Any body have some good advice to eliminate the rpm whinning noise from my 70 aftermarket stereo /cass.Its a custom autosound head unit with a 500 watt amp and 4 speakers.I get the engine whine all the time.Any body have any surefire solutions what to add to system to eliminate this damn headache.Thanks.

 

I think plug wires can cuase this but im not sure.

 

Ignition noise would make a clicking sound at idle and change to a whine as rpms increase. Alternator whine will sound like a whine all of the time but no clicking sound. Alternator whine could be caused by a bad ground on the stereo and/or amp. Or, other stereo wiring. Try the radio with the amp bypassed to eliminate the amp as a cause. Ignition noise might be cured by using different plug wires or reinstalling the ignition shielding if it's been removed. You can also buy filters that go in the positive side of the wiring to radio.

 

Or, it could be you are listening to Rush Limbaugh....

 

A whine would lead me to the alternator. Radio Shack used to sell a filter that hooks onto the Alt output. I'd guess that any good car stereo installer will have a variety of medicine to fix you up.

 

I agree with ahoover. A constant whine (other than Rush ) is a ground issue and that is almost always the prob. Filters are my 2nd choice.

 

Another possibility is the audio cables are running parallel with a power wire, they need to be kept seperated.

 

here is more then likely what you need... Check with radio shack or auto sound dealer first before paying this price with shipping.

http://www.ecklers.com/product.asp?p...dept%5Fid=1013

 

Hrm... I hear buzzing in my speakers when my RPMs are like 1200 - 1500. Otherwise it's not there.

 

Any auto shop should be able to sell you a suppressor alot cheaper.

 

First, let me qualify myself...sometime we can be misguided on these issues. I'm currently an electrical engineer...I design government receivers/transmitters/antennas. I've installed many car stereos in my younger days (used to work at a high-brow audio outfit in Nashville Tenn (Nicholson's Stereo (sp?)).

Where the noise is coming from is pretty much a who-cares thing. We know where it’s coming from…the engine!

The first and easiest solution that should be attempted is, as stated above, install a three wire “noise suppression” filter in line with the power to the offending unit(s). If you have multiple units such as external amplifiers, equalizers, head unit, etc., then you may have to install a filter on every unit. Note that the head unit will have two power leads (RED and Yellow) both of which may need filtering. Make sure you add the filter between the fuse and audio unit.

If that doesn’t work…The next easiest solution is replacing the low level audio cables that run from the head unit to an external audio unit (if applicable, If not, move to the next step). This is rarely the cause of a noise problems, but it is possible if the ground internal to the cable is broken…and it’s relatively easier to do than the following last-resort procedure as stated below.

If this doesn’t fix the problem, or does not reduce the noise level enough, then you have a lot more work involved. The key to removing “engine noise” is proper wiring, especially, but not limited to the power lines. The power lines are usually the vehicle for transmitting noise to the audio system…as stated above, sometimes it can be a defective low-level audio patch cord (the RCA cables running from the head unit to the amplifier or other accessory unit).

The best way to wire car audio power lines is:
1) Remove all previously installed noise suppressing filters.
2) Install one very large (alt least 10awg) multi-strand ground wire directly from the battery to each audio unit. If you have one amplifier and one head unit, then you need two ground wires, one to each unit. Do not daisy-chain ground wires. Try to route the wires away from other wires. Note that with the way I’m detailing this procedure, experience tells me that wire routing is not the primary cause for engine noise. Sometimes keeping the wires away from others isn’t possible, but we have to make an effort. If at the end of this procedure, you still experience a small amount of engine noise, then properly installed noise-suppressing filters (as described above) will absolutely eliminate the problem.
3) Make every attempt to isolate external amplifiers or other accessory units from any ground connection other than the main ground wire (Don’t mount them directly to the frame).
4) Install one power lead directly from the battery to each audio unit (through fuses of course). Note that external amplifiers require larger wire due to larger current draw…consult the audio unit manual for proper wire size. If you’re not sure…make it big.
5) Did I mention one very large ground wire directly from the battery to each audio unit?
6) Make sure all connections are tight and the battery terminals are clean!
7) If the noise is still present at this point, install a noise filter on the RED power line of the head unit. If everything was done correctly, there should be no noise. If there’s still noise (this is a very rare case) it should be significantly reduced. Finish filtering the rest of the power lines with filters one at a time making sure the ground lead of all the filters is connected only to the main ground lead for the particular audio unit being filtered.
8) Did I mention one very large ground wire directly from the battery to each audio unit?


Good luck

 

At least you have a radio to listen too. I would love to have that option and take the whining sounds. Try replacing the positive from another location to the radio. I used to do this by tapping into the fuses box with the wire from the radio. Also check the ground wire.

 

Very good advice and I'd like to add that a 500 watt amp will draw close to 50 amps on peaks. There are no internal dash points that will handle that kind of current. So the heavy cables should be used to the battery reguardless of the noise.

 

I took the amp out of the loop and now have no noise, I think my issue was the speaker wires were right next to the amp.

 

The original AM/FM stereo Delco radio made the whine just as the replacement AM/FM/cassette - separate CD player unit I have installed now does when the radio is on. The CD player which goes through a FM modulator to the radio and the cassette player have no whine.
I have heard about a bad antenna ground.
Any thoughts on my situation?
Roger

 

mine does the same thing when the cassette deck is on not the radio thou????????????????????

 

I have a custom auto sound, or whatever it is, replacement and also suffer from the whine. I had put a filter on the main power from the fuse box and never managed to eliminate the whine. However, it occured to me that there is a second power line which keeps both the clock and radio stations set up. I did not put a filter on that line. It would seem as though the second power line is another source of the whine.

Mark

 

From experience, the speaker wires are not very susceptible to introducing noise…there isn’t any more amplification at the speaker output. However, all audio units are not created equal. There are inexpensive brands that incorporate a technique where the ‘Neg’ wire for speaker connections are internally connected to chassis ground. This design practice can lead to engine noise being introduce if the speaker is also grounded…in effect creating a ground loop, the very thing we want to avoid. There is also the possibility that one or more of the audio components are defective (poor internal ground connections) causing the engine noise. I developed an intermittent engine noise problem in the Vette last year. Turned out to be a broken ground connection internal to the sub woofer amp.

 

Yes, both power leads may need to be filtered. Make sure the filter ground is connected to the audio unit ground...hopefully, there is only one. If you ground it to a different point, like the vehicle frame, you may not be getting the full filter benefit.

 

CS2 is correct in everything he said to do..but he should have mentioned one final thing....

MOST power amps today, and most ALL head units are designed for price point....CHEAP, and as such have inadequate internal designs/construction techniques.....

Amps guilty of this do not have their own power supplies, known as chopper or oscillator type supplies going into a typical torroid transformer, THEN to power the main amp....without that additional step, the amps willl be guilty of alternator whine....some worse than others of course, but all guilty....

head ends don't bother with chopper supplies, they don't need it for their operation, but I believe it's the only way to allow total isolation form that 12 volt line, all the chokes and caps in the power circuits HELP, but do not totally eliminate the problems....

Years ago, I had a Sony portable CD player, which needed a 12 volt source, with choke and so forth it would still whine through the stock system....

it's replacement needed a bi polar supply, so I built a chopper/torroid little kluge to run it and of course it worked like a charm, not ONE ounce of alt whine....

GENE