[sdiy] Shielding

[harry]

If you can use the balanced input as Don suggested in his post... that would
be the equivalent of "breaking the grounds" at that point.

I have never had much luck lifting an audio ground... It usually makes the
noise worse, as the other "ground" in the loop is usually a shitty one.

H^) harry

deknow wrote:

> wouldn't it make sense to lift the audio grounds between the mackie and the
> event card???
>
> deknow (who doesn't think the above will electrocute you, but doesn't know
> for sure).
>
> ----- Original Message -----
> From: harry <harrybissell at prodigy.net>
> To: Ingo Debus <debus at cityweb.de>
> Cc: <synth-diy at dropmix.xs4all.nl>
> Sent: Saturday, December 01, 2001 10:58 AM
> Subject: Re: [sdiy] Shielding
>
> > Hi Ingo....
> >
> > I'd be more suspicious of the card itself. A lot of cheapie sound cards
> were
> > not designed for high quality audio use.  Maybe 50dB signal to noise is OK
> > for a video game, but not an album !
> >
> > It would be easy to cheat the ground on the computer (2 to 3 wire plug
> adapter)
> > and find out.  If it goes away, its ground loop and you can buy the
> isolation
> > transformer (I paid $50 new for a stereo unit from ebtech). I bet the
> noise remains.
> >
> > H^) harry
> >
> > Ingo Debus wrote:
> >
> > > Moho Disco wrote:
> > > > Currently I'm just using the laptop's crappy internal soundcard, which
> > > > is wired directly into my Mackie 1604vlz.  A laptop adapter for my
> > > > Layla24 sound card should be arriving Monday, and I'm *praying* that
> > > > it does not exhibit the same symptoms.
> > > >
> > > > >If you remove all the wires, does the noise stop ?  (the idea is if
> the noise
> > > > >stops... it is being conducted by some wiring, not through the
> air...)
> > > >
> > > > Yep, the noise stops when I disconnect the cables from the computer
> > > > to the mixer.  It is most definitely being conducted through a wire...
> > > > But it doesn't matter what wire I use, they all transmit it.
> > >
> > > Like Theo obviously suspects too, this is most likely a ground loop
> > > problem. A friend of mine had that prob too with a Mackie mixer. It's
> > > difficult to disconnect signal ground from protective earth in these
> > > mixers without affecting electrical safety. All jacks are connected
> > > directly to the case as well as the power transformer, power switch and
> > > so on. An option is re-building the mixer's power supply into an
> > > external case (larger DIY project). Another option is using DI boxes or
> > > isolation transformers in the audio pathes between mixer and computer.
> > > I don't know the Layla card, if it has assymetrical (unbalanced)
> > > ins/outs the problem most likely won't go away :-(
> > >
> > > Ingo
> >
> > --
> > Jihad Terrorism Conspiracy New World Order
> > Revolution Black Helicopters Freedom of
> > Speech First Amendment Rights: Carnivore Bait
> > go ahead and READ my e-mail I have nothing to
> > hide... how about YOU ???
> >
> >
> >

--
Jihad Terrorism Conspiracy New World Order
Revolution Black Helicopters Freedom of
Speech First Amendment Rights: Carnivore Bait
go ahead and READ my e-mail I have nothing to
hide... how about YOU ???