I bought a line amplifier for the front speakers to boost the amplifer output a bit. It goes in line on the RCA cables ahead of the amplifier to boost the signal to the amplifier.

Only thing is now I get a loud popping noise through the front speakers when ever I shut the car off or even when I activate/deactivate the solenoid on my Gear Vendors. It seems like voltage spikes are getting into the amplifier somehow.

Interestingly, I put a voltage suppression diode on the power line to the GV solenoid early on after installing the GV because occasionally the ECM would hiccup when activated it. The diode solved that problem.

Mind you, I have this setup filtered to the wazoo... power filters on the amplifier battery inputs, filter on the switched power, filter on the head unit, common ground point for everything near the ground on the battery. The line amp gets its power through the filtered power as well. I even tried a line filter on the RCA inputs before and after the line amp. But no change.

The popping sound doesn't get louder with increased volume out of the head unit. It also doesn't get louder or softer if I turn up/down the output on the line amp.

Any ideas on what's going on?

My next step is just to get an amplifier with higher power. This line amplifier seemed like an inexpensive option to boost the power (and it actually does a really good job at that). Just that this popping sound is very annoying.

 

no expert, but I like guessing games. How about a capacitor that is dis-charging and gets amplified by the in line amplifier. I don't like in-line amps, because they are likely to amplify any noise they get from a crappy amp behind them, well at least that is what happened in the late 70's