So, I have this Tang Band 6x9 subwoofer I bought from parts-express.com and it's 90W rms @ 6.5ohm. I have this rca amplifier that's 2 channgels at 75W RMS per channel. So i bridged it from right channel positive to left channel negative. Supposedly that's the correct way to wire it up. However I have buzzing from the sub when the car is running and it goes away when i unplug the RCA's from the amp. So I bought a ground loop isolator and it doesn't work. So the tech said I need to bridge right channel negative to left channel positive with a small wire to get the full power from the amp. Anyone ever heard of that? He also suspected that once I do that, the ground loop isolator will work. The loop isolator works on the IP-BUS to rca's aux output that I have converted to 3.5mm stereo. However since the sub is in bridge mode and not sitting on channel 1 left right positive negative, it doesn't make any sound with the isolator. I don't get that? Any audio electrical guru's out there. I'm all yours brotha!