Hello.. Long time visitor to the site but this is my first post.
I just did full audio upgrade to my girlfriends new car and have a case of alternator noise coming in through the front components.
Amp is a Kicker ZX700.5 2010 or 2011 model. Components are Image Dynamics ctx-6.5cs. I have the amp bridged from 4 channels to 2 (and a single channel for the sub).
Now to the noise.. it varies with the engine speed, goes away when I disconnect the front RCA inputs from the amp. If I plug my phone into the amp RCA inputs I can play audio to the speakers with NO engine noise.. So I think the amp and speaker wires are ok.
I have tried:
new RCAs
routing the HU ground to the amp
routing the HU ground to the battery
routing the amp ground to the battery
doing a shield fix on the RCA cables (to ground them to the case of the HU)
unplugging the radio antenna
None of those have worked..
Things I still need to try:
Big 3 upgrade (ordering 0/1 gauge terminals today..)
Adding a capacitor (I have mixed feelings about this possibly working)
Testing a different amp ( I would need to buy one)
Any other tips or ideas? I have checked some other posts related to this issue and tried to do a RCA shield fix on the head unit.. From the RCA shield to the HU case I was getting 3 ohms, so I grounded them like I was told and now it reads 0.9 ohm but I still have the noise.
I just did full audio upgrade to my girlfriends new car and have a case of alternator noise coming in through the front components.
Amp is a Kicker ZX700.5 2010 or 2011 model. Components are Image Dynamics ctx-6.5cs. I have the amp bridged from 4 channels to 2 (and a single channel for the sub).
Now to the noise.. it varies with the engine speed, goes away when I disconnect the front RCA inputs from the amp. If I plug my phone into the amp RCA inputs I can play audio to the speakers with NO engine noise.. So I think the amp and speaker wires are ok.
I have tried:
new RCAs
routing the HU ground to the amp
routing the HU ground to the battery
routing the amp ground to the battery
doing a shield fix on the RCA cables (to ground them to the case of the HU)
unplugging the radio antenna
None of those have worked..
Things I still need to try:
Big 3 upgrade (ordering 0/1 gauge terminals today..)
Adding a capacitor (I have mixed feelings about this possibly working)
Testing a different amp ( I would need to buy one)
Any other tips or ideas? I have checked some other posts related to this issue and tried to do a RCA shield fix on the head unit.. From the RCA shield to the HU case I was getting 3 ohms, so I grounded them like I was told and now it reads 0.9 ohm but I still have the noise.
Invariably, alternator whine is due to a difference in ground potential between the source and amp. Your amp has differential inputs according to the manual, which makes this problem strange - usually such amps are immune.
Seems like you've addressed all the things most people would suggest. Relocating either the HU ground or amp ground is usually the solution. I have an extreme case with a Pioneer HU (notorious for bad RCA ground) in a car where the HU is mounted to metal and the ground is not in my control. The only solution I could find was a ground loop isolator.
Seems like you've addressed all the things most people would suggest. Relocating either the HU ground or amp ground is usually the solution. I have an extreme case with a Pioneer HU (notorious for bad RCA ground) in a car where the HU is mounted to metal and the ground is not in my control. The only solution I could find was a ground loop isolator.
I have read about RCA mute plugs.. I might give that a shot to see if it is the amp (although I dont think it is..)
Does a ground loop isolator have any drawbacks? do you lose sound quality?
Some people claim that they can hear a difference with a ground loop isolator but I think it depends on a lot of variables so you'd have to try it to see if it works well for you and your system.
How bad is the noise?
With no RCAs connected to the amp and the amp off, do you read anything less than 100 ohms between the amp ground and any of the individual speaker terminals?
If you disconnect all of the speakers from the amp and use a test speaker with a short length of wire, do you get engine noise on any of the 5 channels (head unit plugged into the amp)?
How bad is the noise?
With no RCAs connected to the amp and the amp off, do you read anything less than 100 ohms between the amp ground and any of the individual speaker terminals?
If you disconnect all of the speakers from the amp and use a test speaker with a short length of wire, do you get engine noise on any of the 5 channels (head unit plugged into the amp)?
Please disconnect the negative supply to your head unit , your problem should be sorted , provided you are not using the head units - chip amps to power front speakers or the like .
Suranjan
Suranjan
I can hear it if the volume is low or on mute.. if I am listening to it at medium to max volume I can not hear the noise most of the time.
I will test out the two things you listed there after work today.. thanks for the assistance.
So If I just disconnect the ground to the HU all together that would fix my problem? I do not have any speakers being powered by the HU, only front components and a sub being powered by the external amp.
By "negative supply" do you mean the ground wire?
Have you tried to move the rca cables around to try and find a quiet spot?
My alpine HU with zapco line drivers and balanced cable was picking up noise and I found that the short rca's that plug into the back of the deck from the line drivers were picking up noise from the wire harness behind the deck. Had to pull the deck, start the car and with the stereo on, find a home for these wires that did not pick up noise. You will want to do this as it drive me nuts to hear noise in the audio. 😎
My alpine HU with zapco line drivers and balanced cable was picking up noise and I found that the short rca's that plug into the back of the deck from the line drivers were picking up noise from the wire harness behind the deck. Had to pull the deck, start the car and with the stereo on, find a home for these wires that did not pick up noise. You will want to do this as it drive me nuts to hear noise in the audio. 😎
Hmm I will look into this also.. I had a set of RCAs running outside of the car to the amp to test the RCAs but I dont know if I made sure to keep it away from a harness.. Ill give this a shot.
I made a set of RCA mute plugs and connected them to the amp - no noise.. so that should rule out the amp. Also it is not the cross overs or the speakers/wiring because I took a extra full range speaker I had and connected a short run of wire to test each channel with the HU and RCAs connected - got noise in that speaker also. So I am looking at the HU as the problem at this point.
I have some more 0 gauge wire and a capacitor in the mail right now.. I will try a big 3 upgrade and installing a cap to quiet down the alternator this weekend.
Ill update soon.
I have some more 0 gauge wire and a capacitor in the mail right now.. I will try a big 3 upgrade and installing a cap to quiet down the alternator this weekend.
Ill update soon.
Here is something that did work, but I'm not sure if I like doing it this way..
When I tuned my amp I turned the EQ to flat (0s across the board) and turned the volume up to 27/35 and then increased my gains until I hit my 150v that I am sending to each component set. To get to this level I had to turn the gains up to about 7/10 and then tweeked my EQ down slightly. Never UP is what I was told.
Well today I turned the gains down until the noise went away. Then to get more volume I cranked up my EQs and guess what.. the noise is gone. So with the gains set on 3.5/10 the only way to get my power output is to turn the EQ settings up to about +9db on each EQ band and then adjust down from there.
Think this is ok? I dont know if cranking up the EQ like that is good for the sound quality or the amp.. then again I dont know if it will hurt anything.. might just be amping the signal before it gets to the amp.
I just got in a capacitor and some 0 gauge wire today so I am tempted to turn the gains back up and try a big 3 upgrade and a cap to see if that does anything.
What are your thoughts?
btw.. Gains = amp, volume = HU, EQ = HU
When I tuned my amp I turned the EQ to flat (0s across the board) and turned the volume up to 27/35 and then increased my gains until I hit my 150v that I am sending to each component set. To get to this level I had to turn the gains up to about 7/10 and then tweeked my EQ down slightly. Never UP is what I was told.
Well today I turned the gains down until the noise went away. Then to get more volume I cranked up my EQs and guess what.. the noise is gone. So with the gains set on 3.5/10 the only way to get my power output is to turn the EQ settings up to about +9db on each EQ band and then adjust down from there.
Think this is ok? I dont know if cranking up the EQ like that is good for the sound quality or the amp.. then again I dont know if it will hurt anything.. might just be amping the signal before it gets to the amp.
I just got in a capacitor and some 0 gauge wire today so I am tempted to turn the gains back up and try a big 3 upgrade and a cap to see if that does anything.
What are your thoughts?
btw.. Gains = amp, volume = HU, EQ = HU
150v to each component?
If it sounds OK, it's not doing any harm.
There is generally a fusible link or fuse between the battery and the alternator. If you upgrade and bypass that safety device, you could put the vehicle at risk for an electrical fire.
If it sounds OK, it's not doing any harm.
There is generally a fusible link or fuse between the battery and the alternator. If you upgrade and bypass that safety device, you could put the vehicle at risk for an electrical fire.
I was getting 150v @4 ohm to each component set when I tuned my amp and was getting this noise.. I have not had a chance to see what it is putting out now.
The issue is.. Ive always been told the right way to tune an amp is turn the HU up with the EQs down and increase the gain until I hit the target voltage. That = noise
The way I have gotten around the noise is to turn the gain down and the EQ up.. which I have been told is not the right way. So not sure what to do.
The issue is.. Ive always been told the right way to tune an amp is turn the HU up with the EQs down and increase the gain until I hit the target voltage. That = noise
The way I have gotten around the noise is to turn the gain down and the EQ up.. which I have been told is not the right way. So not sure what to do.
There is a problem with your meter if it read 150v AC at the speakers. The amp doesn't have enough rail voltage to produce 150v of AC.
The EQ is to correct for poor frequency response of the system as a whole. You only use it if you need to make corrections (most systems need corrections). The settings depend on where the corrections are needed.
JL amps are the only ones that I know of that have a target voltage. That's because they adjust the maximum output level depending on the load. This is not a feature of many other amps.
Even with JL amps, this generally doesn't work well for most users.
There is no foolproof way to set the gains for most systems because music varies so greatly. Ideally, you would set the gains so that the amplifiers are never driven into clipping. That requires huge amounts of power or a listener/user that doesn't require significant volume.
For most people, the gains are best set so that the amps don't clip on most music with the volume at about 75%. Again, this isn't fool-proof because increasing the bass boost or playing a track with a lot of bass could allow the amps to be driven to clipping at less than 75% of the volume.
When dealing with equipment that's not working properly (as it appears is the case with your head unit), you can't go by rules set for perfect systems.
The EQ is to correct for poor frequency response of the system as a whole. You only use it if you need to make corrections (most systems need corrections). The settings depend on where the corrections are needed.
JL amps are the only ones that I know of that have a target voltage. That's because they adjust the maximum output level depending on the load. This is not a feature of many other amps.
Even with JL amps, this generally doesn't work well for most users.
There is no foolproof way to set the gains for most systems because music varies so greatly. Ideally, you would set the gains so that the amplifiers are never driven into clipping. That requires huge amounts of power or a listener/user that doesn't require significant volume.
For most people, the gains are best set so that the amps don't clip on most music with the volume at about 75%. Again, this isn't fool-proof because increasing the bass boost or playing a track with a lot of bass could allow the amps to be driven to clipping at less than 75% of the volume.
When dealing with equipment that's not working properly (as it appears is the case with your head unit), you can't go by rules set for perfect systems.
You are correct.. I did not mean 150v.. I mean 150w.
"When dealing with equipment that's not working properly (as it appears is the case with your head unit), you can't go by rules set for perfect systems"
^ this is the key for me it sounds like.. I think I have two options at this point: 1. live with the system the way it is with my work around (EQ boost/lower gains) or 2. continue to look for the REAL solution and tune the amp the "normal" way.
Thanks for your insight PB.
"When dealing with equipment that's not working properly (as it appears is the case with your head unit), you can't go by rules set for perfect systems"
^ this is the key for me it sounds like.. I think I have two options at this point: 1. live with the system the way it is with my work around (EQ boost/lower gains) or 2. continue to look for the REAL solution and tune the amp the "normal" way.
Thanks for your insight PB.
When i run into headunits that have noisy RCA output, its usually a ground fuse on the headunit mainboard RCA plugs that pop.
as in, on the circuit board itself? I have soldering skills but I dont know how to read a board unless it is pretty obvious. Should I open up the case and see if I can spot any blown fuses on the board?
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