Sub Feeding Back
 

In the last month, something odd has happened with my sub.

It used to only be occassional, now it is the moment the key reaches the accessory position. This starts a mind melting feedback reverberation through my sub that continues exclusive of the headunit actually being on.

The issue is traveling through the power feed to the amp. Pretty standard fused 4 gauge.

The mystery to me in this is it started recently being a full time thing and used to be only here and there. Nothing was changed in the truck until today when I shortened the cable taking out about 6 extra feet.

Ideas on what would cause this or ways to fix? I cannot go to Moab without ghetto bass.

sounds liek a ground loop problem or possible RFI

is it a whining or really feedback? if its a whining its defintly RFI and it could be your wires or you could get one of those rfi guard thingies from radio shack

It is a loud howl independant of head unit being on.

It does not vary in pitch or volume, it starts as soon as the key goes to acc and stops when I turn the truck off.

What gets me is how nothing was modified, it just started.

How do I fix a "ground loop problem"?

make sure your ground on your amp did not come loose. Mine came super loose, when I checked the wire, it arched me like a motha. Check all your connections. Including the wiring on the sub, and the RCA cables. Even check the head unit sub woofer out rca cables. Try to elimiate as much problome causes as possible. I've also seen problomes where people run the power wire through the fire wall, and cut the protective coating on the power wire over time.

Where is the Remote amp turn on wire connected to. It should be the igniton wire behind the deck or an acessory one.

I can say that it is infact your amp. If you let it continue it will get much much worse and it may not be that the ground isn't snug....it may be that the paint hasn't been sanded out from under the lug like it should be or it could be loose. Also check all the grounds in your engine bay and that your battery is full of electrolyte.

now that I think about it check to make sure thatthe batt is grounded to the trucks body...if that ground goes loose and you are using a seatbelt lug you WILL have grounding issues.

It is not feedback in the pure sense. As soon as the key is in the acc position and without the head being on, the sub makes a loud hum that does not vary in frequency or volume.

I have traced and rechecked and re-rechecked the power, ground, etc.

Would anything be hurt grounding the amp back to the battery?

Right now it is grounded to the place near the jack under the driver's side rear seat with all the paint sanded away.

I have a road trip coming and do a big commute, so this is bumming me out.

The only reason I see fit for running your ground all the way to your battery is if you have to. I run bat caps and they requre it. Dont waste your time. Try chaning your ground

With a "ground loop isolator". Search for those words, or click:

https://www.yotatech.com/forums/f96/alternator-whine-44044/
https://www.yotatech.com/forums/f96/stereo-noise-through-acceleration-27217/
https://www.yotatech.com/forums/f2/eliminating-engine-noise-stereo-14385/

It occurs independant of RCA connection.

It occurs independant of the deck being on.

It does not vary with engine speed.

It occurs without the engine running.

The amp seems to be getting power when the head is off, so I am rerunning the trigger wire.

Grounding issues. I had the EXACT same thing happen...to the T. check all underhood grounds, there are 4.... Battery to chassis, battery to frame, battery to block, and intake plenum to chassis. You might also have a dead amp. Put the amp in someone else's car and see if it continues, might also want to try a proven working amp in your truck to see if it does it too...