Hello,

I connect +/- signal from my head unit to the amp's high input wires L/R +/-
but the sound quality is not acceptable (as well as when I set the balance
to left/right BOTH of the speakers connected to the amp are still playing).
There is another, fifth wire in the high input section labeled as "signal
grnd". When I connect it to the chassis ground the sound is good but: 1) I
do not know WHY it helps 2) Naturally I get the alternator whine noise (I
understand that "signal grnd" doesn't mean "ground" ). Anyone can help?

thanks in advance,
Luk