Review on Enhanced Noise Filter B25N: BOSS Audio Systems Ground Loop Isolator for Optimal Car Audio Performance by Jay Williams

I bought this to eliminate the hum from an amplifier and subwoofer I had installed in the trunk of my car. Worked great and completely solved the problem. Unable to find any parametric output, I dusted off my old signal generator and true RMS voltmeter and ran some simple tests. As far as I can tell the frequency response from -3dB on the unloaded output is <5Hz to >20kHz. The gain is approximately unity and is fully symmetrical, meaning the input and output connections can be swapped with no difference in performance. The only small problem was that the channels were crossed, so the white input was connected to the red output and vice versa. Also, I am very impressed with such a cheap device!