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_1207018...r.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.crutchf.../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]

Originally Posted by 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.

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]

Originally Posted by aod

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

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...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!

[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]

Originally Posted by 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!

Glad it all worked out.

[scottfab]

Originally Posted by 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!

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.