engine sounds through speakers

[nosaj26]

i have just wired up my lovely new 600 wat 4 chanel amp, its currently only powering my rear parcel shelf speakers, and it sounds great, however - as soon as i start the engine you get a high pitched sound through the rear speakers and as you drive down the road it plays back my acceleration and engine sounds through the speakers!!!! it sounds like a high pitched distortion and its driving me mad! any advice on how to cure this or what i have done wrong?. ps the speakers on the back parcel desk are 6 x 9 3 ways if this makes any difference, please help

[Dizzie]

it's down to a poor earth somewhere. the signal tries to 'go home' using another path if the earth isn't good enough. usually down the RCA cables burning out the earth track on them.

what make is the amp?

[nosaj26]

some german make off ebay, i know that sounds dodge but it really did sound the nuts till i started the engine!!!! il check the earthing, many thanx

[rwalker]

Things to try: Shorten earth cable.  Bare metal contact for the earth.
That should work, if not there are other things you can do... I just cant remember off the top of my head 

- Ross

[Dizzie]

could be down to cheap components...

mine did it to a £800 kenwood headunit 

[nosaj26]

did what to it dizzie?

[GazB]

Or it could be the rca cables running too close to the power lead

[nosaj26]

cars in garage at mo, il have a go tommorrow see what happens, cheers people

[nosaj26]

still no success!!! anybody recomend a good point to earth the amp to, its currently connected under the rear seat, any advice will be good

[HARDCOR3]

buy a surpressor from motor spares, stick it in the live, job done......