Specifications

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as to avoid contact with it. Professional condenser microphones requiring
phantom power cannot be directly connected to a camcorder; a separate
phantom power supply is required.
•
If the camcorder is stereo, are there separate mono input jacks for the left
and right channels, or a single stereo input jack that feeds both channels?
If there are separate mono jacks, do they supply DC power.
Is a Transformer Necessary?
If the length of cable between the microphone and the camcorder will be 20
feet or less, all that is necessary is to use a cable with the appropriate connectors
and wiring. If the cable will be longer than 20 feet, however, a transformer will be
required at the end of the cable nearest the camcorder. The camcorder-side of
the transformer is typically equipped with a very short cable and a 3.5mm mono
or stereo connector. The transformer provides two benefits:
•
The transformer maintains a balanced connection between itself and
the microphone, minimizing pickup of hum and electromagnetic
interference and allowing for cable runs of up to 1,000 feet. (Longer
cable runs require a mixer or preamplifier to boost the microphone
signal up to Line level, about 1 volt.)
•
The transformer can boost the signal level slightly, which may be useful
when connecting a low-output microphone (or one used at a
considerable distance from the sound source) to a camcorder whose
microphone input is not very sensitive. The amount of boost (called
“gain”) that the transformer provides depends on the ratio between its
input and output impedances, as well as the ratio between the
transformer’s output impedance and the camcorder’s input impedance.
Typical transformers provide between 6 dB and 12 dB of gain.
Connecting a Mixer to a Camcorder
The output of a mixer can be connected to a camcorder’s mic input if the
mixer has a mic level output. If the mixer only has a line level output, its level
must be attenuated (decreased) by approximately 50 dB to prevent
overloading of the camcorder’s microphone input circuitry. A device called
an attenuator
is used for this purpose. Some attenuators offer a choice of
settings to provide varying amounts of attenuation. Some camcorders have
a line level input in addition to the mic input.
If the cable run from the mixer to the camcorder is longer than 20 feet, a
transformer is re-quired, as discussed previously. Note: The mixer must
have a mic level output, OR the transformer must be capable of handling a
line level signal from the mixer without being overloaded (most cannot).