I recently installed an AutoSound stereo radio and have static noise that I can not eliminate. The noise is engine related, ignition induced I think, as it increases and decreases with engine speed. The original shields have been removed and a MSD distributor with 6A capacitive discharge multiple spark control box installed. Spark plug wires are Taylor spiral core noise supression type. What I've done so far is: installed a grounded filter on the alternator out put, installed a capacitor from the coil + terminal to ground, installed a MSD noise filter into the control box power lines, installed a filter in the radio power lines, added an extra ground to the antenna housing in the trunk, and installed a antenna noise filter between the antenna cable and radio. The only thing that made a significant difference was the radio power line filter. Any ideas?
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Dave, I think you're shopping in the wrong...
...department store. Most of us dummies don't fiddle with the type of modifications you've made to your car. Not that there is anything wrong with that - we just have very limited info about that type of stuff. I'm sure there are some chat boards that can assist you. Good luck - have fun with your car. And, of course, you've chosen a good year Corvette to fool with. Best, Dennis -
Re: C1 1962 radio noise
The Corvette Gods are getting revengeBobComment
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Re: C1 1962 radio noise
Dave,
The main source of the problem could well be the Custom Autosounds radio.
I put one of these pieces of crap in a driver car of mine a couple of years ago, and it failed after less then 3 hours of operating time, and even when it was working, it sounded like hell! I have never heard ANYBODY have anything good to say about one of their radios, after owning one. I know that I will never give them another dime of my money. I would use the unit I have as a door stop, but it is not even substantial enough to serve that purpose. After opening it up and looking at what was inside the case, and how it was built, it was no wonder it sounded so bad. It just goes to show you that you can sell almost anything if you get it on a couple of car shows on TV.
Regards, John McGrawComment
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Re: C1 1962 radio noise
Interference noise can be radiated and/or conducted. Conducted noise (traveling along the car's electrical system) is usually 'hushed up' at the source using a strategically placed capacitor to 'gate' high frequency components to ground. Radiated noise can only be addressed with shielding (both around the source of the noise and/or around the radio receiver).
You've identified the noise varies with engine RPM and that's a start! Typically, a 'whinning' noise that varies with RPM comes from the alternator/generator which is why alternators have a built-in smoothing capacacitor to 'shape' the structure of their output current and voltage regulators have an external capacitor on them.
RPM varying noise that sounds like 'hash' is typically air borne radiated from the the distributor and plug wires. That's why ignition shields were installed over the distributor and around the plug wires with Corvettes ALWAYS having their radio antennas position away from the engine compartment (at the rear of the car).
Sounds like you've done as much due diligence as you can, with one exception... Check out the integrity of the antenna lead-in cable. The antenna cable terminates with a bananna plug that inserts directly into the back of the radio chassis (could insert into an in-line bananna receptical with a short run of cable to the chassis on aftermarket radios). The lead-in wire is shielded (braid surrounding the center conductor) and if there's a fault in the shielding, the back of the radio installed in the dash is pretty darn close to the firewall and the engine's rear spark plug banks.
Try disconnecting the radio from the existing antenna and connecting a 'test' antenna (antenna with captive lead-in wire can be purchased at WalMart for less that $10) and have a helper walk the second antenna outside toward the rear of the car. If your interference drops dramatically, you're probably fighting a defective antenna lead-in cable...Comment
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