Aaaarrrrrrgggggghhhh

[Karma Supra]

Just finished installing a rather tastey Alpine headunit and/iPOD CD shanger setup into the MR2, it has the premium sound system with the active Speakers and subs and sounded awesome :D

I then got the other half out to show her the new stereo.. first thing she does is starts the car and gets the dreaded MR2 active whine :( (I had only tested it with the engine off. :(

I have done some searching and read up here and on Google.. and some people say an altenator supressor is needed (UK car) other say it is earthing issues... I have also heard Ground loop isolators mentioned...

Anyone fixed this easily? with a definative fix? What actually needs earthing, the head unit chassis? I'm ***** at sound systems!

Edit: it may be worth mentioning that I did NOT use the head units already amplified speaker out wire, The conversion cable I used took the feed from the Head units RCA connections

[T600]

I didn't even get that far.

When I tried a different head unit in mine I got a really loud pop from the subs when the unit was switched on so I reverted to the standard one. I think that was using pre-outs too and maybe the head unit was faulty as it came out of an old car and was mangled by the people who removed it.

I'm not sure if I even tried it with the engine on, but I would have said good earthing and suppressors would be the solution to that problem. I don't think either would be very expensive to try so that would perhaps be worth doing anyway. After that, you can consider a powercap or an entertainment Battery to isolate the head unit from the vehicle's power supply, though ideally you'd run the amps off the isolated supply too and I don't know how tricky that might be.

Is the noise the same whichever input you select, or is it worse when you select a particular channel e.g. the Radio?

I've resolved to have another go some time soon as I now have the Kenwood that we used to have in our old Rolla and I know that's a very high quality piece of kit. So I may run into the same problems if I get over the sub pop noise.

Good luck and let us know how you get on.

[Karma Supra]

Update:

I had a nother play this morning... put the factory head unit it, its perfect... put the Alpine one back in and I get the whine. I disconnected the RCAs and fired it up, the whine was still there so its coming from the amp, not the source.

I am about to get experimental with tin foil shielding and lots of earth straps....

[Karma Supra]

Solved.....

For the sake of the search engine:

Wiring diagram

I didn't think to check that the actual wiring harness converyer would be wrong... It was an earth.

The earth that is meant to run to pin 12 have been put on pin 10, that connects to nothing.

Job done!!