[frazierfrazier]

I've always had my stock Becker radio in the car. I used a cassette adapter to listen to the ipod, but I always got a horrible alternator whine/buzz in the speakers when I used it. I just assumed it had something to do with the radio being old, or a bad ground or something.

I recently upgraded to a Kenwood KMM BT318u. Weak output, comparable to the becker, but lots of features I wanted (including the omission of a CD player), and RCA outputs for sub, front and rear, because the next step was to buy a nice 4 channel amp to power the rest of the system I've been planning.

Until this... I have the amp I plan to use for the sub already installed in the car. I'm noticing the SAME alternator hum/noise that the becker was producing, coming from the sub amp (but NOT from the speaker outs direct from the receiver) It's not terribly noticeable, but I expect I'm going to have the same issue with the 4 channel amp, which will make the sound EXTREMELY apparent.

All of my grounds are good. The level of the noise does not attenuate when components/wires are moved around. I'm very close to getting a new alternator to see if this will solve the problem, but I'd obviously rather not if there is a solution I'm overlooking..

Also, I'm sure this goes without saying, but the noise is only present when the engine is running.

 

[304065]

I've always had my stock Becker radio in the car. I used a cassette adapter to listen to the ipod, but I always got a horrible alternator whine/buzz in the speakers when I used it. I just assumed it had something to do with the radio being old, or a bad ground or something.

I recently upgraded to a Kenwood KMM BT318u. Weak output, comparable to the becker, but lots of features I wanted (including the omission of a CD player), and RCA outputs for sub, front and rear, because the next step was to buy a nice 4 channel amp to power the rest of the system I've been planning.

Until this... I have the amp I plan to use for the sub already installed in the car. I'm noticing the SAME alternator hum/noise that the becker was producing, coming from the sub amp (but NOT from the speaker outs direct from the receiver) It's not terribly noticeable, but I expect I'm going to have the same issue with the 4 channel amp, which will make the sound EXTREMELY apparent.

All of my grounds are good. The level of the noise does not attenuate when components/wires are moved around. I'm very close to getting a new alternator to see if this will solve the problem, but I'd obviously rather not if there is a solution I'm overlooking..

Also, I'm sure this goes without saying, but the noise is only present when the engine is running.

Its alternator whine. Get one of the spectrum analyzer apps for your phone, listen to the noise it will show you the waveform, and of course it varies with engine RPM.

I get the same garbage running an unshielded iPhone charger with my Becker Mexico that has been converted to AUX input (from iPhone). It hums like crazy when the phone is charging, and is pure when it's not.

These kinds of radio noise suppression issues have been around since the 1950s and they are simply a question of 1) proper grounding 2) ignition resistance (to avoid high-frequency transients) and 3) capacitors on the alternator output to "smooth" the fluctuations caused by three phase AC being rectified into "rippled" DC.

Do you have a scope? I guess if you did you wouldn't be asking, but for now, disconnect everything until the noise stops, then filter the power on what's left.

Good luck!

 

[okyoureabeast]

Another suggestion, which isn't as good as the others here, would be to "EQ" the noise out.

Open up your equalization panel or on your becker, press the bass or modify the EQ settings until the sound disappears. You may flatten the range somewhat, but it's a cheap easy fix for something that stays around.

 

[frazierfrazier]

Another suggestion, which isn't as good as the others here, would be to "EQ" the noise out.

Open up your equalization panel or on your becker, press the bass or modify the EQ settings until the sound disappears. You may flatten the range somewhat, but it's a cheap easy fix for something that stays around.

I do studio recording/live sound for a living and that option.. well, it's just not an option for me. Getting decent sound in this vehicle on a limited budget is pretty darn difficult.

I spent awhile reading the 107 audio thread and got a few more ideas. I'm going to run wire directly from the pos battery terminal for all of the amps and see if that eliminates the noise, then do even more research. I think a noise filter would be a last resort.

 

[Taurine]

These troubleshooting guides might help:
https://www.crutchfield.com/S-Pstyg...car/noise_suppressors_installation_guide.html
Curing Radio Noise

 

[Walt Williams]

With my 54 Chevrolets they used to use a ignition condenser as a decoupling capacitor on the generators to reduce noise.

 

[masand68]

Your rca cables between the head and the amp are shielded, which should block the noise. If worn, you might try replacing the cable. Also, if you are able, it might help to route them with physical separation from any power wires.


Sent from my iPhone using Tapatalk