Re: Laptop recommendations

[<biz-looper@groovetronica.com>]

The sound is >not< 60 cycle hum. It's noise emanating from the computer's
power supply.

This isn't your usual quiet computer disk drive 'gurgles' - it's a
screeching loud enough to drown the audio signal.  We've tried ground
lifts - they don't make any difference.

bIz

> --- biz-looper@groovetronica.com wrote:
> >
> > Because the audio signal from the USB port is analog, and shares the
ground
> > over the USB connection with the laptop and its power supply, so once
the
> > audio gets out of the digital domain, it gets messed up.
> >
> > I've tried isolating the laptop ground from the mixer, by severing the
> > ground on the audio connection between the two, but no luck. Perhaps
> > severing the ground of a USB card attached to the laptop? Since the 
>card
> > would be grounded through the audio cables, I don't see any danger of
> > damage, but I don't have the electrical engineering knowledge to know 
>if
> > this would work.
> >
> > Works fine with headphones though...
> >
> > ----- Original Message -----
> > From: "mark" <sine@zerocrossing.net>
> > To: <loopers-Delight@loopers-delight.com>
> > Sent: Wednesday, April 02, 2003 11:03 AM
> > Subject: Re: Laptop recommendations
> >
> >
> > > That doesn't seem to make any sense to me... USB is digital data.
Gets
> > > fed into a converter which then sends an analog signal to a
> > > preamp/mixer/poweramp stage.  I'm unaware as to how the laptop could
> > > affect the D/A converter.  The digital signal would have to have the
> > > noise embedded in it... no?  Does anyone know about this?  I cleared
up
> > > a noisy internal sound-card on my mac by just putting a transformer 
>on
> > > the output.  (it's cheap you can buy them at radio shack, they're 
>made
> > > for car stereos but work fine for this problem)
> > >
> > > Mark
> > >
> > > On Wednesday, April 2, 2003, at 10:36 AM,
> > > <biz-looper@groovetronica.com> wrote:
> > >
> > > > a horrible and unavoidable hum occurs
> > > > when you plug them into any kind of mixer or power speakers. There
is
> > > > no
> > > > solution - it even happens with USB audio.
> > >
> > >
> > >
> >
>
>
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