F
IT CONNECTIONS
._I__
. __..
_.
Models
CT35 & CT100
All models
All
All
All
Speaker Line
Unbalanced
Balanced
Unbalanced
Balanced
Unbalanced
Balanced
25V Unbalanced
25V Balanced
25V Balanced, CT gnd.
70V Unbalanced
70V Balanced
Terminal Connections *
and COM 1
and COM 1
and COM 1
and COM 1
and COM 1
and COM 1
25V and COM 1
25V and COM 1
25V and COM 1
Pins 2 and 3
Pins 2 and 3
Other Connections
Close link between COM 1 and GND
Open link between COM 1 and GND
Close link between COM 1 and GND
Open link between COM 1 and GND
Close link between COM 1 and GND
Open link between COM 1 and GND
Close link between COM 1 and GND
Open link between COM 1 and GND
Connect jumper between 25V CT and GND
Open link between COM 1 and
GND
Connect impedance selector to COM 2
Connect jumper between COM 2 and
GND
Connect impedance selector to COM 2
*Also see text under “Output Connections”
ROOM EQUALIZATION:
With speakers connected and
one microphone in normal operating location, turn ampli-
fier on and proceed as follows:
1. Connect microphone to appropriate MIC input of
amplifier.
2. Set all five acoustic filter controls to zero (center
position).
3. Turn MIC volume control half-way up and the three
other MIC volume controls to zero.
4. Advance MASTER volume control slowly until
feedback is heard.
5. Note the frequency of the feedback tone, and de-
termine which of the five selected frequencies on the
Acoustic Equalizer is closest to it.
6. Move the control determined in Step 5, above,
down toward minimum until feedback disappears.
7. Advance MASTER control again and note whether
feedback is heard at another frequency.
8. Adjust the appropriate filter controls until this
feedback disappears.
9. Continue to advance MASTER control and adjust
individual filter controls until MASTER control is at maxi-
mum setting, consistent with a stable output without
feedback at any frequency.
10. Output level reduced because of attenuating one
frequency may be partly restored by boosting the adjacent
frequency filter control toward maximum.
If feedback is
nor
a problem, the controls
should be used to improve the voice quality
and intelligibility of the paging system. In
most cases, the 10 kHz and 80 Hz controls
should be placed in minimum position while
the 300 Hz, 1 kHz and 3 kHz should be
moved toward maximum for improved
presence. Each system, depending on the
speakers used and room acoustics, will re-
quire someexperimentation with the controls
for optimum results.
11. Note and record the settings of the individual filter
controls and the MASTER control. These settings are
generally applicable to all four MIC input channels, if the
microphone remains in the same position.
12. If the position of the microphone is changed or
additional microphones are used, some adjustment in the
feedback controls may be necessary.
COMPRESSOR LIMITER:
The COMPRESSION control is
used to provide relatively uniform output from the am-
plifier regardless of variations in the input levels. This is
particularly important in speech applications, where a
microphone may be used by a number of people with
varying voices and microphone techniques. It is also useful
for musical programs, particularly when handling back-
ground music.
The COMPRESSION control is turned clockwise to the
higher numbers to reduce the output range for a given
variation in input range. Turn the control counter-clockwise
to lower numbers to increase the output range. To remove
compression and restore the normal full range of the
amplifier, turn the control fully counter-clockwise to zero.
To determine the optimum setting of the COMPRES-
SION control for speech applications, proceed as indicated
below. For music, the setting will generally be lower than
for speech.
Set the COMPRESSION control fully counter-clockwise
to zero position. Set the MASTER volume control to the
highest level likely to be required. Use a level setting’that
will permit you to pick up clearly spoken inputs in a low
voice at a distance of three feet on axis from the micro-
phone. However, do not set the volume level so high as to
produce feedback or howling.
Then, speaking in a loud voice directly into the micro-
phone, turn the COMPRESSION control clockwise to the
point where the output of the amplifier is reduced to the
same level as obtained above. The MASTER control can be
used to vary the over-all volume without upsetting the
COMPRESSION adjustments.
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