Ralphh85

im running M2 ATX/jetways F4/sony amp.

when i turn the pc on half way through the boot screen when it says windows is starting.... this slight humming can be herd, i think it coinsides with when windows starts its sound device.

how can i stop this?

i notice theres a 0.05v difference between negetive on both sides of the M2 ATX, so the mother board and the amp have slightly different megetives, could this be the prob?? would it fry anything if i grounded negetive out on the PSU and on the car?

cheers
Ralph

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RedGTiVR6

have you matched your gains on your amps?

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Ralphh85

erm, not sure what you mean, i turn the gain up so it sounds bout right, this hum is when it should be silent, so what the opc thinks is silent the amp thinks is a hum...

Ralph

cbevis

do you have any audio lines running in tandem with power lines? Power curent causes feedback...AC current usually causes a pulsing sound out of the speakers....but a DC curent will produce a level hum.

RedGTiVR6

http://www.350z-tech.com/zwiki/Tutor...plifier_Tuning

Please tune your amps properly first.

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supraman22

I had this problem with my audio too. Come to find out it was bad pre outs on the cd player. id check that out, it could either be that or like a few have said make sure your audio wires are on a different side of the car as your power wires. You can get nasty engine noise if you cross them.

88bonneville

if you sand the paint of a spot on the car completly and then ground the wire back you should loose all extra ground noise

88bonneville

sand all the paint off the spot where your ground is. and if that doe=nt work. tru=y using a different spot or a bigger ground wire.

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RedGTiVR6

88 - why the double posts?

and sanding down the paint won't always solve the problem.

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Ralphh85

i have never ever had this problem before and have had many different set ups in different cars.

the negetive of the amp and psu input are both soldered to the main 16mm2 cable which runs from battery in boot to the engine int he front. so a very good earth connection.

also the amp is right next to the pc, with only a 1m jack to phono cable connecting them so should be good connection there to?!

cheers to thoes trying to help
Ralph

RedGTiVR6

tuning your amps is crucial. I did not say that it was a ground issue, never mentioned such a thing.

If your gains are turned up too high you will experience the exact same issues as you are reporting.

Having a pinched wire will cause this problem as well.

I'm not sure why your against tuning the gains on your amps?

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Ralphh85

not against it, very far from it, i read that last night and its pretty much what i do but i have only played music i know as have not had the WAV files there.

either way i was only wondering if anyone had had a similar problem, or if anyone had grounded pc power to the amps negetive as i thought that might be the prob.

other than the slight humming it sounds very good

Ralph

cbevis

so...just a slight humming? how is your draw on the alternator? Think you might be pulling to many amps from it?

Now that you mention it...I was having a similar problem when I put in my PC...I originally though it may just be the fact that I'm using a 3.5 head phone jack as the connection because it only happens when I'm listening to WMP....3,5 jacks are not really the best in terms of feedback prevention...

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