I just finished installing an Audiobahn A6000T 4-channel amp ,and Sony 250 watt amp for the subs, running off of a Pionner DEHP670MP. Everything sounded fine, then all of a sudden I started getting a terrible whine noise. With the car off it's more like a humming noise and I can hear the CD player spinning the CD. When the car is on the whining is so loud I can't listen to anything.
I checked and rechecked all the grounds for the amp and tested several spots for the HU, nothing helps. The RCA cables are no where near the power wire for the amps. Changing the input sensitivity on the amp does nothing, unless it's all the way down, but then whats the use of having an amp? I connected my Ipod to the amp and it sounds fine, I think it might be my HU.
I don't understand where this noise is coming from. It sounds like I can hear the cd spinning in the cd player, and if i use anything electrical I get a popping noise through the speakers. When I roll the windows down, I can hear the motor through all the speakers. This is getting ridiculous, one day it sounded perfect, then all of a sudden i get this problem. Please HELP!
Replies (9)
ttocs on 06/13/2006 17:17:40
what are the gains set at? Do you have everything grounded at one point?
UKinstaller on 06/13/2006 19:27:53
try grounding the outputs of the head unit. pioneers are notorious for bad outputs.
does the amp have high level inputs?? if it does, try using those, too. do away w/ the rca's all together.
-UK
MrBrownstone on 06/13/2006 19:50:56
sounds like a gain control issue. If you set the amplifier gains to the lowest settings, does the whine go away.
Test
turn your radio to the lowest setting. Listen to system with the car running. Is there whining sound? If so, vary your amplifier's gain control from the lowest to the highest settings.
Whine is almost always caused by amplification devices picking up noise from your car's electrical system. When your amp (or EQ) gain controls are set to their most sensitive settings, they most likely are picking up the noise.
Try the above and give us some feedback. The solution is either replacing the amp...turning down the amp gain control, and/or buying a line driver to get more signal into the amplifier.
In most cases, it's not hard to identify the problem
Victor on 06/13/2006 19:54:27
Yes I agree with UK, Pioneers are definitely notorious for bad outputs..
Try Grounding the RCA outs to the chassis.. and also the HU frame/body to the chassis..
Also the gains...as Mr.B suggests..
JohnnyChabes on 06/13/2006 23:11:29
ok...if i set the gain all the way down, i still get the noise. I'm not exactly sure how i could ground the outputs for the head unit, do i just rip apart the RCA cable or something? And do i have to ground every channel this way? If it makes any difference i have 6 channels leaving the HU. Two for the front, two rear, which go into the A600T. And two for the sub, which go into the Sony.
And one more thing i forgot to mention. When I turn the system on with everything in place, almost every time, the protection light on the Sony amp turns on and the amp shuts off. But if I unplugg the front and rear channels from the 4-channel amp I have no problem with the Sony amp. How could the RCA's affect the amp this way?
swez on 06/14/2006 09:58:14
Hummm, this is an interesting nest of bees...
Does the noise problem go away when the engine is off and you run the system off the ACC key position?
Most of these issues are common when a "reference ground" is lost or fails. This problem is commonly called a "ground loop".
1. The HU should be grounded to the floor pan or firewall (bare metal)
2. All amps need to be grounded properly to floor pan as well (bare metal connection too)
Grounding the RCA's means: The outer claw of the RCA connectors are grounded to the HU chassis. Normally, this is done inside the HU as part of the internal circuit connections. However, on some troublesome HU's, an additional external ground helps knock out the noise.
This usually means connecting an extra ground wire from the rear chassis grounding screw, to a bare metal connection on the floor pan or firewall. (NOT THE WIRING HARNESS)
FYI: The RCA outputs are rated at 2.2 volts. That means your amp gains can be set to about 2.0 volts or slightly higher for a good gain match to amps. If splitters are used, you may need to drop amp gain settings below 2.0 volt setting to get best results.
Swez
JohnnyChabes on 06/14/2006 10:07:47
I went out this morning and tried grounding the RCA's to the HU. That did the trick, all noise is gone. Thanks everyone for your help!!!!!! This problem was driving me nuts.
swez on 06/14/2006 10:39:34
Good job JC!!!
Looks like this HU is primarily made for non-US markets. I take it you are not from the USA? Regardless, welcome to CK!
Swez
UKinstaller on 06/15/2006 08:52:58
mmmmm hmmmm.
-UK
I checked and rechecked all the grounds for the amp and tested several spots for the HU, nothing helps. The RCA cables are no where near the power wire for the amps. Changing the input sensitivity on the amp does nothing, unless it's all the way down, but then whats the use of having an amp? I connected my Ipod to the amp and it sounds fine, I think it might be my HU.
I don't understand where this noise is coming from. It sounds like I can hear the cd spinning in the cd player, and if i use anything electrical I get a popping noise through the speakers. When I roll the windows down, I can hear the motor through all the speakers. This is getting ridiculous, one day it sounded perfect, then all of a sudden i get this problem. Please HELP!
Replies (9)
ttocs on 06/13/2006 17:17:40
what are the gains set at? Do you have everything grounded at one point?
UKinstaller on 06/13/2006 19:27:53
try grounding the outputs of the head unit. pioneers are notorious for bad outputs.
does the amp have high level inputs?? if it does, try using those, too. do away w/ the rca's all together.
-UK
MrBrownstone on 06/13/2006 19:50:56
sounds like a gain control issue. If you set the amplifier gains to the lowest settings, does the whine go away.
Test
turn your radio to the lowest setting. Listen to system with the car running. Is there whining sound? If so, vary your amplifier's gain control from the lowest to the highest settings.
Whine is almost always caused by amplification devices picking up noise from your car's electrical system. When your amp (or EQ) gain controls are set to their most sensitive settings, they most likely are picking up the noise.
Try the above and give us some feedback. The solution is either replacing the amp...turning down the amp gain control, and/or buying a line driver to get more signal into the amplifier.
In most cases, it's not hard to identify the problem
Victor on 06/13/2006 19:54:27
Yes I agree with UK, Pioneers are definitely notorious for bad outputs..
Try Grounding the RCA outs to the chassis.. and also the HU frame/body to the chassis..
Also the gains...as Mr.B suggests..
JohnnyChabes on 06/13/2006 23:11:29
ok...if i set the gain all the way down, i still get the noise. I'm not exactly sure how i could ground the outputs for the head unit, do i just rip apart the RCA cable or something? And do i have to ground every channel this way? If it makes any difference i have 6 channels leaving the HU. Two for the front, two rear, which go into the A600T. And two for the sub, which go into the Sony.
And one more thing i forgot to mention. When I turn the system on with everything in place, almost every time, the protection light on the Sony amp turns on and the amp shuts off. But if I unplugg the front and rear channels from the 4-channel amp I have no problem with the Sony amp. How could the RCA's affect the amp this way?
swez on 06/14/2006 09:58:14
Hummm, this is an interesting nest of bees...
Does the noise problem go away when the engine is off and you run the system off the ACC key position?
Most of these issues are common when a "reference ground" is lost or fails. This problem is commonly called a "ground loop".
1. The HU should be grounded to the floor pan or firewall (bare metal)
2. All amps need to be grounded properly to floor pan as well (bare metal connection too)
Grounding the RCA's means: The outer claw of the RCA connectors are grounded to the HU chassis. Normally, this is done inside the HU as part of the internal circuit connections. However, on some troublesome HU's, an additional external ground helps knock out the noise.
This usually means connecting an extra ground wire from the rear chassis grounding screw, to a bare metal connection on the floor pan or firewall. (NOT THE WIRING HARNESS)
FYI: The RCA outputs are rated at 2.2 volts. That means your amp gains can be set to about 2.0 volts or slightly higher for a good gain match to amps. If splitters are used, you may need to drop amp gain settings below 2.0 volt setting to get best results.
Swez
JohnnyChabes on 06/14/2006 10:07:47
I went out this morning and tried grounding the RCA's to the HU. That did the trick, all noise is gone. Thanks everyone for your help!!!!!! This problem was driving me nuts.
swez on 06/14/2006 10:39:34
Good job JC!!!
Looks like this HU is primarily made for non-US markets. I take it you are not from the USA? Regardless, welcome to CK!
Swez
UKinstaller on 06/15/2006 08:52:58
mmmmm hmmmm.
-UK
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