technical question use of mic without parabola and gain

["uskroeger" uskroeger]

Hi,
I recently tried my Telinga Twin Science mic without the parabolic
reflector, and discovered that I could turn of the gain on the
recorder to past 75% without getting hiss.  Using the dish if I turn
the gain past 30% I get lots of hiss that also shows up in the sound file.
This is using the FR-2LE.  I have not tried it with the PMD-671.
Can anyone explain why this is?
I'm starting to question the use of the dish, as I was able to record
distant owls without it by turning up the gain.  The disadvantage is
that the omni cartridge picks up way more irritating sound, like a
distant motorcycle.

Thanks

Bernhard Kroeger
Nevada City, California