Voltage Reducer - Speaker Ground Loop

[Lee0]

Hey Guys,

Back again! For those of you keeping count this is my 3rd "I'm stumped please help" thread in a week. Must be that kids fall sports are done so "upgrade fever" has struck.

In my other thread I mentioned accidentally melting down my voltage reducer during an amp install. It was a brain fart moment, but happened when I was trying to troubleshoot an audio ground loop noise.

I have a small audio amp being powered by a voltage reducer (48v - 12v). Prior to blowing it all up, I had some pretty significant ground loop noise. Being as the voltage reducer I'm using separates 12v & 48v grounds, does anyone have any suggestions or experience on how to troubleshoot?

[jasonojordan]

Where did you run the ground for the amplifier to? The power distribution block or the chassis?

Is the amplifier the one you linked in your melting experience? In my experience the Pyle brand stuff is pretty budget level stuff and the humming is prob due to poor engineering in that amplifier itself.

You could try a ground loop transformer and see if that helps clean your power feeding the amplifier from the voltage reducer.

https://www.amazon.com/Isolator-Supp.../dp/B07S8VKG99

[Lee0]

Originally Posted by jasonojordan

Where did you run the ground for the amplifier to? The power distribution block or the chassis?

Is the amplifier the one you linked in your melting experience? In my experience the Pyle brand stuff is pretty budget level stuff and the humming is prob due to poor engineering in that amplifier itself.

You could try a ground loop transformer and see if that helps clean your power feeding the amplifier from the voltage reducer.

https://www.amazon.com/Isolator-Supp.../dp/B07S8VKG99

Yes, that cheap Pyle amp. I'm fine with some noise since low expectations from a cheap amp. But this was a pretty loud hum. Like could hear clearly from 10-15ft away loud.

Originally only ground amp to the distr. block, distr. block back to reducer, reducer to battery. No chassis ground. I don't have anything grounded to chassis currently? Doesn't it need a path back to battery (somewhere on the chassis to be ground to a batt)? I guess I could run a wire from the ground block to the chassis and then ground the amp directly to the chassis. Might clean it up a bit - I'll give it try that when I'm back up and running.

Not a bad idea on the isolator. Usually try to avoid things like that since its a bandaid/mask for root cause - but can't think of a clean fix.

Not looking for audiophile perfection - keeping expectations reasonable - anything not audible <5ft is kind of my target.

[jayhrc51]

What is the signal source that's feeding the amp, a radio, bluetooth, mini-phono to RCA plugged into a phone? If you're using RCA connectors, check those by unplugging to see if the noise stops. That'll tell you if it's source related. It could be a bad cable. Or it could just be the amp is noisy.

[Lee0]

Originally Posted by jayhrc51

What is the signal source that's feeding the amp, a radio, bluetooth, mini-phono to RCA plugged into a phone? If you're using RCA connectors, check those by unplugging to see if the noise stops. That'll tell you if it's source related. It could be a bad cable. Or it could just be the amp is noisy.

Bluetooth. No headunit installed.

It does have an external plug in volume control and aux input. But was using bluetooth when getting the ground loop noise. Haven't tried aux.

Pic of cheap amp attached.

[augiedoggy]

The pyle stuff has very poor noise isolation... I have a brand new pyle amp sitting in my garage cabinet because the whine was soo loud in a car with proper installation. You may want to consider a noise filtering capacitor. Does the noise come on which the motor and vary in pitch depending on rpm? or is it always there even when the car sits still?

[jayhrc51]

I went a similar route in order to use bluetooth. There aren't many mini bluetooth amps out there and you'll need to step up in price a little to get a different one, but it's worth the expense in my opinion. Pyle products have a history of poor quality. I would not be surprised if you get rid of that amp, you would also get rid of that noise.

[Lee0]

Originally Posted by augiedoggy

The pyle stuff has very poor noise isolation... I have a brand new pyle amp sitting in my garage cabinet because the whine was soo loud in a car with proper installation. You may want to consider a noise filtering capacitor. Does the noise come on which the motor and vary in pitch depending on rpm? or is it always there even when the car sits still?

Electric cart so no motor whine.

[Lee0]

Originally Posted by jayhrc51

I went a similar route in order to use bluetooth. There aren't many mini bluetooth amps out there and you'll need to step up in price a little to get a different one, but it's worth the expense in my opinion. Pyle products have a history of poor quality. I would not be surprised if you get rid of that amp, you would also get rid of that noise.

yeah, went into it knowing it was a cheap near-term solution. Will likely upgrade later.

But this loop noise is loud enough i'd almost be concerned it would damage the speakers potentially; not volume wise, but harshness.

[augiedoggy]

Originally Posted by Lee0

Electric cart so no motor whine.

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.