[ardour-users] Short question concerning quality

Thomas Vecchione seablaede at gmail.com
Thu Jul 12 10:29:41 PDT 2007

On 7/12/07, Paul Winkler <pw_lists at slinkp.com> wrote:
> If so, you might try something like the Ebtech Hum X.  (But I don't
> know if they make a version for European plugs and voltage.)
Ugh NO.

DO NOT use the Hum X.  While with a discussion with someone that knows more
than me on the topic he conceeded it may be using a trick that might be
safe, there is no reason to use it really, and since they don't ever say
exactly WHAT it is doing, I would stay away from it.  The other person I was
talking to also mentioned that IF it was doing what he thought it was that
MIGHT be considered 'safe' it would not be considered safe in the EU due to
the voltage differences.

The probably most likely reason, that noise would improve on battery supply,
is due to a ground loop, and this is what EBTech market's their hum x for.
IF it IS a ground loop, the much better and safer way to handle it is to
isolate the audio signal reference grounds connected to the laptop, the best
way to do this is with a simple 1:1 transformer, though there are many
premade devices out there already to do this, eb tech even has some, though
because of their lack of material on the Hum X I stay away from them, ART
makes an inexpensive isolation transformer though I have no problem spending
money on.

Typically a ground loop will show up as noise that increases as you move the
mouse, or the HD spins up, and goes away when the laptop is unplugged.  Also
in general this will not be affected by the amount of signal coming into the
laptop(Though would be affected by unplugging the cable providing the ground
loop).  If this is the case, isolate the AUDIO grounds, NOT the AC grounds.
Much safer, and accomplishes the task rather well.

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