Originally Posted by
EuroDude
Its the Stock head unit causing the noise. Mine has the same hiss. Reason being its a BTL audio system that uses a balanced (opposite) + and - to power the speakers, instead of + and 0volts like a normal sony/kenwood/etc.. head unit.
In a totally stock euro, you cannot hear the noise. Once you add an Amplifier, the noise is present. I tried many things including a noise filter, it helped but the sound quality suffered.
I believe you can get a BTL->unbalanced converter now, some TSX owners are using them.