Please help with alternator whine in speakers and popping noise when powering on/off.

[aod]

Hello all,

My audio project for my 1990 ZR1 has been a nightmare. I sent my speakers to Dr. Don to have him fix the amps in them because they were dead. Excellent service and turn around time, by the way. Next I wanted to upgrade the head unit so I went with a Pioneer Appradio 2 so I can also hook my Android phone to the head unit and get hands free bluetooth in the car along with navigation from my phone and pandora for tunes. The idea was to not cut or mess with any factory wiring and retain the original bose speakers with the upgraded head unit. I ordered the unit through Crutchfield and they included a harness that let me do just that. This is the harness:
http://www.crutchfield.com/p_120701857/Metra-GM-Factory-Integration-Adapter.html?tp=3486

Everything went together fairly well, all except the 14' of cable in a run where you really only need about 2 or 3 feet. Anyhow, I get alternator noise and some ignition noise along with loud pops when powering the head unit on and off. I've tried everything Crutchfield has told me: Grounding to a good ground - as a test I even ran the ground directly to the battery. This did not help. They also suggested cutting the wire ties off the harness and fanning the RCA cables away from the power wires, which is probably something they should have done in the first place. Anyhow, this did not help the issue either. As a test I would remove one RCA cable from the head unit one at a time and when I did, the alternator whine in that corresponding speaker actually got louder. To make certain that it wasn't the speakers, amps, or something wrong with the car I removed the Metra wiring harness and re-connected the factory wiring, then connected the stock head unit back into the system. There is no noise whatsoever when I do that, so that limits the problem to either the new head unit or the harness. Crutchfield is sending me out a new head unit and harness which should arrive in a couple of days. Somehow I am not convinced this is going to solve the problem. If it doesn't, does anyone else have any ideas on what to try? I'm guessing I'll probably end up with RCA ground loop isolator filters but I'm already at capacity inside the dash even after cutting the old support for the bose head unit out of there.

Thank you much for any help in advance!

[scottfab]

Looks like they offer a lifetime support.
I'd ask for a wiring diagram.
Since Bose uses a differential drive circuit
I'd be interested in how they try to accomplish
the connections.
Also if you can scan in or post a picture of the installation
instructions maybe one of us can spot something.

[aod]

I'll check to see if there were any instructions that came with the harness. It is fairly simple though. The RCA plugs plug into the corresponding RCA jacks on the head unit and the rest of the wire colors match up to the wire colors on the head unit. This harness bypasses the module in the dash (I guess that is a tuner module?) that is right under the glove compartment. But, if there are any instructions I'll take a picture or something and post it up.

Thanks!

Edit: Scratch that. Here is a .pdf to the instructions that was provided in the link I posted above:
http://a248.e.akamai.net/pix.crutchfield.com/Manuals/120/120701857.PDF

[scottfab]

Ok first goal is to find the source of noise not to install.
Therefore tie all three harness grounds together and ground
to the chassis ground of the box under the glove box.
Make the other front and rear audio connections without the ant.
Next tie the two power wires together (switched and constant on) and leave the ant power wire disconnected. Now take those two that are tied together and run them
straight to the battery hot side.
Check for noise using iPod or USB not radio.

NOTE this wiring will cause the radio to be on all the time. That's fine remember we're just testing.

If you still hear the noise try running a groud directly from the chassis on you new radio to ground.

[aod]

Ok first goal is to find the source of noise not to install.
Therefore tie all three harness grounds together and ground
to the chassis ground of the box under the glove box.
Make the other front and rear audio connections without the ant.
Next tie the two power wires together (switched and constant on) and leave the ant power wire disconnected. Now take those two that are tied together and run them
straight to the battery hot side.
Check for noise using iPod or USB not radio.

NOTE this wiring will cause the radio to be on all the time. That's fine remember we're just testing.

If you still hear the noise try running a groud directly from the chassis on you new radio to ground.

Thanks. I've tried all of these things except connecting both power wires together and running power directly from the battery. Could the factory power leads be causing the noise? I will certainly give that a try if the new head unit and new harness don't solve this.

[scottfab]

Thanks. I've tried all of these things except connecting both power wires together and running power directly from the battery. Could the factory power leads be causing the noise? I will certainly give that a try if the new head unit and new harness don't solve this.

Good luck with that.

[secondchance]

Aod,

Lets start withe the alternator whine. What you need is a 3300 microfaraday axial capacitor.
http://www.radioshack.com/product/index.jsp?productId=12424820 (http://www.radioshack.com/product/index.jsp?productId=12424820)

This capacitor is wired on the output of the alternator and grounded on to the side of the alternator (one of the alt. housing bolt). Make sure arrow on the side of the capacitor is from the pos. to ground (current flow). 90% sure this will take out the whine.

As for the popping when the head unit is turned on or off, you need ground loop isolators.
http://www.ebay.com/itm/3-5MM-GROUND-LOOP-ISOLATOR-KILLS-HUM-NOISE-AUDIO-FILTER-SNI-1-3-5-US-SELLER-/170811154632?pt=US_Car_Audio_Video_Interconnect_Ca bles&hash=item27c52360c8

To use this you will have to use Metra harness since you need RCA connection to splice this in. Also, you will need two ground loop isolators since your head unit has right/left for front and right/left channels for rear speakers. You do not need to ground out (two brown wires) isolators. Ground loop isolators are sort of miniture transformers and will allow low level audio signal from the head unit to your amps and yet not allow electronic noise generated between various ground points on your chasis and mistaking temporay voltage difference when the car is turned on or off as an audio signal.

I recently installed a Pioneer AVIC Z140BH and spliced into OEM Bose amp/speakers and experienced on/off pop. Ground loop isolators took care of this annoying noise.

Try these two remedies and post the result. If any other noise remains we can address it.

Good luck!

[scottfab]

Aod,

Lets start withe the alternator whine. What you need is a 3300 microfaraday axial capacitor.
http://www.radioshack.com/product/index.jsp?productId=12424820 (http://www.radioshack.com/product/index.jsp?productId=12424820)

This capacitor is wired on the output of the alternator and grounded on to the side of the alternator (one of the alt. housing bolt). Make sure arrow on the side of the capacitor is from the pos. to ground (current flow). 90% sure this will take out the whine.



Not sure what a "microfaraday" is. I was taught in college the unit of measure is "farad" so "microfarad" would be the correct term.
Also this part would be inappropriate I sorry to say in two respects.
1. It is an electrolytic and as such does not do well against fast ripple. What you want is ceramic and not anywhere near that high a value is needed. The stock wiring from GM will have a large diameter wire to the battery. The battery acts as a HUGE cap. If the use of a cap here helps then there is a major problem with either the battery connection, wire itself or the connection at the alternator.
2. The temp range of that cap will not survive on the alternator. It's max is 185 deg F. It get's much hotter then that near the V. Full specs are here:
http://www.sourceresearch.com/nte/nte-pdf.cfm?pdfpage=nev-neh.pdf

As for "ground loop isolators" otherwise known as signal transformers this may help but .... I'd be pissed at the harness manufacturer if this is so since they claim to be compatible with Bose. I do think this is the case here and is why I asked for a wiring diagram from the vendor to be posted. Generally I think this is a fly-by-night vendor just scooping up $ for a piece of crap. I'm waiting the hear what a new head unit and harness does. (as was posted)

[aod]

Not sure what a "microfaraday" is. I was taught in college the unit of measure is "farad" so "microfarad" would be the correct term.
Also this part would be inappropriate I sorry to say in two respects.
1. It is an electrolytic and as such does not do well against fast ripple. What you want is ceramic and not anywhere near that high a value is needed. The stock wiring from GM will have a large diameter wire to the battery. The battery acts as a HUGE cap. If the use of a cap here helps then there is a major problem with either the battery connection, wire itself or the connection at the alternator.
2. The temp range of that cap will not survive on the alternator. It's max is 185 deg F. It get's much hotter then that near the V. Full specs are here:
http://www.sourceresearch.com/nte/nte-pdf.cfm?pdfpage=nev-neh.pdf

As for "ground loop isolators" otherwise known as signal transformers this may help but .... I'd be pissed at the harness manufacturer if this is so since they claim to be compatible with Bose. I do think this is the case here and is why I asked for a wiring diagram from the vendor to be posted. Generally I think this is a fly-by-night vendor just scooping up $ for a piece of crap. I'm waiting the hear what a new head unit and harness does. (as was posted)

I just got off the phone with Metra and they don't really have any wiring diagrams to give out but he was willing to go over the pinouts with me. Not having the harness in front of me, that wouldn't have done much good. He did say that there are no electronics in that harness and the harness is cables only. He said the popping is common when trying to integrate with Bose systems and ground loop isolators should get rid of the popping. He said he has not run into an instance of alternator whine and so there actually might be a problem with the head unit or the harness. They have not arrived yet, hopefully they will arrive today so I have the weekend to work on it. I'll update here when I find out if it is the head unit or harness causing the noise.

Thanks again for the ideas and help!

[scottfab]

I just got off the phone with Metra and they don't really have any wiring diagrams to give out but he was willing to go over the pinouts with me. Not having the harness in front of me, that wouldn't have done much good. He did say that there are no electronics in that harness and the harness is cables only. He said the popping is common when trying to integrate with Bose systems and ground loop isolators should get rid of the popping. He said he has not run into an instance of alternator whine and so there actually might be a problem with the head unit or the harness. They have not arrived yet, hopefully they will arrive today so I have the weekend to work on it. I'll update here when I find out if it is the head unit or harness causing the noise.

Thanks again for the ideas and help!


Sure sounds like a fly-by-night operation. If the new setup does the same thing as the old and you still want to proceed, you're going to have to design the thing yourself. This means more than just isolating the differential drive circuit but possibly isolating some grounds too. The other alternative I've heard others do is dump the Bose and go with a whole new system. It's sure on my list of possible improvements. I just hate having to mess with stock dash looks.

[aod]

Sure sounds like a fly-by-night operation. If the new setup does the same thing as the old and you still want to proceed, you're going to have to design the thing yourself. This means more than just isolating the differential drive circuit but possibly isolating some grounds too. The other alternative I've heard others do is dump the Bose and go with a whole new system. It's sure on my list of possible improvements. I just hate having to mess with stock dash looks.

Strange thing is that Metra isn't a fly-by-night outfit. They make a lot of different things and have been around for quite a while. Unfortunately, it just seems like Bose systems don't like to play nicely with anything else which isn't too surprising I guess. I would like to keep it as factory as possible other than updating the head unit so I'm going to do my best to make this path work. Especially since I've already spent $320 getting all the amps in the speaker pods repaired. And to be honest, the factory speakers do sound quite good.

[secondchance]

Scottfab,
I stand corrected. It has been a while since I graduated - yes, it is microfarad.
My first enclounter w/ alternator while was in 1980 when I installed Mitsubishi electronic head unit w/ 4 channel, 100 W Mitsubishi amp in my first Corvette - 1979 L48 car w/ mighty 185 horses.
I rewired hi-fi unit a dozen times over in 12 months period trying to rid the system w/ the whine. Eventually, one of the installers I was talking to suggested running a capacitor. This solved my issue.
I ran into a same problem w/ my 94 Z. All I know is it worked. $5 and 10 minutes is worth a try.
Ground loop isolators solved my popping issue as well.

[secondchance]

As for "ground loop isolators" otherwise known as signal transformers this may help but .... I'd be pissed at the harness manufacturer if this is so since they claim to be compatible with Bose. I do think this is the case here and is why I asked for a wiring diagram from the vendor to be posted. Generally I think this is a fly-by-night vendor just scooping up $ for a piece of crap. I'm waiting the hear what a new head unit and harness does. (as was posted)

My understanding of why the pop occurs at turn on or turn off is due to the amp reading voltage dirrence at ground point as various electrical equipment shuts off and confusing this with audio signal (I am no expert but this is my understanding from reading internet postings). Solution would be to shut off the amp before the head unit but w/ radio/amp being connectedour "courtesy" circuit made this solution tough. Again, GLI solved this annoying problem.

[aod]

Update: It needed ground loop isolators. Once those were placed inline, it took care of all the popping issues as well as alternator whine. It seems like a kludge to me, but the system sounds good now. Thanks for all the ideas and help!

[secondchance]

Update: It needed ground loop isolators. Once those were placed inline, it took care of all the popping issues as well as alternator whine. It seems like a kludge to me, but the system sounds good now. Thanks for all the ideas and help!

Glad it all worked out.:cheers:

[scottfab]

Update: It needed ground loop isolators. Once those were placed inline, it took care of all the popping issues as well as alternator whine. It seems like a kludge to me, but the system sounds good now. Thanks for all the ideas and help!

Well that pretty much proves the harness you bought is a poor design and that the claim about comparability is false. A well designed adapter would have included isolation (either optical or transformer)
AND they would have actually plugged it into a Bose system and found the noise issues.
It comes as no surprise to me that just running a single ended source into a differential amp input would have issues. Apparently this is what the harness tries to do. Pretty fly-by-night if you ask me.

[aod]

And alternator whine is back. It came back last night while just driving around. It doesn't pop when turning on or off though. Can these ground loop isolators go bad? I'm worried the alternator is on its way out but hoping for just needing to replace those isolators.

[secondchance]

And alternator whine is back. It came back last night while just driving around. It doesn't pop when turning on or off though. Can these ground loop isolators go bad? I'm worried the alternator is on its way out but hoping for just needing to replace those isolators.

First, turn the volume down to zero. Do you still hear the whine with engine idling? If yes, get close to all 4 speakers and see if you hear the whine on all four or one or two speakers. If you hear the whine on one speaker, disassemble and scrape 6 pins on the amp where the harness plugs in. You might have poor connection.

Good luck!