Model 50/51 User Guide
Issue 6, September 2004
Studio Technologies, Inc.
Page 35
the sound quality and location of the com-
munications mic(s). With the Model 51’s
microphone no longer in use, the switch-
es can be “beaten on” with no impact on
communications audio. For details on
how to implement external communica-
tion switches or to use the Mic Module
input refer to other sections in the Ad-
vanced Installation Topics section of this
user guide.
Power Amplifier Input Sensitivity
Optimum StudioComm performance is
obtained when the input sensitivity of the
control room and studio power amplifiers
are adjusted to match the Model 50’s out-
put level. With normal, but loud, listening
levels you should find the level potentiom-
eters on the Model 51 to be set to about
11 or 12 o’clock. If you find that you don’t
have to turn up the Model 51’s controls
that high, reduce the input sensitivity of
the power amplifiers. Most power ampli-
fiers have controls on their inputs to allow
easy adjustment of the input sensitivity.
Control Room and Studio Output
Transient Protection
Unique to the Model 50 Central Control-
ler is a power up/power down transient
protection feature. This limits the chance
of damage to the control room and stu-
dio loudspeakers during the time when
AC mains voltage is connected, discon-
nected, or has significantly changed from
nominal. A combination of hardware and
software are used to monitor one of the
power supply “rails.” Until the power sup-
ply exceeds 81% of its nominal voltage,
electromechanical relays maintain a short
circuit condition on the control room A
and B outputs and the studio outputs.
After a one-second delay the relays are
released to function normally. Whenever
the power supply drops below 79% of its
nominal voltage, the relays immediately
go to their mute state. During testing it
was found that upon power up the outputs
remained very quiet; during power down
a moderate “tick” was the worst that
was heard.