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Re: Zoom H4 modification.

Subject: Re: Zoom H4 modification.
From: "oryoki2000" oryoki2000
Date: Sat Feb 17, 2007 4:03 pm ((PST))
Klas,

That's great news.  Will you offer the H4 with EM21 capsules for sale,
or sell the parts plus instructions so others can perform the
modification?

There's an active forum of Zoom H4 users at www.2090.com
They have identified the internal power supply as the source of
annoying preamp noises.  Apparently the preamp picks up RF
interference generated when the H4 draws power to periodically write
data to the flash memory card.

The forum participants have devised two fixes.

One approach is to use an external battery for power.  If input
voltage stays above 6VDC, the H4 does not generate the unwanted noises.
http://www.2090.org/zoom/bbs/viewtopic.php?t=3D7937

The second solution is to add capacitors to reduce noise when running
on the voltage provided by the internal AA cells
http://www.2090.org/zoom/bbs/viewtopic.php?t=3D7886

Of the two approaches, the external battery seems to result in better
recordings.  Plus there is no need to open the H4, which voids your
warranty.

H4 owners: Please verify that extraneous noises are reduced or
eliminated when recording on external power (AC power or external
battery).  Thanks!

--oryoki





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