I've been having a trouble with high pitched engine whine in the speakers of my 77 and the noise increases when the engine is reved. I have been looking thought the forum and other websites to troubleshoot and I've had minimal success. I've tried several things and I'll outline below, but frankly I'm at a loss and hope you guys can be some help.

I've done a frame off restoration, and the alternator is new, the ignition shielding is back on, the capacitor by the distributor (which helped when I put that back on) is on. I have a new retrosound model 1 stereo that runs two rca lines to a rockford fosgate punch 4 channel amp that is in the left storage compartment. There are speakers in the dash and component speakers in the lids of the storage compartments with tweeters up by the seat belt bolts. The RCA lines are ran through the console on the right side (away from the rest of the wiring). The amp is wired pos/neg to the battery. I have a dedicated lines on the left side of the console to the battery for the memory line and the ground to the radio. I've wrapped the radio with double sided aluminum insulation (extra that came with the insulation kit for the body).

When I unplug the RCA lines from the amp, and plug in an mp3 player/discman to the amp inputs, i get no noise through the speakers. When I plug the RCA lines back into the amp and unplug them from the radio, I get the whine. I had an RCA noise suppressor that I tried on one of the lines (removed the other) and it did not help at all. Of course when i plug the RCA's back into the radio the whine is there. Since the RCAs plugged into the amp and not the radio made the whine, I tried wrapping a copper line around the jacks at the radio and grounded them and it made the problem worse.

I'm trying to avoid buying noise suppressors for either the RCA lines or the power lines since they mask the problem and not eliminate it. Any suggestions? I'm been at this for awhile and am really struggling here. I know a common problem is check the grounds, but the radio and amp are direct wired to the battery (power and ground), and I even wired the ignition line to the battery from the radio as a test and that didn't help either, the whine was still there.

I've seen some comments about a better ground at the alternator? i haven't tried this yet. Thanks!

 

Have you got the distributor shield on? Thats what its for.
I've taken mine off because I'm using an MSD so I use a noise suppressor. Works for me. If it didn't though , I'd rig up the distributor shield.

 

try and use the same power supply and ground as the radio

 

Yes, the ignition shielding is on and yes the radio and amp are both direct wired to the battery.

 

The whine is coming from the alternator-

Could be a couple of things-

If the alternator is good- and you said it was new...

It's not the amp or speaker since you are not getting any noise w/ RCA's unplugged at amp.

Unplug the antenna...see if this stops it- means bad ground at the radio or you can use antenna isolator at the back of the radio- very common in Vette's because fiberglass does not shield...

If still present- get another set of RCA's and run away from the console- to the amp...I'm guessing it could be from your main power wire (battery to starter) that runs right UNDERNEATH the console on the RIGHT side....

Let us know how it turns out-

Richard

 

Good thoughts Richard! I forgot to add a couple details that I tried.

i have a hidden antenna that is adhered to the top of the windshield. It has the antenna jack and a seperate line for the power lead to the radio. I unplugged the antenna jack and the noise was still there.

I totally did not think about the main cable in the trans tunnel! I actually tried a seperate set of RCA cables draped over the pass seat to see if it was the RCA cable since i got the noise with the cables plugged into the amp and nothing at the other end. When I did I got the same noise. I do have the double foil insulation on the inside of the car over the tunnel. I don't know if that would negate the interference of the main battery cable going to the starter.

 

I spent the winter of 2011-12 working the bugs out of the stereo install in my '79. Without trying to analyze what you have done, here is what worked for me. I had a static discharge that would not go away until I replaced the Pioneer head unit with one from Sony. I also had the whine much like you are describing. I traced it to the proximity of the amplifier to the battery in the compartment behind the seat. I found that when I moved the amp away from the battery, the noise went away. I finally relocated the amp to the space under the right side compartment and relocated the jack to the spare tire tub in the back. I bet I have a hundred hours in the install. Really!

 

i got rid of my whine,when i put a battery cable from the back of the alternator to the frame.

 

OK...sounds like it a ground loop in the RCA's I don't know what kind of HU you have...wrapping foil is is not really gonna help- unless the shielding is grounded...

Pull the radio out of the dash so it's not touching any metal-disconnect antenna- run the ground wire (will have to lengthen it) to the same location you have the amp grounded.

This should stop it...if not -is the HU a Pioneer?

Richard

PS- Guys it's NOT his amp or speakers- as he had no noise w/ RCA disconnected at amp...

 

Had similar issues with alt whine.Tried all the usual remedies none worked.Finally tried using line output converters and the whine is gone! Cost was the converters about 20 bucks and some speaker wires.Used these units:
Good Luck!

 

drwet: Thanks for the input. I actually have a removable shelf that the amp is bolted to that sits above the jack in the right storage compartment. Hopefully that is a good location for the amp from an interference standpoint. I hope I solve it before I get that many hours in!

Terry: What do you mean by the back of the alternator? There is a ground post where the engine harness has a ground line going to the alternator. Did you go from that post on the alternator to the frame?

Richard: It is a retrosound model 1 HU. I do have the wrap grounded to the dash harness. The amp and the radio are both grounded to the battery. The radio has a direct line to the battery, just like the amp.

iokepakai: I'll check out the converters! Thanks for the tip.

 

Let me know what you do to solve this one. Pretty amazing that I have done everything you have with the same equipment....and the same buzz. Rockford Fosgate speakers, Sound Ordnance amp and Retrosound head unit. All ground and power wires go back to the battery and the amp is behind the rear seat.

I did notice that as you move the RCA's around under the dash... the intensity of the buzz changes.

I did buy a GLI and that helps somewhat but really reduces the sound level. I've done a lot and haven't fixed it yet. If I figure it out...I'll let you know.

 

Stick with this topic 'til it's fixed and let us know how you did it. I'm suffering with the same problem and kind of gave up. Went to many stereo stores asking what to try after trying everything the guys here suggested. Radio installers said to start trying different head units. One of them offered me a different h/u on loan to help troubleshoot. Unfortunately I was in a different town at the time. I have an alpine and he suggested a kenwood which I had previously and had no problems. Keep us posted.

 

yes

 

OK- sounds as though you have narrowed it down to the HU- use another power source connected to the radio- a second car battery would work great- and then start up the car. If it's not there then you have a few options...


As far a switching HU- yes that will work- because some manufactures do the pre amp outs a little different- I worked for Kenwood in the eighties and early nineties- and they had a built in isolator and even had balanced line outputs on the more expensive models. Never had the dreaded alternator whine in any of my show cars...


Taking the speaker level and converting it to "low" level preamp in will work- It's just not the best way to do it as far as sound quality...but noise is not quality anyway...

You can take a wire - touch the RCA ground and touch it to the HU chassis- this might work as well.

Good luck

And guys- every system noise problem is DIFFERENT...there is no ONE thing that will fix it all- Juskie has done a great job in steps to narrowing down the problem...

Richard

 

Find a blank channel, crank it up, and everyone will think you have a gear drive...........................

 

This was a real common problem with high end Sterio Systems of the 1980's. They used more componets than systems of today and there for had more ways of getting noise. It kinda sounds like You have your grounds in order, just make sure every componet is grounded to the same place, I used the Frame Ground below the Battery. I'd bet if You removed the Belt off the Alternator that Noise would go away. A Sterio shop installed a capacitor on the Alternator back in the 80's and its been there ever since. If You were to have non resitor spark plugs wich are very un common today that could help. I'm sure You have good spark plug wires as well.

 

Well, I've tried the following things in the past couple days:
1) played with ground on aluminum shield around radio
2) unplugged antenna and antenna power lead
3) plugged another rca cable and ran it away from the console.

None of these things made a difference.

I then ran a ground from the alternator directly to the frame and disconnected the ground from the harness that was on the alternator. I thought this did it. The first time I started the car, i swore I heard no noise, but the next time I started it the noise was back.

I also ruined one of my Rca cables when I wrapped the exterior shield with a copper line and grounded it...so i replaced that line. I still have the noise. I guess at this point, I've tried about everything and am going to order the alternator capacitor and try that. It will be a few days before I get it in to try it.

 

When I was chasing my stereo noises, one of the things I did was to wire the entire stereo to a separate battery completely removed from the vehicle. This meant there was no chance that the noise was beinng transmitted through the power and ground to the stereo. The noise was still there. That told me the noise was RF and I could stop trying to filter the alternator. Once I figured that out, I started moving the components around and that's when I figured out that the problem was the proximity of the amp to the battery. Hope my experience is useful to you.