Review on 🔇 PAC SNI-1 Noise Isolator: The Perfect Solution for Noise Reduction – 1 Count by Brian Buck

I installed a new Kenwood head unit and 5 channel amp and the engine started to jitter. Making sure the ground was bolted to the bare metal of the body frame in the trunk, I ran a thick 10 gauge ground wire from the main unit to the same spot I had grounded the amp. I even grounded the radio case and the hum stayed. I routed the RCA cables on the opposite side of the car from the power cables to avoid possible interference. Using the Sonicelectronix troubleshooting guide I was able to narrow the problem down to a permanent ground loop issue. I've used two of these, one for the front and one for the rear, and the rumble is completely gone. The low-pass filter eliminates subwoofer hum. They were as easy to install as just plugging in and unplugging RCA cables. I didn't even have to run their ground leads to the main unit's chassis. I see no degradation in sound quality.