most likely coz by amp or wiring. Maybe you need to get to the accessories shop and get the wiring check to ensure no leaking or touching other parts of the car. Normally for the main power cable wiring from battery to amp, the installer should wrap them with a protector stripes, check if this is done.

If you cannot trust your current installer, I advice you to bring to KK Lau for checking where he has good workmanship.

check out KK Lau website at www.kklau.com.my. His shop is around at Ara Damansara. There is a contact number on the website. You can call. Maybe u better bring to the pro to check it out.

If your Nakamichi player got problem, just got it fixed better than buy the RM1k+ Pioneer player unless u wanna change to other more "oomph" player like Clarion HX-D2, Alpine or Pioneer P99RS.

Sad for him if need to chuck the nice Nakamichi player away ....