Alternator Noise in mids/highs

[leonfowler]

I think I have checked almost everything and I'm at my wits end. I have an annoying wine coming from my door speakers. I have checked and rechecked all the ground, upgraded the RCA, re tuned and nothing makes it stop. Its only there when the truck is running and get higher with more rpms. Goes away when RCA is unplugged (tested at deck and amp same results). System rundown: 1993 Chevy 1500, Pioneer Deck, RF Prime 250x4 w/ RF Prime 6.5 Components, also 2 RF Prime 250x1's and 2 RF Prime R2-D4 10'S. Battery to fuse block is 1/0 cca, fuse block to amps is 4g cca. Same sizes on grounds. Ground block is grounded to seat bolt. Big 3 has been done and power and signal are as far apart as possible. Truck had no functioning radio when I got it. Installed the deck found 1 working speaker other 3 were dead, and 4 went out sort time later. This noise is driving me nuts, I can't listen at low volume due to the noise. Subs have no issues that I can hear only the components.

try turning your deck up higher and setting you gains lower at the amp..try 80% at the deck and re adjust ur gains..also a deck with 4 volt preouts will help u as well..

[Kyblack76]

I think I have checked almost everything and I'm at my wits end. I have an annoying wine coming from my door speakers. I have checked and rechecked all the ground, upgraded the RCA, re tuned and nothing makes it stop. Its only there when the truck is running and get higher with more rpms. Goes away when RCA is unplugged (tested at deck and amp same results). System rundown: 1993 Chevy 1500, Pioneer Deck, RF Prime 250x4 w/ RF Prime 6.5 Components, also 2 RF Prime 250x1's and 2 RF Prime R2-D4 10'S. Battery to fuse block is 1/0 cca, fuse block to amps is 4g cca. Same sizes on grounds. Ground block is grounded to seat bolt. Big 3 has been done and power and signal are as far apart as possible. Truck had no functioning radio when I got it. Installed the deck found 1 working speaker other 3 were dead, and 4 went out sort time later. This noise is driving me nuts, I can't listen at low volume due to the noise. Subs have no issues that I can hear only the components.

try turning your deck up higher and setting you gains lower at the amp..try 80% at the deck and re adjust ur gains..also a deck with 4 volt preouts will help u as well..

Doing that, hides the final fix. Your or his deck, may clip higher.

[mnrookie]

Try using a 3.5mm to rca cable and connect your phone or ipod to the amp directly. See if that eliminates it. I'm guessing it's a blown pico fuse. You could also try grounding your rca's to the deck case like so

[never knows best]

sounds to me like a ground loop.

[Amart88]

[never knows best]

copy/paste expination-

Alternator Whine

To me, alternator whine is the most annoying form of noise. For those of you who are lucky enough never to have been exposed to alternator whine, it sounds like a miniature siren that rises in pitch with the speed of the engine. Alternator whine is almost always caused by a ground loop. The following steps will aid you in locating and correcting a ground loop problem.

1. Verify that all levels are set properly.
2. With the system turned off, unplug the RCA inputs to the amplifier.
3. Start the vehicle and turn the system on. If the noise is gone go to step 8. If the noise is still present, it is coming from the amp or the speaker wiring. Continue.
4. Turn the system off and disconnect the speaker harness.
5. Start the engine and verify that no noise is present. In a few rare instances, I have actually heard speakers reproduce noise without being connected to an amplifier. This noise was being induced by power cables that were very close to the speaker wire. If you do have this type of noise, reroute the appropriate speaker lead and go to step 3.
6. With the speaker harness still disconnected, check to make sure there are no shorts between the speaker leads and the chassis of the vehicle. A shorted negative speaker lead will create a ground loop by establishing a second audio ground reference point. If you do have a short, trace the wire out and repair it then go to step 3.
7. With the RCA inputs and speaker harness still disconnected from the amplifier, use your VOM to measure from the shield of the RCA jacks on the amp to the chassis of the vehicle. This reading should not be a direct short (100 ohms or more is acceptable.) If this reading does indicate a direct short, you might have a defective amp and should contact the manufacturer for verification.(Note that there are a few "inexpensive" amps or boosters on the market that have their audio ground and electrical ground commoned internally. For units of this type, the information in this article will be of very little value.)
8. If youve made it here, you know that the amplifier and speaker wiring are okay.
9. Connect the accessories in front of the amp (crossovers, equalizers, etc.) one at a time and check for alternator whine. When each device is tested, there should be nothing plugged into the input of that device. In this way, we will work toward the source unit piece by piece. Be sure to turn the system power off before connecting or disconnecting any cables or accessories.
10. Repeat step 9 until all accessories have been tested.
11. If a particular accessory is causing noise, try disconnecting its power ground wire. Go to step 9.
12. Now its time to connect the source unit. Do that now and test for noise.
13. If noise is present, try unplugging the antenna. If the noise goes away, you will need to use an antenna isolator. This little gismo opens the shield wire of the coax to eliminate the ground loop caused by the ground at the antenna.
14. If you still have noise, try connecting the source units ground wire in another location, preferably as close to the source unit as possible.
15. Does the noise vary in amplitude when you adjust the volume control? If it does, the problem is probably power line related and not a ground loop. If this is the case, run the source units B+ (yellow) wire directly to the positive terminal of the battery. If this doesnt do the trick, you will probably have to use a power line filter on the source units B+ (Yel) and Ignition (Red) wires.

[EKCASA]

Try using a 3.5mm to rca cable and connect your phone or ipod to the amp directly. See if that eliminates it. I'm guessing it's a blown pico fuse. You could also try grounding your rca's to the deck case like so

Thanks, tried this but no luck. The noise goes away when I unplug the rca from the deck, I'm thinking the deck is just old and worn out.

[EKCASA]

copy/paste expination-

only thing in front of the amp is the deck. The noise goes away if I disconnect the deck or turn volume to 0. Does not get worse with high volume but does with more rpms. Thanks for the walk through.

Alternator Whine

To me, alternator whine is the most annoying form of noise. For those of you who are lucky enough never to have been exposed to alternator whine, it sounds like a miniature siren that rises in pitch with the speed of the engine. Alternator whine is almost always caused by a ground loop. The following steps will aid you in locating and correcting a ground loop problem.

• Verify that all levels are set properly.
• With the system turned off, unplug the RCA inputs to the amplifier.
• Start the vehicle and turn the system on. If the noise is gone go to step 8. If the noise is still present, it is coming from the amp or the speaker wiring. Continue.
• Turn the system off and disconnect the speaker harness.
• Start the engine and verify that no noise is present. In a few rare instances, I have actually heard speakers reproduce noise without being connected to an amplifier. This noise was being induced by power cables that were very close to the speaker wire. If you do have this type of noise, reroute the appropriate speaker lead and go to step 3.
• With the speaker harness still disconnected, check to make sure there are no shorts between the speaker leads and the chassis of the vehicle. A shorted negative speaker lead will create a ground loop by establishing a second audio ground reference point. If you do have a short, trace the wire out and repair it then go to step 3.
• With the RCA inputs and speaker harness still disconnected from the amplifier, use your VOM to measure from the shield of the RCA jacks on the amp to the chassis of the vehicle. This reading should not be a direct short (100 ohms or more is acceptable.) If this reading does indicate a direct short, you might have a defective amp and should contact the manufacturer for verification.(Note that there are a few "inexpensive" amps or boosters on the market that have their audio ground and electrical ground commoned internally. For units of this type, the information in this article will be of very little value.)
• If youve made it here, you know that the amplifier and speaker wiring are okay.
• Connect the accessories in front of the amp (crossovers, equalizers, etc.) one at a time and check for alternator whine. When each device is tested, there should be nothing plugged into the input of that device. In this way, we will work toward the source unit piece by piece. Be sure to turn the system power off before connecting or disconnecting any cables or accessories.
• Repeat step 9 until all accessories have been tested.
• If a particular accessory is causing noise, try disconnecting its power ground wire. Go to step 9.
• Now its time to connect the source unit. Do that now and test for noise.
• If noise is present, try unplugging the antenna. If the noise goes away, you will need to use an antenna isolator. This little gismo opens the shield wire of the coax to eliminate the ground loop caused by the ground at the antenna.
• If you still have noise, try connecting the source units ground wire in another location, preferably as close to the source unit as possible.
• Does the noise vary in amplitude when you adjust the volume control? If it does, the problem is probably power line related and not a ground loop. If this is the case, run the source units B+ (yellow) wire directly to the positive terminal of the battery. If this doesnt do the trick, you will probably have to use a power line filter on the source units B+ (Yel) and Ignition (Red) wires.

Thanks I tried most of this. Hopefully I will get to the bottom of it.

[BoomZoom808]

same issue I have. I will let you know when i figure out how to reduce or remove completely.

Did you every try bypassing the factory ground and go direct to frame?

[Bump4life]

same issue I have. I will let you know when i figure out how to reduce or remove completely.

Did you every try bypassing the factory ground and go direct to frame?

yes. i have a direct run to the same ground as my amps and processor