exactly , a transformer rectifier bridge is a silly little thing it causes problems in newer gas powered welders because they don't use generators anymore they use transformer rectifiers (alternators) magnetic flux lines off of wires ,grounds arc blow (in welding) etc , nothing to do with an engine all to do with electricity dc current to be more precise .how do you think an amp clamp works . anyway that sounds like an easy fix just grounding your rca's . good to know .