Issue 6, September 2004
Model 50/51 User Guide
Page 34
Studio Technologies, Inc.
Input Level and the Talent Amplifiers
Optimal performance of the Model 35 and
Model 38 Talent Amplifiers depend on the
headphone source signal levels being at
approximately the nominal input level,
either –10dBV or +4dBu, depending on
the configuration. The headphone volume
is adjusted only by the level controls on
the talent amplifiers. If the selected head-
phone source signal level is significantly
less than nominal, the talent amplifier will
simply not be able to create the maximum
volume in the headphones. While there is
some gain in the talent amplifiers, optimal
performance still requires an input close
to nominal.
The Model 38 Talent Amplifier can also
exhibit reduced performance if the level
of the headphone source is significantly
“hotter” than nominal. The entire system
has plenty of headroom, but maintaining
proper signal levels, as usual, is important.
If the source selected for headphones has
an average level that is excessive, a small
amount of bleed-through can be heard
with the Model 38’s cue mix level control
set fully counterclockwise. Instead of hav-
ing no sound in the phones, a bit of sound
can be heard. This is not a design prob-
lem; the Model 38 has a sensitive pream-
plifier section which doesn’t like excessive
excursions in the left channel modulation
of the +23Vdc signal. The Model 38’s
power supply can reject the left channel
modulation within the design parameters,
creating a clean reference voltage for the
stereo preamplifier. Modulation levels out-
side the design parameters show up in the
reference voltage!
Communication Switch Noise
During field trials of the StudioComm
components one item came up for
discussion concerning “thumps” in the
communications functions. A brief dis-
cussion may be useful. Electrically the
Model 50 and Model 51 electronics that
support the communications functions
are quite quiet, not adding appreciable
“clicks, pops, or thumps.” Software time
delays are even added to minimize noise
when the buttons are pushed. Mechanical
noise being picked up by the Model 51’s
microphone can be an issue. If the talk
to studio, talk to phones, or slate buttons
are pushed using a relatively light touch
no objectionable noise will be generated;
pressing the switches with “gusto” will
cause mechanical noise to be transferred
into the microphone. While the Model
51’s microphone is of good quality, shock
mounting it was not possible using a cost-
effective method. The fact that the Model
51 is physically small and the buttons
must be relatively close to the microphone
adds to the difficulty. (Note that most all
recording consoles, both small and large,
share this condition.)
What are the options if the operator(s) of
your Model 51 choose to use a “heavy”
hand on the switches? Two are read-
ily available: external communications
switches and an external source of
communications audio. A connector on
the back of the Model 51 allows the con-
nection of external talk to studio and talk
to phones switches. Using external switch-
es can eliminate the transfer of noise into
the Model 51’s microphone. The Mic
Module connector on the back of the
Model 50 allows an external source of
communications audio to be substituted
for the signal provided by the Model 51’s
microphone. Using a microphone and
simple preamplifier (or microphones and
an inexpensive mixer) you can optimize
