Which signal converter? I need a new one.

RonRizz

Two things.... first, are you sure you have your gains set properly on both converter and amplifier? second, that unit also has a signal ground that you may have to connect. check your literature and connect as advised. it may or may not help.
Ok, Three things.... you cannot simply connect your ipod/phone/ect to the rca cables running to the amp to help rule out noise sources because they are not grounded to the chassis of the vehicle, as are all the other integral components of your system. you need to stay in the realm of your current problem (although you have given it more thought than most would have, and should be commended for doing so).
Finding the source of the dreaded alternator whine can be a very simple task, or a long and tedious one. I've spent more than my share of time re-routing wires, checking solder joints, ect... I feel your pain, and wish you well.
At your wits end, consider the Audio Control LC2i.

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