Noise from alternator and through speakers

[DUK13Y]

Hey guys, I recently installed a 4ch amp to power my door speakers and a 2ch amp to power my subs. This was done in my VYII with the factory headunit using the high level input for the 4ch amp, and a LOC for the 2ch amp. Now I have a noise coming from my speakers that is a high frequency constant tone when i put the key into one click before start-up. This then turns into alternator whine when the car is started.

However, I also have the same noise coming direct from the alternator which you can hear with the bonnet lifted, or if you just listen closely. I've done a bit of research and the closest similar case is from a guy who said it was the alternators regulator or diode cluster that had died and it was the charge escaping through the broken components.

My car also sometimes wont start, one of the symptoms this other guy had too. Won't even crank the starter motor. Just turn the key and nothing. All other electricals work when this happens though. Dad said it might be the relay not kicking in.

How should I tackle this and try to solve it? Cause I can get rid of the noise by putting the 4ch amp onto the LPF, however in doing this, I lose all mid-range, so the only speakers working really are the tweeters and the subs. Sounds awful. So would like to get this sorted asap. Thanks guys.

[HoldenOnn]

Only thing that I can suggest is for the noise. I have had friends who have had this issue after amp installs. The fix for them was to turn the gain down on the amplifier. It didn't effect the sound quality of the stereo, but it did get rid of the horrible buzzing that your experiencing.

[ephect]

The buzzing is generally an earth issue, maybe clean the earth point for the amp and see if that fixes it

[kiwicon]

The buzzing is generally an earth issue, maybe clean the earth point for the amp and see if that fixes it

+1 on the bad earth

[Antsmash]

I get the same noise when I plug my iPod charger in whilst I'm playing music through the head-deck (Aux in Mod). But only when it's charging.

[fordy227]

I had the exact same problem when I had my sub installed in my vt an it was faulty relays take it to the auto electrician

[ephect]

I had the exact same problem when I had my sub installed in my vt an it was faulty relays take it to the auto electrician

Did u add ur own relay in or it was by chance one of the existing relays was faulty? That's a rarity, if it's faulty what ever was attached to that relay should have been giving u problems

[DUK13Y]

Where would be the ideal earthing point? And i've heard mixed report of earthing all at one point for all amps and also earthing each amp at its own grounding point.

I'd take it to an auto sparky right away but don't want to pay someone else to do what might be a mundane job. Being an electrical apprentice myself and my dad being an electrician for 40 years, we don't like taking electrical problems to others. However we will if 100% necessary. I'm going to try and source a replacement alternator and see what that does. Also try and redo the grounding points and redo the entire stereo wiring.

[ephect]

I can't remember exactly, but earth both devices on the one point. Wire brush the mount point. I'm not 100% sure on the best mount point on the vy. This should be the fix u will need, only source an alternator after ur wire testing.

[sweefu]

Is your power cable running near your RCA interconnects / LOC or anything of that nature? That can induce alternator whine. Did you sand back your amplifier earth(s) to bare metal? Do you have 1 common earth or two separate earths?

[DUK13Y]

Ok i just changed my earth to 8G mounted onto the baby seat harness bolt with the area sanded back to bare metal and still the noise is there. It's like a replica of the noise that you can hear at the alternator. Only hooked up the 4ch amp as that was the one giving me the trouble just to test if the noise decreased or made any difference. Power cable isn't that close to my LOC or the high-inputs of the amp and made no difference when I moved the distro block away completely. I'm starting to think there is more of a problem with the alternator itself as the sound is identical from both my speakers and the alternator. It's driving me nuts only running tweeters and subs. Sounds horrible.

[ari666]

crap + leads can cause that buzz too. not just an earth.

i over-earth my impala subs. had 6G running from the battery all the way to the amp AND earthed off the boot floor. buzzed and ticked when then indicators were going. i bridged an extra power wire to it and it went away.

wire, then wire some more.

[TMM]

Two things to try:

1. Unplug your RCAs from the amp, drive the car. Ideally get some RCA plugs and short the terminals together, then plug them into the amp inputs.
If the noise goes away then you know you are getting noise from your RCA cables or LOCs - relocate them away from any power cables or other electrical wires. Ideally locate your LOCs close-ish to the amp, but not right next to it or near power wires. The high level (speaker wires) signal is much less susceptible to noise then low level (RCA). Therefore it's better to have a long run of speaker wire, then the loc and a short run of low level to the amp.

2. Disconnect the remote wire from the amp (so it stays off), drive the car. If the noise persists then you know you are getting noise from your speaker wires. Reroute the speaker wires away from any power cables.

[DUK13Y]

Ok so I tried to double ground by grounding at both the baby harness bolt and a seat belt bolt, both sanded to bare metal using 8G wire and it made absolutely zero difference. When I was first looking for a grounding point it at least got noticeably different depending on where I grounded it. Now with two solid ground, no change at all is noticeable.

I also noticed a slight hum from the alternator while the car was running. I've read that when an alternator is dying it hums because of a crap bearing or something similar and that it squeals when not running due to dead diodes. Sounding like my alternator is goneskies. I don't know what else it could be. I've double grounded with improved grounding points, moved all wiring away from power sources, installed a noise suppressor, tried using both LOC's and high input to see if one was at fault. No change is made.

Unless I can get more suggestions of what the problem could be, I'm going to try and source a replacement alternator. Dad seems to think the alternator is the key source of the fault so fixing that should be the first step.

[DUK13Y]

Two things to try:

1. Unplug your RCAs from the amp, drive the car. Ideally get some RCA plugs and short the terminals together, then plug them into the amp inputs.
If the noise goes away then you know you are getting noise from your RCA cables or LOCs - relocate them away from any power cables or other electrical wires. Ideally locate your LOCs close-ish to the amp, but not right next to it or near power wires. The high level (speaker wires) signal is much less susceptible to noise then low level (RCA). Therefore it's better to have a long run of speaker wire, then the loc and a short run of low level to the amp.

2. Disconnect the remote wire from the amp (so it stays off), drive the car. If the noise persists then you know you are getting noise from your speaker wires. Reroute the speaker wires away from any power cables.

I've tried moving the LOC's around in hope that it was something simple like interference like that but unfortunately not.

I will try the remote wire trick though. See what happens.

[FstStig]

You will need a Noise filter. It will filter out any interference caused by the Alternator etc

[DUK13Y]

Did what TMM said and disconnected the remote wire and noise disappeared completely. So did my speakers however but that was expected seeing as my amp wasn't turned on. So now that it's not interference, what could it be? It must be picking up a signal from somewhere