Timeline for How to break this ground loop in my car?
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| Nov 14, 2018 at 4:20 | comment | added | user105652 | @darksky. Glad to see you making an effort to track down the noise. Car power amps are often tied with heavy gauge wire to the positive battery post, which is NOT quiet. Custom high-current inductors can be expensive, so 'rolling' your own could save you lots of money. Use a large toroid if possible. Only turns that go thru the center of the toroid count as a turn. | |
| Nov 14, 2018 at 3:53 | comment | added | darksky | @Taudris turned out the head unit was not the problem. In fact I removed all the RCA's and the amp alone connected to nothing else still had alternator noise. I may try to get a big ferrite core and coil the battery cable around it a couple of turns to attenuate high frequency in the power line that goes into the amp. | |
| Nov 4, 2018 at 14:40 | comment | added | Taudris | @darksky Have you solved this issue? What ended up being the fix? | |
| Oct 1, 2018 at 23:07 | vote | accept | darksky | ||
| Oct 1, 2018 at 21:15 | comment | added | user105652 | @analogsystemsrf. There are situations where stupendous amount of power are needed because there is 5,000 watts of power in the trunk. A battery spliter, extra large alternator/multiple alternators, deep cycle batteries and supercaps packed the trunk, which was usually an older car with giant trunks. The only place we could put a RFC filter was the head unit, which usually fixed any whine problem. | |
| Oct 1, 2018 at 5:22 | comment | added | user105652 | @analogsystemsrf. With all due respect most of the time an inductor in series with the head unit power got rid of the whine completely. Local Batteries and Supercaps were for systems with 1,000 watts of power-or more. To a certain point very heavy gauge wire was good enough. For the amps it was not so much about whine as it was power starvation from skinny power feeds. | |
| Oct 1, 2018 at 5:02 | comment | added | analogsystemsrf | You want to create LOCAL BATTERIES for the "whine frequencies". That means a 2-element Low Pass Filter. A series inductor and a shunt capacitor are the method. You may need to provide some dampening; A series value would be Sqrt(L / C). | |
| Sep 30, 2018 at 23:22 | comment | added | darksky | Thanks. I didn't think a series choke in the way of power to the head unit might solve the alternator noise. I'll try that sometime soon. | |
| Sep 30, 2018 at 23:01 | history | edited | user105652 | CC BY-SA 4.0 |
Added paragraph titles.
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| Sep 30, 2018 at 22:53 | history | answered | user105652 | CC BY-SA 4.0 |