Grounding?

[04X3]

Alright, I installed the new one and the noise is considerably better. However, when the volume is full or when it is close to full, I can hear a quiet hiss from the unit (sometimes when I change songs I hear a tick as the unit is working). Is this normal? I can't really remember from before... I think my cable from the USAspec to the radio is fine, don't think I nicked that one while moving wires...but that's not even shielded is it?

However, I can only hear the hiss on very few songs and when in the middle of a song with a pause of silence while the volume is high. Am I good or am I getting excessive feedback from the unit?

All in all though, I'm satisfied.