Why does my music system keep humming.

[Colin]

Help. I have a Kenwood head unit running through a CD changer in the boot. All was well until I fitted an amp. The mains lead is straight to the battery. The earth is to the rear seatbelt bracket. The phono is one lead and splits from two plugs to four and plugs into the amp. The phono lead does not run next to the mains lead. When I switched it all on there is a distinct hum which increases with the engine revs. No hum when engine is off. I have fitted something, which I think was called an FM filter behind the head unit. The mains into the headunit is constant live. I cannot find a convenient live, which comes on with the ignition. Still it hums. Can anyone help?, as I am about to try a small explosive charge placed just under the fuel tank.

[12345kevin]

As it increases with engine revs, I would suggest probabably the coil, distributer etc. I've only just got back into working on older cars, but I do remember this used to be a common problem with radios. We used to fit "suppressors" to the coil & distributor. Might be worth running a temporary wire to earth direct to the battery, just to see if it improves.

Hope you sort it.

Kevin

[320Touring]

sounds like you have a dodgy earth there mate.

the earth lead from the amp must be grounded to bare metal on the car's bodywork.

if not, make it so

should resolve the issue for you

only other possibility is the amp has one or more dodgy channels

[amit325i]

As above, usually this is the problem, amps should not be mounted on to metal straight some mdf should be placed on metal first.

[Bayne]

Why does my music system keep humming.

Cuz it doesnt know the words.....





shit somone had to say it....

[johnono]

if uԚ´ve run the rca lead and the amp live next to each other , or if the earth is too long , or if the earth isnt a good earth, (there is an electrical current near by) then uԚ´ll get that funny wreeeeeeee that sounds like a toy turbo

[hammoj28]

My mate recently put 3 subs in the back of his focus with ams and stuff.Don't know the exact spec.Anyway he also gets this really loud humming that increases as he goes faster and slows down when he goes slower.Wierd!!