07 tundra jbl common ground

OK, so this truck has had me crying like a little school girl for a few hours now.

So here is the deal... I'm installing a JL clean sweep in it and the outputs from the factory amp are not full range. So I need to take the line level inputs to the amp and feed those to cleansweep. But Upon testing and checking I've come to realise that the system is using a common ground for all four channels...like in older car radios which as we know can be damaging to a headunit, but is it the same for line level? Anyone with some input?

-------------

it would damage the OEM amp if you tried to common the output negatives.... but if you are grabbing signal at the input stage of the amp i dont see what the issue would be at all....most pre-amp outputs always use a common ground....

-------------
Kevin Gerry
Certified Electronics Technician
MECP First Class Installer

Owner/Installer
Classic Car Audio
since 1979

Yeah the deal was never to use a common ground on the outputs, I was trying to tag into the line level inputs of the amps, which I did, and it worked beautifully except for one fact...in this JBL system you can't have one without the other due to the data system, so when I removed the amp I also lost volume control and also tone, bal and fade so I had to go back to the drawing board and whipped out a JL CL-SSI to sum the outputs of the amp back to full range so I can feed the the actual JL Clean Sweep a full signal to do with it what it wants. I must say, I was impressed by the Cleansweep, is there any other products out there that are similar?