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Assistance from Electronic Wizards!

Posted: Mon Sep 27, 2021 4:49 am
by Nicksacco
Hi All-
I hope you can provide me some insight on this strange audio problem.
I have installed:
--XM radio
--Garmin Nuvi
--2 channel audio mixer
--Bluetooth
--Ground loop isolator

All works well except when the Nuvi talks, the sound is distorted - barely audible.
This only happens if the Nuvi is running on bike power. If I unplug it's power cable - sound is no problem.

All electronics are operating on bike power through 12V to 5V converters except the mixer which is 12V.
I have run things straight from the battery also thinking somehow the bike's electronics had an affect - but makes no difference.
I've even run things from a totally separate battery.
I have included a block diagram to help.

My suspicion is that the Nuvi's output impedance is way off when on bike power but don't know if that is possible.

Does anyone out there have an idea??



Re: Assistance from Electronic Wizards!

Posted: Mon Sep 27, 2021 7:49 am
by DenverWinger
Ground loop from the common power supply.

I'd put another ground loop isolator between the Nuvi and the mixer. Should be able to run on bike power then.

Re: Assistance from Electronic Wizards!

Posted: Mon Sep 27, 2021 3:23 pm
by Nicksacco
I have another isolater so I'll give that a try!

Thanks for the idea.