I recently installed a Pioneer DEH-P7700MP receiver unit and an Infinity Basslink into my '93 Toyota Celica GT-S with the System 10 (a factory premium stereo system option which includes 10 speakers and an amp). I previously had an old Sony headunit for about 3-4 years, but which was not connected to the System 10 (unlike most cars, there are 3 connectors in my stereo system: 2 connectors are for your typical wiring harness, the last one is for the System 10). I purchased a separate wiring harness which connects the left over System 10 connector to the receiver's pre-outs. Ever since I installed the Pioneer unit, I've noticed that I've been getting strange background audio noise no matter what source the music comes from (radio, CD, and auxiliary). There seems to be 2 different background noises. The first is a constant volume, constant pitch noise that sounds like radio static. The other is a high-pitched "whining" noise that usually increases in pitch as the rpms increase. So far, I've been drowning out the noises by playing my music louder, but when I want to lower the volume, it becomes rather annoying. If it helps, here's a timeline of my audio system: 1) Stock System 10 - no whining noise 2) Sony head unit without System 10 connected - no whining noise 3) Pioneer head unit and Basslink without System 10 connected - no whining noise 4) Pioneer head unit and Basslink with System 10 connected - whining noise present Is this occuring because my factory amp and the speakers it drives can't handle the higher voltages from the pre-outs (that is, it can't handle the cleaner signal)? Or perhaps, it's because they've been lying dormant for such a long period of time? Any help would be greatly appreciated. Thanks in advance.