Amp feedback
Thread Starter
Joined: Oct 2000
Posts: 4,440
Likes: 2
From: Surrey, BC, Canada
Amp feedback
So, I added a cheapo box and free amp to my car, sounds great (well, OK enough) when the car's off, but as soon as you start it the audio feedback is impossible to live with. Tone increases with RPM.
Where should I start to help eliminate the audio feedback?
Where should I start to help eliminate the audio feedback?
Honda-Tech Member
Joined: Oct 2007
Posts: 95
Likes: 0
From: omicron persei 8
Re: Amp feedback
Sounds like you're describing alternator whine. The two main culprits are bad grounds and electro-magnetic interference. First make sure you have a good ground--that's not too long--that connects to bare metal. Also, running your RCAs and your power wire parallel to each other causes this. If they're run on the same side of the car move one to the other.
Old Fart
Joined: May 2004
Posts: 26,173
Likes: 18
From: kelowna, bc, canada
Re: Amp feedback
What Mak Valley said, but another possibility is a "ground loop", as mentioned keep RCAs away from power lead/cable, or any power leads, best place to run RCAs is down center of car, shortest possible route or at the very least down to non power side of car, [most cars use the drivers side as the power side, leads for tail lights and so on],
Run power down the power side, or if RCAs are down the center, run the power down the same side cars batt. is on, again keeping leads as short as possible.
Also as mentioned, keep your amps ground lead as short as possible, of at least the same gauge as the power lead, and grounded directly to the cars floor pan, seatbeltbolts make good ground points.When you run your power lead you will also run a control/trigger lead, I always also run a "dump lead", 16ga lead connected to the chassis of the HU that may or may not be connected to the chassis of the amp to eliminate a ground loop.
You can test that by connecting a lead to the HU chassis and just running it over the seats to the amp and connecting to the amps chassis to see if the alt. whine is eliminated, if so then run it properly. 94
Run power down the power side, or if RCAs are down the center, run the power down the same side cars batt. is on, again keeping leads as short as possible.
Also as mentioned, keep your amps ground lead as short as possible, of at least the same gauge as the power lead, and grounded directly to the cars floor pan, seatbeltbolts make good ground points.When you run your power lead you will also run a control/trigger lead, I always also run a "dump lead", 16ga lead connected to the chassis of the HU that may or may not be connected to the chassis of the amp to eliminate a ground loop.
You can test that by connecting a lead to the HU chassis and just running it over the seats to the amp and connecting to the amps chassis to see if the alt. whine is eliminated, if so then run it properly. 94
Thread Starter
Joined: Oct 2000
Posts: 4,440
Likes: 2
From: Surrey, BC, Canada
Re: Amp feedback
Thanks for the feedback guys, I'll give those options a shot 
I kept the power and RCAs separated, RCA down the center and power down the side. I'll try ground loop elimination, a better ground on the amp, and making sure my power/grounds are in good condition, or at least eliminate that as a problem by adding extra wires to check if that's the issue (I rewired my engine harness and I have to admit honestly I did a crappy job).
I kept the power and RCAs separated, RCA down the center and power down the side. I'll try ground loop elimination, a better ground on the amp, and making sure my power/grounds are in good condition, or at least eliminate that as a problem by adding extra wires to check if that's the issue (I rewired my engine harness and I have to admit honestly I did a crappy job).
Thread
Thread Starter
Forum
Replies
Last Post