Hi, i had to change head unit as multichanger had unrepairable fault. Connects to i-pod and all is well however, when volume is low there is a faint "whine" coming from all speakers. Also if you listen very carefully whilst indicator is flashing there is a very quiet clicking as the indicator flashes. This never happened with original head unit. I took it back to installer who told me problem was due to having amplified speakers. However when i got home i noticed that fault(s) don't occur when engine is switched off. It sounds petty i know but, when driving with passenger it can sometimes be very irrititating (the noise not passenger generally!!). Should i go back to installer??? Thanks in advance for any help.