Strange problem

**Toehead** · 07-30-2006, 12:15 AM

Ok. The inverter is buried, so I will get on that tomorrow. I will also try to ground to chassis the negative of the laptop adapter.

**Will Albers** · 07-30-2006, 11:32 AM

Mine does it with DC to DC power supplies. Its normal.

**Will Albers** · 07-30-2006, 11:33 AM

Originally Posted by Toehead

Hmmmm.. For a ground loop there must be a path to ground... The only direct way , since the plug goes through the inverter, seems to be through the usb or rca cables..... If I ground the laptop properly, the ground loop should be eliminated, correct?

nope, you could be grounded perfectly and you will still get the noise. Seriously, there is nothing wrong. think of it like when you touch your fingers to the tip of the RCA, it causes a buzzing. Its the sound card touching the tip of the wire with its fingers =)

**Toehead** · 07-30-2006, 11:57 AM

Ok, today I took the case apart and properly grounded the laptop. The noise is gone! If I turn the amp up to max i can barely make it out, and at normal volume you cant hear it at all. You were right,,, the soundcard does seeem to switch to ground when it is off... the problem was it was grounding through the USB shell, the only available ground, and a very unclean one at that. Now that it has a true ground, it sounds MUCH better!. Thanks for all your help guys.