Radio dropping out

[orangeman6]

I was hoping some of the electrical wizards could help me out.

During my rebuild, I built a headliner with a stereo console and a dome light. All of the wires for the stereo, including USB and aux in cables, run through the roof support bracket along with the wiring for the dome light. The roof support on the 2001 txt is 3/4", so getting all of this through was a pain. I ran it all up the driver's side as I wanted it all hidden and didn't want to drill through both sides of the front cowl. Because of the large amount of wires through the small space, I joined the grounds for the light and the stereo to the same wire. Also, the fm antenna comes from the roof and joins the rest of the wires going through the headliner and into the console.

Everything works well and the sound through the inputs is clean. However, I just noticed that if you turn the dome light on when the stereo is playing, the stereo sort of drops out. It still plays, but there is a very minor decrease in volume and a noticeable decrease in sound quality. I was listening to the fm at the time and didn't think to compare it to the other inputs. The dome light is led and shouldn't have a lot of draw.

My guess is that I'm getting electrical feedback from the power wires for both the light and stereo being together, but was curious as to what someone who has more knowledge thought about it. It's not a huge deal, as it's a tolerable loss in sound quality and the dome light is only used for a brief time. It would take a bit of work to re-pull any of the wiring, so if it's not hurting anything, it's something I can certainly deal with.

Thanks

http://www.buggiesgonewild.com/elect...txt-rehab.html

[Sergio]

The dome light is led

I think the issue is a "noisy" led driver on you lights interfering with the Radio.

Test it using an input other than AM/FM to verify it.

[JohnnieB]

In addition to what Sergio mentioned, if the sound volume and/or quality decrease on inputs other than AM/FM radio, you may have a ground loop caused by using a single B- wire for both the stereo and LED roof light.

Also, it appears that the stereo and roof light have power switches on the dash panel, which would make the power leads fairly long. Possibly the voltage drop on the power wiring is lowering the voltage input to the stereo to the ragged edge of the acceptable value and the additional current flow through the LED light takes it over the edge. (Low voltage to an audio amp, increases distortion)

What is the output wattage of the stereo? What gauge power wiring?

[orangeman6]

Thanks to both of you.

I won't be home for a couple of days, but will will check it with the USB and aux inputs when I get home.

JohnnieB, yes, there are switches on the dash that power the light and the stereo. The power wire to the stereo is 14g and the led is 16g. The stereo is 160w max. I can't remember what the rating was for the light. If it matters, there are relays to both. For what it's worth, I had it ~ 1/2 volume when I turned on the light. I turned it down a bit, but that didn't seem to change anything.

[cgtech]

Crummy led driver. Try any different dome light.

[BobBoyce]

Originally Posted by orangeman6

Thanks to both of you.

I won't be home for a couple of days, but will will check it with the USB and aux inputs when I get home.

JohnnieB, yes, there are switches on the dash that power the light and the stereo. The power wire to the stereo is 14g and the led is 16g. The stereo is 160w max. I can't remember what the rating was for the light. If it matters, there are relays to both. For what it's worth, I had it ~ 1/2 volume when I turned on the light. I turned it down a bit, but that didn't seem to change anything.

Minimum 12 guage, and preferred 10 guage on a 160 watt stereo B+ and ground for any run longer than 6 feet. Impulse currents are important when it comes to audio amps. If you have room in the overhead console, adding a 12V automotive ultracapacitor can help deliver those impulse currents.

Bob

[JohnnieB]

Originally Posted by BobBoyce

Minimum 12 guage, and preferred 10 guage on a 160 watt stereo B+ and ground for any run longer than 6 feet. Impulse currents are important when it comes to audio amps. If you have room in the overhead console, adding a 12V automotive ultracapacitor can help deliver those impulse currents.

Bob

I'd like to emphasize all electrical accessories on a golf cart are two wire systems and both the B+ and the B- (ground) wires should be the same gauge and ought to be the same length.

Personally, I believe 10ga is a bit on the thin side for feeding a 160W audio amplifier, but might be acceptable in this application if supplemented with a ultra-capacitor at the power input of the amp, since a golf cart acoustics are iffy at best.

About halfway down the website linked to below, is a chart for power wire(s) gauge vs RMS watts vs length. Some of the text on the page explains the need and reasoning for the wire gauges, the rest is advertising their stuff.
https://www.crutchfield.com/S-djgMa7...uge_chart.html

Using Crutchfield's formula, the 160W amps draws a max of about 23A, so they say 10ga is good up to about 16 feet, but I believe in overkill.

[orangeman6]

Super interesting responses, thanks again.

For what it's worth, the stereo is 160w max, not rms. And, that rating is based on 4x40. I am driving 4 speakers, but I don't think I've had it much past 50% volume, nor will I need to. I couldn't find the rms in the specs. I know it's usually easier to find that rating on separate amps, not sure why they're hiding it on the stereo specs. I'd be interested to know how much it's actually drawing. Either way, it does sound like I should have gone with bigger wire. A bit ironic in that I had just put a 500w rms amp in my kid's car and we ran 2g cable for that. I guess I should have given it a bit of thought.

The reducer I'm using is from Scotty B, and I'm pretty sure is 30 amp.

I'll have to look into the led driver and an ultra capacitor.

I know that in a typical stereo install, that includes an amp, you're never supposed to run anything next to the power wire. Due respect to everything above, but is it possible I'm just getting interference from the other power wire?

Thanks again for the education.

[Sergio]

I doubt You have a power problem, Your Radio likely draws less than 10 amps.

Those radios are designed to work as "plug-and-play" in existing automobile harness.

If the problem is indeed related to noisy in the power lines, it will not make any difference what input you are using.

If the problem is related to the harmonic frequencies generated by the LED driver in your dome light interfering with the tuning system of the AM/FM receiver, the problem will not exist in Aux/CD/USB/SDcard mode.

[orangeman6]

Originally Posted by Sergio

I doubt You have a power problem, Your Radio likely draws less than 10 amps.

Those radios are designed to work as "plug-and-play" in existing automobile harness.

If the problem is indeed related to noisy in the power lines, it will not make any difference what input you are using.

If the problem is related to the harmonic frequencies generated by the LED driver in your dome light interfering with the tuning system of the AM/FM receiver, the problem will not exist in Aux/CD/USB/SDcard mode.

Thanks Sergio. That makes perfect sense and gives me a great place to start.