i dont know how much experience you have so i'll say a couple of bits from my experience that might help.

if you've amped the speakers, double check that the amp is off when the headunit has no power.

If not then you know your

"remote on" connection is keeping the amp powered which it shouldnt.

There could be a number of reasons for this, normaly a minor mix up on the wiring instalation but you'll probably find whats up quite quick if you run through where the wires go.

But remember as soon as you put the key in and turn it to ignition, some headunits send the

"on" signal to the amp and any interference being picked up will be amplified to the speakers, even without music playing.

The noise on through the speakers can sometimes be decieving, a guy i know sat me in his car and

"showed" me his hissing noise, both with the car only on ignition and again with the engine running.

turned out that the noise he could hear with the keys in but no engine running was his air blowers on low.

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.DUH! switch them off and it was crisp and clean, but he was suffering from whine when the engine was on.

we replaced the cheap non-shielded RCA's with shielded and made sure all earth points were clean and well secured.

This seemed to work fine for his issue, but as mentioned in most posts in these threads there can be many other reasons for whine.

in my mr2 i found that a bad earth on the head unit was the main cause of whine.

i replaced the existing toyota earth with a thicker guage mod.

I have left all the toyota harneses intact, but luckily my headunit uses a bullet connector to alow you to swap between a self made earth on a bullet or the ISO earth on a bullet so no cutting and bodging was required.

you can test to see where the whine comes from by eliminated sections of your sound system.

Starting at the head unit if your using RCA's unplug them from the back of the head unit

(with the ignition off and the keys out.

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.its not ideal to unplug them with the power on!).

With them unplugged turn the system on, if you have no whine then it is most likely to be something with the headunit, like the earth.

If its still there then the whine is being picked up or created further down the line so try the next bit

turn everything off again and unplug the RCA's from the amp, this will now eliminate the RCA's picking up interference.

Switch it all back on.

If you loose the whine now then its possible that the RCA's are acting like an arial and picking up interference, you will need to either re run them away from any electrical motors etc or earth them better

(the outer ring of an RCA is an earth, so can be grounded if required).

if you still have the whine then obviously its not the head unit or RCA's as they are no longer in the loop.

sometimes a faulty amp can be the cause or simply a bad earth on the amp.

double check all sockets and connections are both secure in the amp and all power lines are securely mounted at both ends.

i could keep going with suggestions but i feel like i might be starting to teach granny how to suck eggs.

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.where did that phrase come from anyway?

hope that helps a little