Re: [LAU] OT interference / grounding problems

On Wed, 18 Feb 2009 04:04:57 +0000
pete shorthose <zenadsl6252@email-addr-hidden> wrote:

> On Tue, 17 Feb 2009 21:02:02 -0500
> carmen <_@email-addr-hidden-your.name> wrote:
>
> > > It may just be that it took the introduction of better quality gear for me to hear the effects above the usual
> > > din but then these static like snapping noises are very distinct.
> >
> > the suggested ground topology is a star or radial shape,
> >
> > path to ground from each device is never thru another device, and potentials are as similar as possible
>
> I have an approximate radial setup but the mixer would be the hub. Thing is and as I said, I've tried to
> use some of these things in isolation. (only the zoom H4 or only the mixer, both have integral monitoring so
> no need for an amp or pc) but I still see it. (well, hear it)
>
> > do you have a metal radiator pipe? or barring that a 3 prong wiring?
>
> Ah, moved the radiator recently. I could run a cable tho.
>
> > are you using 2-pronged gear or 3? it may be that your house ground is not properly grounded (bad)
>
> well AFAIK, the house is grounded and being in the UK the sockets are all 3 pronged. that said, I'm pretty sure
> that non of them use the 3rd prong. (plastic tab instead of a metal prong or 2 core flat cables)
>
> > or strong induced currents from close 60hz mains cabling (perhaps even 120v is enough at a close distance)
> >
> > i use alligator-clipp terminated cables, to grip onto the metal box around a USB port,
> >
> > then hook that to the negative battery terminal of my amp. then tap this wire and connect to the radiator pipe
> >
> > (shuts shit up pretty good).........
>
> Cool, ty. I'll try a few things. I'll also say goodbye now in case I'm found dead tomorrow with a spectacular new
> hairstyle.

Problem solved I think. I tried using someone's Dell XPS laptop (almost identical to my 9400) and the problems
disappeared. Indeed, noise levels dropped vs using the devices in isolation. The difference? The 9400 has
a 3 core earthed AC adaptor and non of my other gear is earthed at all. After googling around I also discovered
that this is why I've been getting electric shocks from the metal parts on my 9400 so hopefully I can get an earthed
AC adapter for this laptop.

pete .
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
Received on Fri Feb 20 12:15:03 2009