: New Amp and Sub garble radio signal?



JFensty
03-23-11, 08:08 PM
So I installed a Kicker 500w amp with a single 12. Ran 4ga power and ground and tied into orig. sub for signal using line out inverter. I figured the sub would not have full range this way but it was a quick fix until I can order a summing device as mentioned in other posts. I went to an open spot in fuse box, for remote power, under drivers side rear seat. I used a toggle for now. I wasn't comfortable splicing into any wires at this point. Amp toggled off = great radio reception. Amp toggled on (at any level) = garbled radio reception, even close stations.

Any ideas?
Thanks for the help.
Jerry

JFensty
03-23-11, 08:16 PM
Forgot to mention Cd sounds great and music through FM Modulator thru my droid sounds pretty good with little distortion, but plain radio is horrible at any level.

612WharfAvenue
03-23-11, 08:57 PM
Is the amp a class D by any chance? What model is it?

JFensty
03-23-11, 09:00 PM
Yes Class D Kicker 500.1.

612WharfAvenue
03-23-11, 09:43 PM
Class D's are known for throwing off some radio interference. Doesn't seem to be any clear cut solution. You could possibly try moving the amp elsewhere in the trunk. (Shame, I'm looking at throwing a new sub in soon and saving some money on the amp would have been nice.....)

JFensty
03-23-11, 09:57 PM
Right now its on pass side backed up to the seat. I'll move it tomorrow to see if it matters. Will have to relocate the ground.

perfect
03-23-11, 11:04 PM
Definitely make sure that you have a clean ground. I once saw a kid in a nice car try to mount his amp to a side panel in the trunk and one of the screws completely pierced the stock BOSE amplifier (he must have been seriously drilling to get this thing in there). I doubt you did this but make sure that you didn't mount the amp to anything accidentally or go over a cable.

How did you run your power cable? Through the driver side? What type of subs? Is it properly shielded?

JFensty
03-24-11, 07:30 AM
Ran the power cable down pass side thru a grommet under the dash that comes out right under the battery. Ground is to mounting bolt for bottom of top portion of rear seat. Properly shielded? Used a loc that sits nicely in on a metal tab right next to the sub. It is piggy backd of sub leads. 6ft rca to sub. sub in mounted on box for easy removal.

perfect
03-24-11, 09:52 AM
Some older subwoofers aren't shielded properly. They produce an EMI (electro-magnetic interference) that can interfere with the radio functionality.

Some things you can try to troubleshoot is to remove the sub from the box and leave the amplifier hooked up to the LOC. See if just having the amp on is causing your problems. Remove or add things incrementally to see if the problem goes away and to help narrow down which device might be causing the issues.

JFensty
03-24-11, 03:17 PM
Thanks for the info. I also noticed that with the sub turned up half way, while playing a cd, it caused the volume to go up suddenly as if the AVC on the radio was having issues. Then the volume would go down as well? WTF. I do have the stock amp and sub hooked up still.:hmm:

When I tried the sub today it worked well on two stations and the third went all garbled again...:banghead:

perfect
03-24-11, 03:32 PM
Unplug the stock sub. I have an LOC (David Navone - I recommend it in all of these threads) and I used the stock subwoofer wires to feed the LOC. I unplug the stock subwoofer. You may be creating some type of weird ground loop somehow.

JFensty
03-24-11, 06:08 PM
I'll check that. Moved the sub and amp all over the trunk, even unplugged the sub wires and still static and mess. Its wierd that it only bothers one or two stations and not even the same stations just random. I purchased a cheap loc from best buy, not sure if that would cause too much of this, just mess with overall performance.

Thanks for the help. I'll update later tonight if unplugging stock sub works.

BTW any one know which wire I can tap into on the stock amp for a remote wire. Possibly get the sub speaker wires before the amp as well?

JFensty
03-25-11, 07:02 PM
Unplugging the sub did nothing. Spoke with Kicker tech and he says that he has heard of the Class D amps causing some interference but"not that much". No answer for my issue either. Thanks Kicker...

JFensty
03-27-11, 08:00 PM
FYI.. I returned the Kicker for a Polk Audio Class AB amp and no interference whatsoever. Good Times!