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[Gweedo]

Good morning all, I installed a new dash stereo and it sounds great however, I began having static through a front speaker when the unit is off with the fluorescent lights on.  If i turn of the light the static goes away.  The stereo jacks has a ground loop isolator in line.  I contacted Crutchfield and they suggested trying a direct ground, no change  then  suggested a power resistor or something similar on the battery line and if that didn't work to try on the power line.

Anyone experience this and if so what did you do.  I did notice one of the smaller fluorescent lights needs to be replaced, so I'm not certain if a ballast on the lights could cause this or what.  

 

Thnx

 

[timaz996]

The power resistor should do the trick. Get it at a stereo shop. I have so much noise in my coach I had to put them on my A/C units 12v power to keep them from short cycling.  

[Idoc57]

6 hours ago, Gweedo said:

Good morning all, I installed a new dash stereo and it sounds great however, I began having static through a front speaker when the unit is off with the fluorescent lights on.  If i turn of the light the static goes away.  The stereo jacks has a ground loop isolator in line.  I contacted Crutchfield and they suggested trying a direct ground, no change  then  suggested a power resistor or something similar on the battery line and if that didn't work to try on the power line.

Anyone experience this and if so what did you do.  I did notice one of the smaller fluorescent lights needs to be replaced, so I'm not certain if a ballast on the lights could cause this or what.  

 

Thnx

 

Or you could just convert the fixture to LED tubes.  If you just cut the offending ballast out and wire the LEDs direct to 12v, you could get rid of the feedback and have a better light fixture that uses less energy. 

Carey 

[Gweedo]

37 minutes ago, Idoc57 said:

Or you could just convert the fixture to LED tubes.  If you just cut the offending ballast out and wire the LEDs direct to 12v, you could get rid of the feedback and have a better light fixture that uses less energy. 

Carey 

Good idea, I’ve been thinking of doing that anyhow.  Thnx 

[MyronTruex]

I am curious what a "power resistor" is based on your usage. A resistor of any sort that I am aware of will drop voltage/current.

A choke, or coil will not drop the voltage but will "resist spikes" such as electrical noise from a light fixture.

Where did you get power and ground for your system? The further away from the batteries the more susceptible to electrical noise being picked up.

There are some powerful noise filters you would put nearest the stereo equipment. Some even filter the ground side but a good filter can help reduce things. 

With your stereo OFF, and electrical noise coming in, that indicates you have an amp that is still powered. The main power feed for example versus an ignition control line. In some cases you have to put all electrical feeds through the filter and then control that via a switch or relay.

This will take time to sort for sure but the recommendation to change to LED is by far the easiest solution. 

 

[Gweedo]

2 minutes ago, MyronTruex said:

I am curious what a "power resistor" is based on your usage. A resistor of any sort that I am aware of will drop voltage/current.

A choke, or coil will not drop the voltage but will "resist spikes" such as electrical noise from a light fixture.

Where did you get power and ground for your system? The further away from the batteries the more susceptible to electrical noise being picked up.

There are some powerful noise filters you would put nearest the stereo equipment. Some even filter the ground side but a good filter can help reduce things. 

With your stereo OFF, and electrical noise coming in, that indicates you have an amp that is still powered. The main power feed for example versus an ignition control line. In some cases you have to put all electrical feeds through the filter and then control that via a switch or relay.

This will take time to sort for sure but the recommendation to change to LED is by far the easiest solution. 

 

Thank you for the reply. I guess a filter is what I should have said.  There is an amp n if I remove the speaker jacks to the amp the noise goes away.   I don’t know if the amp is powered when the stereo is off but I’ll check it.   I still use the dash switch to turn off the stereo like the old stereo did 
 

I used the ground the old stereo used. I tried another direct chassis ground and it didn’t make a difference 

Crutchfield suggested a filter on the power lines n c what happens    But now I’m curious regarding the amp. 
 

I remember hearing a small buzzing nose in a speaker a few months ago but that went away.  
 

 

[Larry Laursen]

6 hours ago, timaz996 said:

The power resistor should do the trick. Get it at a stereo shop. I have so much noise in my coach I had to put them on my A/C units 12v power to keep them from short cycling.  

Tim I am wondering where you put the noise suppressor in you A/C control line and its size. I have a similar problem of short cycling.

[timaz996]

I stuffed them over the top of the AC ducting. They are about 3/4 of an inch thick and about 2 in. Square.

[Gweedo]

Okay so I went out to look and the amp power light is on!   I never notice because it sits below the shelf that hold the control box, in fact I didn’t even realize I had an amp until I started dealing Crutchfield.  
 

So we have owned the coach for 8 years which means that has been on 24/7, I’m surprised it is still alive!   I’m pretty mechanically inclined but know just the basics with electrical.   I guess I’ll have to figure out how the PO wired it in and solve this issue.  
 

I’ll attach a couple pics, let me know what you think if you know.

Thanks!!!!

[MyronTruex]

If things are or were not mounted then the ground part of the RCA jacks might have been touching some other ground which has the possibility of causing a ground loop hum. Bouncing around may have caused the touching to come and go.

Chasing electrical noise such as this can be really time consuming and frustrating. 

As things age and grounds become poor or modifications are made (new stereo), or things like fluorescent lights change their habits with aging components, you may have to attack it from a (fix the obvious first), method. You obviously know the lights are causing an issue. So take the plunge by gutting them and adding led strips. It is a easy project as things grow and your battery usage will drop dramatically if you boondock. 

[Gweedo]

Thanks for the advice, The RCA jacks that plug into the amp from the stereo has a ground loop isolator on it.  I'll check further into the amp light, it may just be showing it has power and it may not be on until the stereo is on.  Regarding the lights, that will be a project I'd like to do anyhow.  Good point looking to see if the wires/ground are making contact with something, I did straighten out a lot of the mess.

Thnx again!!

[Gweedo]

Problem solved.  So the fluorescent light causing the back feed has been replaced with led tubes. I Bypassed the ballasts. No more back feed    I replaced most of the smaller led lights as well.