Inverter + hum + external sound card

lazarus · 02-16-2004, 01:04 PM

my inverter causes the psu in my car instal to hum quite badly. I'm currently using the onboard sound and the hum is been passed through to it so i get really nasty background hum. the noise isn't been caused by the engine running as it is present when the engine isn't running (that and a drive a diesel) i've tried various power supplies but all hum ( they dont need to be hooked up to the main board to be heard humming, just need power from the inverter)

now for the question. would using an external usb sound card get round this? i presently don't have the cash to buy a dc-dc psu (though i do want to go down that route) nor do i have the cash for a full sine wave inverter.
has any one had experience with this?

god_of_cpu · 02-16-2004, 01:19 PM

I had a real bad hum coming from my laptop hooked up to the inverter and only when the inverter was on. I tried an external sound card on it and it didnt help at all. It still had the hum. I never solved the problem on that car.

Quote: Originally Posted by lazarus

my inverter causes the psu in my car instal to hum quite badly. I'm currently using the onboard sound and the hum is been passed through to it so i get really nasty background hum. the noise isn't been caused by the engine running as it is present when the engine isn't running (that and a drive a diesel) i've tried various power supplies but all hum ( they dont need to be hooked up to the main board to be heard humming, just need power from the inverter)

now for the question. would using an external usb sound card get round this? i presently don't have the cash to buy a dc-dc psu (though i do want to go down that route) nor do i have the cash for a full sine wave inverter.
has any one had experience with this?

hijinks21 · 02-16-2004, 01:19 PM

probably not.. ground your setup first. Make sure your inverter is grounded to your car frame and then ground your PSU to the same spot as the inverter to the frame. Try that first. That should get ride of it all.. but if some still is around ground your motherboard to that spot also

lazarus · 02-16-2004, 01:27 PM

Quote: Originally Posted by hijinks21

probably not.. ground your setup first. Make sure your inverter is grounded to your car frame and then ground your PSU to the same spot as the inverter to the frame. Try that first. That should get ride of it all.. but if some still is around ground your motherboard to that spot also

psu is grounded as is the inverter (both to the same point). i dont think this is a grounding issue. the psu can be heard to be buzzing. this is the same for every psu i've tried. they dont need to be installed in any thing, just hook up the power and they buzz. i've tried 4 different one now.

there is also a ground loop isolator installed.

none · 02-16-2004, 01:30 PM

Quote: Originally Posted by lazarus

psu is grounded as is the inverter (both to the same point). i dont think this is a grounding issue. the psu can be heard to be buzzing. this is the same for every psu i've tried. they dont need to be installed in any thing, just hook up the power and they buzz. i've tried 4 different one now.

there is also a ground loop isolator installed.

That is a bad inverter - cheap and/or dying.

lazarus · 02-16-2004, 01:33 PM

Quote: Originally Posted by none

That is a bad inverter - cheap and/or dying.

cheap yes, though dying i dont think. I have 2 inverters (not hooked up at the same time) the 300 watt i'm currently using and a 150 watt, both have the same effect.

greenglo · 02-16-2004, 01:33 PM

What brand are your inverters?

lazarus · 02-16-2004, 01:46 PM

both are "Nikkai"

greenglo · 02-16-2004, 01:49 PM

I'm no expert on inverters, but I think it wouldn't hurt to buy a different brand of inverter just to try it out.

Defiler · 02-16-2004, 04:35 PM

Get one of these http://www.radioshack.com/product.as...5Fid=61%2D2420 it took all the noise out of my setup. Also, don't get the cheaper ones as they don't have the noise suppression this one does.

lazarus · 02-16-2004, 06:41 PM

Quote: Originally Posted by Defiler

Get one of these http://www.radioshack.com/product.as...5Fid=61%2D2420 it took all the noise out of my setup. Also, don't get the cheaper ones as they don't have the noise suppression this one does.

cheer dude. i'll have a look about and see if i can find an eqivelent here in the uk

lazarus · 02-17-2004, 07:35 PM

Got the chance to test with a different inverter and an external usb sound card. neither had any effect on the buzzing. looks like my best bet now is going to be to build the sproggy psu. just put in my sample order for the maxim IC's as soon as they turn up i'll get the semi kit ordered. (mastero if you're reading this, you should be getting an order through soon

)

Tidder · 02-17-2004, 07:53 PM

I had the same problem. Couldn't get rid of the noise at all. Finally (i know this sounds freakin' stupid) after I grounded my psu, my inverter, my lcd, my motherboard directly, I finally decided to try and ground the ground of my audio out. That did the trick. Don't understand it really, but it sounds great!

none · 02-17-2004, 09:26 PM

Quote: Originally Posted by lazarus

Got the chance to test with a different inverter and an external usb sound card. neither had any effect on the buzzing. looks like my best bet now is going to be to build the sproggy psu. just put in my sample order for the maxim IC's as soon as they turn up i'll get the semi kit ordered. (mastero if you're reading this, you should be getting an order through soon

)

Good plan.

MiniRX7 · 02-17-2004, 10:38 PM

AWESOME!..

I am going to buy one of those.. and try it.. I got all sorts of noise from my invertor!

ED