LED pod lights. So big improvement for that, but not the base problem I was trying to solve.



All of this is with the cart on, but not moving so controller should be a non-issue.

Any other thoughts? I haven't tried a dedicated 12v battery yet since I'd have to pull out a lot of stuff to get to that wiring. Since I can get rid of the noise by playing with the 3.5mm volume input I doubt it's the amp noise floor though.

Big question - why would fiddling with the volume control knob 3.5mm jack solve the ground loop noise? How can I use that info to help my solution?

[Volt_Ampere]

External volume controls can be a big source of noise in a poorly designed amp. I would try shielding the cable to the external volume control and see if that helps. What kind of noise are you getting that you are calling a "ground loop"?

[radioman]

Suggest you try augidoggy's suggestion (post # 15) with temporary connection to a battery to power the amplifier.

[SolarRat]

Originally Posted by Volt_Ampere

External volume controls can be a big source of noise in a poorly designed amp. I would try shielding the cable to the external volume control and see if that helps. What kind of noise are you getting that you are calling a "ground loop"?

What he said^. That volume wire is acting like an antenna sending RF noise or whatever interference back to the amp. It's possible the wire just needs to be moved away from other wires/devices, or it needs to be better shielded (you can try tinfoil), or the shielding that is already in the coax needs to be grounded. I'd assume the shielding's ground ties in with the vehicle ground through the 3.5mm jack in most other applications. If you have an iron ferrite handy, you can try it on the vol. wire, but it's better to fix the cause.

And certainly try a separate 12v battery to rule out the converter.