Studio Technologies 210 2012 - Manual (Page 16)

Issue 5, September 2012 Model 210 User Guide
Page 16 Studio Technologies, Inc.
An LED indicator is provided as an aid
in correctly setting the gain of the micro-
phone preamplifier. Red in color, this LED
is located adjacent to switch assembly 1.
It is visible by observing the bottom of the
Model 210’s enclosure when the security
plate has been removed. Technically, this
red LED lights whenever the compressor
circuitry is controlling the dynamic range
of the signal coming from the microphone
preamplifier. The threshold is set to be
2 dB above the Model 210’s nominal in-
ternal operating level. So a good “rule of
thumb” is to adjust the gain of the micro-
phone preamplifier such that the compres-
sor active LED lights (“flashes”) when the
connected microphone is sending signal
peaks. During normal operation the LED
should not remain fully lit when audio is
present on the mic input.
It’s important to remember that the com-
pressor active LED is used to assist in set-
ting the gain to the optimal value. It doesn’t
necessarily indicate that the main output’s
signal is being compressed. Unless specifi-
cally configured to perform otherwise, the
output of the compressor is only used for
the talkback output.
It’s expected that the 20 and 60 dB gain
settings will not often be used. But there
are always exceptions and that’s why they
were included. It’s possible that with a very
“hot” microphone, such as a phantom-
powered condenser-type, 20 dB of gain
could be correct. It’s also possible that a
microphone with a very low-level output,
such as a ribbon-type, would need 60 dB
of gain. But in general, the 30, 40, and
50 dB gain settings will serve most
applications.
Note that if no gain switch is set to its
active (on) position the preamplifier
will operate at unity (0 dB) gain. This is
provided for compatibility when line-level
signals need to be connected to the
microphone input. But with a microphone
connected as the input source one should
never use the 0 dB setting. The issue is
that with no gain added to the microphone
input signal, the relative noise floor on the
main and talkback outputs will be much
too high. These outputs are designed for
handling line-level signals, expecting to
receive the output of the mic preamplifier.
Relay Contact Mode
Switch SW1-7 configures the operating
mode of the relay contact function.
Figure 5. Relay contact mode switch settings
Two modes are available:
• Follows main output status: In this mode
the relay contact will follow the status of
the main output. Specifically, the relay
contact will close (short) whenever the
main output is active.
• Follows talkback output status: In this
mode the relay contact will follow the
status of the talkback output. Specifi-
cally, the relay contact will close (short)
whenever the talkback output is active.