So i have a small problem with my system.
Hope you guys can help (=
LIke a few days back I think i blew my preamp on my headunit (Pioneer DEH-P4800MP) I am going to take it in to the service center on friday but currently im driving it with an annoying noise in the front speakers. Before i go on here is some info on my system:
Pioneer DEH-P4800MP - HU
Alpine type-s 5x7's in front
Alpine type-s 6.5's in the back
Alpine type-r 12" sub
Alpine MRD-M605 powering the sub
the speakers are powered by an old alpine amp not sure what the model is.
So back to what happened. Today when i was driving i accelerated hard to get in a lane and all the sudden the whining in the front speakers got worse and i turned off my HU for a second to see if it was just temporary. when i turned on my HU the music was still whining and just as bad, but now my sub was not working. Checked the settings on the HU everything was okay. so when i got home i checked the fuses and wires all of those were all hooked up and no blown fuses. The turn-on signal for my subs amp comes from my 4ch. amp and that seems to be working fine. the sub amp on the other had wont turn on.
any ideas of whats wrong?
Replies (15)
markz on 05/9/2007 22:24:53
well there's a bunch of things that could be wrong..
first are there any indications that the sub amp is on at all? lights etc..
if it really isnt on check ur power wires make sure ur ground and power wires are well connected and in order.. and recheck those fuses sometimes they can be tricky.. check your remote wire make sure its sending a signal to the amp.. u say it comes from ur 4 ch im guessin u mean that u just extended the remote wire from the terminal on the 4 ch 2 your bass amp that shod be fine.. if all these things are ok then u most proably have an amp problem.
on the other hand if u are seeing signs of power on ur amp.. is the protection light on? if it is check the wires to ur sub there may be a short circuit there.
if the protection light isnt on check ur rca's make sure signal is going to the amp there may be a short there.
with regards to ur whining problem theres a couple things that can cause that if u wana get rid of it post a reply and let me kno.. i'll help.
30Hertz on 05/9/2007 22:49:07
If your sub amp isnt turning on, first check to make sure the REMote wire is getting power. Recheck your fuses and check EVERY fuse but I doubt thats your problem.
My bet...the REMote wire.
If your getting whining from acceleration, its probably an alternator whine.
How do you have your power ran? Is it right next to your RCAs? Always run the power on one side of the car and the RCAs on another. Try to limit the times each one has to come near, or cross eachother.
Let us know
trunkisloud on 05/9/2007 23:54:33
im not sure if it was swez or brownstone that said it doesnt matter if the power is ran next to the rca's. that its a myth or something.
30Hertz on 05/10/2007 00:53:47
Oh really? Go try it?
Its not a myth as far as my knowledge. =)
ttocs on 05/10/2007 09:51:58
that will cause noise, but not all of a sudden. I am more inclined to think your ground on that amp may be starting to go bad and its now grounding through the rca's. Remove the ground, clean the spot and then tighten it up again and see what happens.
swez on 05/10/2007 11:23:50
I have the same read here... REM, power and ground to the sub amp are the things to check first. If you lost any of these connections, this condition would be noted. (Especially if the amps are not bolted down and can move around when fast moves are made)
Secondly, you may want to reground the HU to a new location in the dash or floorpan. (Bare metal connections to a known good ground.
Trunk... It's always best to run power and RCA lines well apart from each other to prevent noise issues. Yes, I have seen a few ghetto rigs that broke that rule and got by, but it's not the best practice.
Swez
Pinch on 05/10/2007 13:35:36
Just a theory question here....if car audio systems are powered by esentially a DC loop (from one terminal on the battery to the other via all the stuff we connect to it) the entire car becomes a power wire right? Sure, it's the ground wire....but our 12V juice is still flowin through the chassis of the vehicle to the Neg term on the battery ultimately anyway, so running the RCAs anywhere near the chassis leaves them susceptible to AC noise pollution of some flavor. Thoughts?
/Always run my RCA and pwr wires 18+ inches apart & cross @ 90
//I'm just sayin..
///Scratchin my head here
Peace,
Pinch
swez on 05/10/2007 15:25:53
Technically, the whole metal structure is the "grounding plane" for all electrical gear in a car. I see your point and agree w/ the theory too. But as noted, we still recommend the RCA signal lines be separated from the Hot line off the battery to avoid ground loop noise and other noise issues.
I have a theory too... when power and grounds are close together with bundled RCA lines, there is some degree of inductance, resistive and capacitive energy in the couplings. (Stray electromagnetic fields are present) This is where the RCA's can get messed up as signal line levels are very low and the amplification factor from the amp is often very high. (Major gain structure increases) That's where the noise comes from.
1. Gain structure between HU/amps (often 100:1 ratios or more)
2. Proximity to power/ground lines and low signal RCA's
3. Ground loops (Power and grounds are not at the same reference levels and create noise unless we de-couple with a noise filtering transformer)
Make sense?
Swez
indoazn on 05/10/2007 15:26:46
The whining problem i can get fixed by a pioneer service center. At first i thought the whining was a bad ground but it seems as i may have messed up the preamp.
so i tried a dif. rca and it still didnt turn on. all the fuses are good, all that i know of, i checked the ones on the amp and the ones by the battery. are there any i should check on the car?
trunkisloud on 05/10/2007 19:33:56
you could also try this: it worked for me once....take a ground and ground the outside conductor on the rca's ....i dont care what anyone says it stopped the whining noise for me.. whether or not it damages the hu somehow in the longrun is beyond my knowledge...
swez on 05/10/2007 20:02:20
We have heard many reports of some Pioneer HU's that did not have good grounding at the RCA's and did as you mentioned and it fixed the problem. This may be one of them.
Swez
ttocs on 05/11/2007 10:42:55
trunkisloud-that is a perfectly fine way to test to see if there is a grounding issue, there is nothing wrong with that. If the ground on the amp goes bad the amp will seek ground normally through the chassis of the amp if it is mounted to the chassis of the car. If it isn't it will then seek ground through the rca's, THIS IS BAD and you can even set an rca on fire(not recommended but REALLY cool as long as it isn't your car). Rca's are not made for DC current, or ANY current in general........
As for running the wire away from the chassis you are correct. To be honest if you use good equipment, and make good connections, I don't care where you run the power wire(except for distributor and spark plug wires) you should not have noise. It is a common place for noise to leak in if there are not good connections. I have installed countless amps and I have ran many rca's next to power wires and I do not send stuff out the door with noise. If I am installing junk stuff then I certainly do go down opposit sides but with bad equipment you will often have nosie no matter what you do.
trunkisloud on 05/11/2007 14:53:07
thats it...i was ttocs who said it.....and im gonna have to agree with him..cause i usually run my wires together with no noise./
30Hertz on 05/11/2007 15:56:19
^^ Thats fine =) But I prefer to not do the same work twice so rather than taking a chance, i'll stick with running RCAs and power on opposite sides of the car =P
swez on 05/13/2007 06:17:43
Same here... I have seen it done by others. But have also had to rewire a few because of noise issues. Better to avoid doing the job twice.
If there are few options, bundle them and test as loose wires before one commits to hiding all the wires, only to find out there are major noise problems.
Swez
Hope you guys can help (=
LIke a few days back I think i blew my preamp on my headunit (Pioneer DEH-P4800MP) I am going to take it in to the service center on friday but currently im driving it with an annoying noise in the front speakers. Before i go on here is some info on my system:
Pioneer DEH-P4800MP - HU
Alpine type-s 5x7's in front
Alpine type-s 6.5's in the back
Alpine type-r 12" sub
Alpine MRD-M605 powering the sub
the speakers are powered by an old alpine amp not sure what the model is.
So back to what happened. Today when i was driving i accelerated hard to get in a lane and all the sudden the whining in the front speakers got worse and i turned off my HU for a second to see if it was just temporary. when i turned on my HU the music was still whining and just as bad, but now my sub was not working. Checked the settings on the HU everything was okay. so when i got home i checked the fuses and wires all of those were all hooked up and no blown fuses. The turn-on signal for my subs amp comes from my 4ch. amp and that seems to be working fine. the sub amp on the other had wont turn on.
any ideas of whats wrong?
Replies (15)
markz on 05/9/2007 22:24:53
well there's a bunch of things that could be wrong..
first are there any indications that the sub amp is on at all? lights etc..
if it really isnt on check ur power wires make sure ur ground and power wires are well connected and in order.. and recheck those fuses sometimes they can be tricky.. check your remote wire make sure its sending a signal to the amp.. u say it comes from ur 4 ch im guessin u mean that u just extended the remote wire from the terminal on the 4 ch 2 your bass amp that shod be fine.. if all these things are ok then u most proably have an amp problem.
on the other hand if u are seeing signs of power on ur amp.. is the protection light on? if it is check the wires to ur sub there may be a short circuit there.
if the protection light isnt on check ur rca's make sure signal is going to the amp there may be a short there.
with regards to ur whining problem theres a couple things that can cause that if u wana get rid of it post a reply and let me kno.. i'll help.
30Hertz on 05/9/2007 22:49:07
If your sub amp isnt turning on, first check to make sure the REMote wire is getting power. Recheck your fuses and check EVERY fuse but I doubt thats your problem.
My bet...the REMote wire.
If your getting whining from acceleration, its probably an alternator whine.
How do you have your power ran? Is it right next to your RCAs? Always run the power on one side of the car and the RCAs on another. Try to limit the times each one has to come near, or cross eachother.
Let us know
trunkisloud on 05/9/2007 23:54:33
im not sure if it was swez or brownstone that said it doesnt matter if the power is ran next to the rca's. that its a myth or something.
30Hertz on 05/10/2007 00:53:47
Oh really? Go try it?
Its not a myth as far as my knowledge. =)
ttocs on 05/10/2007 09:51:58
that will cause noise, but not all of a sudden. I am more inclined to think your ground on that amp may be starting to go bad and its now grounding through the rca's. Remove the ground, clean the spot and then tighten it up again and see what happens.
swez on 05/10/2007 11:23:50
I have the same read here... REM, power and ground to the sub amp are the things to check first. If you lost any of these connections, this condition would be noted. (Especially if the amps are not bolted down and can move around when fast moves are made)
Secondly, you may want to reground the HU to a new location in the dash or floorpan. (Bare metal connections to a known good ground.
Trunk... It's always best to run power and RCA lines well apart from each other to prevent noise issues. Yes, I have seen a few ghetto rigs that broke that rule and got by, but it's not the best practice.
Swez
Pinch on 05/10/2007 13:35:36
Just a theory question here....if car audio systems are powered by esentially a DC loop (from one terminal on the battery to the other via all the stuff we connect to it) the entire car becomes a power wire right? Sure, it's the ground wire....but our 12V juice is still flowin through the chassis of the vehicle to the Neg term on the battery ultimately anyway, so running the RCAs anywhere near the chassis leaves them susceptible to AC noise pollution of some flavor. Thoughts?
/Always run my RCA and pwr wires 18+ inches apart & cross @ 90
//I'm just sayin..
///Scratchin my head here
Peace,
Pinch
swez on 05/10/2007 15:25:53
Technically, the whole metal structure is the "grounding plane" for all electrical gear in a car. I see your point and agree w/ the theory too. But as noted, we still recommend the RCA signal lines be separated from the Hot line off the battery to avoid ground loop noise and other noise issues.
I have a theory too... when power and grounds are close together with bundled RCA lines, there is some degree of inductance, resistive and capacitive energy in the couplings. (Stray electromagnetic fields are present) This is where the RCA's can get messed up as signal line levels are very low and the amplification factor from the amp is often very high. (Major gain structure increases) That's where the noise comes from.
1. Gain structure between HU/amps (often 100:1 ratios or more)
2. Proximity to power/ground lines and low signal RCA's
3. Ground loops (Power and grounds are not at the same reference levels and create noise unless we de-couple with a noise filtering transformer)
Make sense?
Swez
indoazn on 05/10/2007 15:26:46
The whining problem i can get fixed by a pioneer service center. At first i thought the whining was a bad ground but it seems as i may have messed up the preamp.
so i tried a dif. rca and it still didnt turn on. all the fuses are good, all that i know of, i checked the ones on the amp and the ones by the battery. are there any i should check on the car?
trunkisloud on 05/10/2007 19:33:56
you could also try this: it worked for me once....take a ground and ground the outside conductor on the rca's ....i dont care what anyone says it stopped the whining noise for me.. whether or not it damages the hu somehow in the longrun is beyond my knowledge...
swez on 05/10/2007 20:02:20
We have heard many reports of some Pioneer HU's that did not have good grounding at the RCA's and did as you mentioned and it fixed the problem. This may be one of them.
Swez
ttocs on 05/11/2007 10:42:55
trunkisloud-that is a perfectly fine way to test to see if there is a grounding issue, there is nothing wrong with that. If the ground on the amp goes bad the amp will seek ground normally through the chassis of the amp if it is mounted to the chassis of the car. If it isn't it will then seek ground through the rca's, THIS IS BAD and you can even set an rca on fire(not recommended but REALLY cool as long as it isn't your car). Rca's are not made for DC current, or ANY current in general........
As for running the wire away from the chassis you are correct. To be honest if you use good equipment, and make good connections, I don't care where you run the power wire(except for distributor and spark plug wires) you should not have noise. It is a common place for noise to leak in if there are not good connections. I have installed countless amps and I have ran many rca's next to power wires and I do not send stuff out the door with noise. If I am installing junk stuff then I certainly do go down opposit sides but with bad equipment you will often have nosie no matter what you do.
trunkisloud on 05/11/2007 14:53:07
thats it...i was ttocs who said it.....and im gonna have to agree with him..cause i usually run my wires together with no noise./
30Hertz on 05/11/2007 15:56:19
^^ Thats fine =) But I prefer to not do the same work twice so rather than taking a chance, i'll stick with running RCAs and power on opposite sides of the car =P
swez on 05/13/2007 06:17:43
Same here... I have seen it done by others. But have also had to rewire a few because of noise issues. Better to avoid doing the job twice.
If there are few options, bundle them and test as loose wires before one commits to hiding all the wires, only to find out there are major noise problems.
Swez
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