Dumb A s s Question

[Len]

I should know this but here goes :-

Have a 4 channel amp driving a sub and 6x9's in the back and am getting a high pitched whine which varies with the revs.
I think this is the earth problem but is it likely to be the earth wire from the amp in the boot or on the headunit??

[tobz.]

Most likely to be the amp dumb a s s
Do you have some front speakers running straight off the headunit Len???
If so is the whining present on those if you put the fader right into the front???
By trying that out you can isolate the problem to either headunit or amp.

[Len]

Yea thanks tobz, hadnt thought of that! Yea all four door speakers are off the headunit, so I could try that and either turn the amp right down or disconnect it.

[tobz.]

Here's the link to a handy document I found a few years ago when I was struggling with my system:

https://resources.myeporia.com/company_38/techpaper103.pdf

Makes interesting reading if only to understand the principles behind why things end up making horrible noises.

[Len]

Wow! That is a good one!

Will have to sit down and really read that! and digest.
Cheers tobz

[tommk3cab]

yeah it will be your earth to the stereo although if you havnt messed with it and it just started by itself it shouldnt be, it could be the whatchamacallit has gone on the alternator, in which case it will be that, i think its just called an rf surpressor but not too sure.

that is if its with your standard speakers too, if its just the amp it would be an internal amp fault i would say. can you hear CD's spin up aswell?

[Heyho]

First thing to do is replace your headunit earth with a nice thick piece of wire, and go directly to the chassis.

Also re-earth your amp - remove/check/clean connections.  Do this with the power supply also.

If this fails, you could try earthing the RCA shield/earth to the chassis/case of the headunit.  If you're still having trouble, try to blag another amp to try, just in case it's gone tits up.

[Len]

Its all fairly new stuff, no standard speakers.

From reading what tobz posted it could be a ground loop as I'm using an existing earth point.

[giffy1988]

iv got this noise and i like it lol. its only present when the stereos on about level 1.does it cause any damage???

[Len]

Only to your ears! And enjoyment of the music!
But dont think it will actually harm anything.