Amped speakers hum / whistle

Igloo

Igloo

Ex. Club Member
Hey guys,

I finished installing my new speakers on saturday.

Now, When the amp's on they buzz / hum like a badly tuned radio.

Also, When i accelerate, It produces a whistling noise, quite like that of a turbo / etc spinning up (which is cool, But not welcome :p ).

I'm just wondering, Is it the battery? Alternator?

In dire need of some assistance. :(
 
It's earthed to a bolt in the boot.

I'll try moving to a different place, brushing it down with a wirebrush.
 
also if you've got several earths for amps etc. try connect them up to the same place.
 
Had the same problem. Amp's under the passenger seat. and now earthed to the seat rail bolt. Hope thats any help.
 
One amp, Going to try different bolts :)

Tried different bolts.

Tried wiring direct to battery.

Now im stuck :(
 
igloo

if it,s changing note with engine speed, surely it,s interference? are you using non factory spark/plug leads?
 
Igloo, check your RCA leads. are they OFC or normal any cut and shuts. also try your amp and leads in another car just to pin point the cause.
 
I'll try my amp in another car... as soon as i can find someone with a car nearby :(

However, I am running stock leads, no cut and shut.

Would new leads work? new battery? alternator (though buzzes while car isn't running so can't be that).

Cheers o_O
 
Earth lead should be a maximum of a meter long, you are getting alternator whine, a common sign of a bad earth

Going straight to the battery will guarantee you noise, lol.
 
I've played with the gains, still get noise, the earth wire is short about 30-40cm?

I was just trying to work out what's going on :p
 
Check you have a sound surpressor on the alternator. Its a small metal thing about an inch long. They sometimes fall off and cause this problem

The other thing, make sure your amp power line is running down the opposite side of the car to the RCA leads.
 
RCA leads when unpluged, the whistling stops.

They were running along the side of the gearbox. I'll move them and see if that helps.

I'll check for that Arnold, Where about's is it?
 
Igloo said:
RCA leads when unpluged, the whistling stops.

They were running along the side of the gearbox. I'll move them and see if that helps.

I'll check for that Arnold, Where about's is it?
Click to expand...

The noise is therefore coming from your headunit, try giving your headunit a brand new and clean earthing point.
 
The whistling from accellerating stops.

Not the general static buzzz hiss noise.

Though that could also be todo with the ground on the HU, Will check it :)
 
It's not the RCA lead's, without them connected it still hisses.

It's not the HU earth, Tried multiple locations for that.

Is anyone near birmingham that can give me a hand? Or stratford upon avon? Or warwick? Or Redditch infact :p

Please, Need help :(
 
if its for 6x9's use a Ground loop isolator, if its for a sub, select "low pass filter" on your amplifier...

this should sort the buzzing noise out.
 
It's for coax in the doors......

and it's still doing the wining noise during acceleration, and i've moved where the rca's run :(

Where abouts is this sound suppressor on the alternator?
 
i'd get you a photo but i no longer have my car! its a small metal thing about an inch long, and should have a wire coming off it. Basically look at your alternator and see if anything remotly similar to the above is there. Get some photos of yours if your not sure and i'l tell you
 
I need to find someone else with an in car setup...

oooh, just thinking, would a battery charger work the same as a battery? (using trickle charge?)

Because this would be grounded to the house.... :)
 
My micra did the same when i fitted the amp. The RCA leads were picking up alternator whine. BTW is your HU fitted in the original nissan cage? because that should be earthed well. Also if its no inconvenience you can try those RCA's with a central ground wire.
 
Thats the one. Its worth a shot, "borrow" some and check em out. One side to the stereo chassis and the other to the amp chassis. dont tuck them away just in case you still have hiss!
 
I have a wire running down the side of the two RCA's, I'll try it.

I don't think the hissing is down to the RCA due to it hissing if NO RCA is plugged in.

Could it be because im using house speaker wire instead of car specific stuff? :(
 
Ok, Need to find someone local with an amp :(

The alternator whine is DEFINATELY from the RCA's though, as it doesn't do it if they are unplugged :s
 
Hey are you in birmingham? Im willing to have a look for free. send me a PM.
Ive got a spare amp for you to try.
 
Cheef said:
Hey are you in birmingham? Im willing to have a look for free. send me a PM.
Ive got a spare amp for you to try.
Click to expand...

You need to be an official member to receive PM's

and using standard house wire probably isn't all that well shielded from interference!
 
Im using speaker cable, From my install in the house. It should be shielded enough.

And Cheef email me igloo at multiplay.co.uk to arrange something :)

I'm going to get a pic of the alternator, and try and earth the RCA
 
RCA's don't need earthing directly. As above, it'l be the HU or Amp if it's not the alternator :)
 
I had double shielded RCA's running directly alongside my power and had no interference so it must be a problem with the amp.

When you move the gain controls do you get a grindy buzzy noise from the speakers?
 
I'd quite like to know what equipment / speakers and all that you are running too!
 
I have just moved the earth for everything, Including HU.

So it's not the earths.

I've just tried to earth the RCA's and it's not them, (though i need some higher quality ones as these are rubbish and i want matching pairs :) )

So, The only thing it could be is the amp :(

I need someone else's system to check it with though...

I'm running a JBL GTO 75.4 amp, with GTO 7507C components + tweeters, And a JBL GT4 12" sub. (not in use atm)
 
igloo

iv,e hot an amp you could try, but im,e the other side of brum (gt barr) and am not very clued up on ice !
 
hmmm i'll try cheef first :) I've tried everything else i can think of.

What setting should the voltmeter be on?
 
ollyc98 said:
No, it's definitely a noise picked up by your amp, try another amp on your current setup
Click to expand...

If the noise goes away when the headunit is disconnected from the amp, then the problem lies with the headunit.

I had double shielded RCA's running directly alongside my power and had no interference so it must be a problem with the amp.
Click to expand...

The power cable runs DC voltages, you shouldnt pickup any interference from that cable anyway so ignore that, its not the problem.

Igloo, do this if you can:

- Disconnect the RCA leads but have the amp wired up as normal, including the power/ground, REM cable, speaker cable, etc.

- Power on the headunit as usual, so that the amp turns on. Do you still get the noise and engine interference on acceleration?

Don't just assume its your new amp causing the problem.
 
Retepetsir said:
Igloo, do this if you can:

- Disconnect the RCA leads but have the amp wired up as normal, including the power/ground, REM cable, speaker cable, etc.

- Power on the headunit as usual, so that the amp turns on. Do you still get the noise and engine interference on acceleration?
Click to expand...

I already asked him to check that and although the alternator noise goes away he still gets white noise.
There are 2 problems here, alternator whine and static.

The alternator whine is probably down to a noise suppressor

The white noise is the amp.
 
Power readings:

(engine not running)

12.30v - Batt
12.28v - AMP

AMP / HU ON

12.23v - BATT
12.21v - AMP

It was steadily going down about .01v a second.

There are 2 problems, One being white noise, one being alternator whine as Olly said.

Alternator noise stops if the RCA are unplugged. White noise does not, Is there a way to turn the amp on without the HeadUnit being on?
 

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