ok, so as i had in my other thread, my bose speakers all pop whenever i change media sources, on/off/ and tracks on my HU. i am starting to think that my HU may be defective. I have come to this conclusion through the idea that because on/off pops are due to the amp turning before your source output is on and i was think that maybe my headunit isn't turning the amps off during a media change? does that make sense at all? my assumption is that the amps are supposed to stay on, so yeah, any thoughts?

or

the preamp outs are all 2 volts, could the bose amps be popping due to a higher voltage rca signal?

 

2 volts is somewhat low for the bose, and that wouldn't cause it. The bose amps do not have a soft turn on and off so they could very well pop as they are. Did you try re-grounding your head unit?

 

yes, the headunit has a solid ground now. its grounded 3 ways, once via the antenna, once via the case of the hu, and once via the ground wire from the harness, i don't think grounding is the issue lol

 

i talked to an installer today, the place that did my install and he said that the metra harness's with rca inputs tend to have alot of issues with alternator whine and popping noises and was possibly the reason why they installed the other harness on my car instead. So i am going to attempt to by pass the harnesses original rcas and tap in brand new ones instead

 

You need to ground the wire from the HU directly to the chassis, not through the metra harness.

 

the neg lead from the hu is grounded directly to the chassis and not through the metra harness. there is no negative lead on the metra harness for the headunit. there are 2 negative leads that are for the shielded cabling, that is it. everything is grounded as it should be.


i tested new rca's i cut up a 3 foot monster cable rca patch kit and spliced it to the harness, still have a popping noise. it has to be the amplifiers on the speakers at this point. my subs do not make a pop noise that i can hear like my speakers do, it has to be the amps

 

Sorry to bring up an old thread, did anyone ever figure this issue out?

 

Mine does this as well, did it with both my Pioneer 7600MP and Alpine 9856

 

mine pops too...im rerunning new speakers.....hope it will take care of it

 

i did solve the issue by using noise isolators, but thats it. I am assuming that there is an issue with the amps not receving a signal so then turn on and off making the popping noise. the noise isolator seems to have filtered it out and i hadnt had problems after that

 

I was told that this can be solved with a 100 ohm resistor (Radio Shack part # 271-1108) and 2200 Microfarad capacitor (Radio Shack part # 272-1048).

 

I read on one of the other forums that it has to do with the amp remote-turn-on lead. The lead from the stock head unit has lower voltage than the aftermarket head unit. This causes the popping from the speakers. There is some sort of regulator/resistor that can be bought at radio shack that will drop the voltage down to the stock h/u voltage. Give Crutchfield a call, they supplied me with this info.

 

Is the resistor & capacitor part #'s I provided above different from the ones you have installed?

 

The popping occurs because the Bose amp doesn't use standard signal input grounding to prevent electrically noisey operations like changing source or CD track being amped through the speakers. It uses a bizarre array of capacitors on the input stage instead. So when an aftermarket HU grounds the RCA signal when changing CD track it discharges these capacitors causing the popping. the only way round it is to either:
1. Use the speaker level input adapter which uses a hi to lo converter (line out converter) to take the speaker outputs from your Pioneer back down to RCA pre-out level. This compromises the sound quality and can introduce hiss and whine as the signal is being amped twice.
2. Solder a capacitor on the signal pin for all 4 channels as per the thread below. This isolates the grounding from the HU to the amp without compromising the sound to any noticeable degree.
http://www.audi-sport.net/vb/showthread.php?t=26307

 

I am in the middle of replacing my HU as well and have this POP sound too. I have tried this method and so far it does NOT work. In fact, the weird thing is that the amp won't come on until you bypass the resistor...I found this out by accident after I was troubleshooting this and couldn't get any sound, though every thing was on. So I don't know what to do, but I hate to put all this back together with that nasty popping sound that occurs.

 

I hooked up the resistor/capacitor the same way to my 98 Maxima w/ Bose. And I have the same problem as you: no amp power when the resistor is installed. I called Crutchfield, and he tech confirmed that the resistor/cap route is only for the pop noise when the HU is turned on. Since I have the noise when I switch sources, it's another problem altogether. He recommends trying to ground the HU to the stock amp ground location (inside the passenger kick panel) or just hook up through the speaker line outs from the HU.

Hope this is helpful for somebody.

 

Ok, I found a solution to this problem. I had the popping sound when changing between sources on my Kenwood Excelon headunit and a Metra 70-7550 wiring harness (Bose/Nissan Amp Integration harness).

I swapped the Metra 70-7550 for a Scosche OEA-4 wiring harness (Bose/Nissan Amp Integration harness) and all the popping sounds went away.

Buying capacitors and resistors and trying to re-ground the unit will not work. Change the harness to a Scosche OEA-4 harness and all should be good.

 

so basically you are saying it's not an inherent problem and just a problem with the Metra harness?



with that being said I am using a JVC headunit with a Metra 7550 harness and have zero popping what so ever.

 

It's nothing to do with the harness. The Metra harness is just a straight through adapter for a clean signal to the Bose amp from the HU RCA's. The Scosche OEA-4 is a speaker input adapter or hi-lo converter, gets rid of the popping but does not provide a clean signal to the amp as it's already been amplified, then reduced, then reamplified by the Bose amp. This can give you noticeable levels of hiss and even alternator whine on cheaper adapters. Some HU's suffer from the issue, some don't, it's all to do with how the HU mutes the RCA's when doing electrically noisy stuff like switching between CD & radio.