Another suggestion might be to remove any digital effects / processing
device from the signal chain upstream of the DL4, if any. If that makes
the whine go away, it would point to aliasing by the DL4 digitizer of any
not-so-high frequency spurious noise output from the digital effects
device.
Nic
----- Original Message -----
Sent: Tuesday, August 17, 2004 12:01
AM
Subject: Re: DL-4 hum/buzz when
half-speed overdubbing?
At 11:12 AM 8/16/2004, Greg House wrote:
>--- Nic
Roozeboom <Nic_Roozeboom@msn.com>
wrote:
>
> > This behavior (especially since both units exhibit
it) could be
> consistent with
> > a nearby noise source being
sampled and aliased into the audible
> spectrum. Have
> > you
recently added something to your setup or environment that radiates
> -
like
> > a monitor, something with a switched mode power supply (e.g.
computer) or
> > wireless link?
>
>My friend had terrible
noise problems with a DL4 on his pedalboard until he
>physically moved
it away from his power strip (which contained a couple
of
>warts).
I suspected the wall wart also when I heard this
story. A couple possibilities:
- Wall warts normally are not well
shielded and use low cost transformers
that radiate a lot of 60Hz hum.
Nearby devices that are also not well
shielded can pick up this hum and
make it part of the audio signal in
various ways. (as the other guys
noted.)
- Wall warts (and other types of power supplies) can generate
"common mode"
current. Normally a power supply should drive current out on
the power and
receive it back equally on the ground. Common Mode current
is driven out on
both, and finds some other path back to earth ground.
This can happen if
the wall wart is not designed well, or uses a cheap
unbalanced transformer,
or even with aging. This AC common mode current
might find that path to
earth through your audio cable grounds, in which
case you get hum and noise.
My suggestions would be: Try moving the dl4
away from nearby wall warts or
other power supplies as others suggested;
Try replacing the wall wart (or
using batteries to check if that is the
problem.)
kim
______________________________________________________________________
Kim
Flint
| Looper's Delight
kflint@loopers-delight.com
| http://www.loopers-delight.com
