1st Source Torroid Choke Noise Filter

This is a bare-bones, 300 microhenry inductor that is placed in series with the +12-volt line to an automotive electronic item to eliminate alternator "whine" in the audio circuits output. In my case, it removed the clearly audible alternator noise on the transmitted signal from an Icom IC-2200H VHF-FM transceiver when that unit was set to its highest, 65-watt, output power and drawing 15 amps of current.This series inductor relies on the presence of a large filter capacitor across the +12-volt power line in the unit it is feeding. If that capacitor is missing, or degraded as is sometimes the case with older units, a shunt electrolytic capacitor of at least 4700 microfarads must be added between the +12-volt line and ground after this inductor. A better choice that covers such contingencies is the passive noise filter by DLC that contains this inductor and a capacitor in a plastic, tubular housing.ps: It's supposed to be "toroidal", not "Torroid"

it didn't work for my application. It made zero difference in the noise level. My noise comes from the electronic ignition module

Simple and worked to remove alt wine from my sound sys and amp. Should be put in insulated container but otherwise works well.

works great, got rid of speaker noise

We have a Motorola XTL 1550 radio that was put into a 2013 Chevrolet pickup. The radio was picking up a lot of alternator noise and transmitting it when keyed up. We installed this noise filter and it cleaned up the output transmission.