Specifications

connects the composite to both left and right output
circuits.
L + R TO L: Connects the left plus right program to
the left output circuit only.
L + R TO R: Connects the left plus right program to
the right output circuit only.
CONCENTRIC CONTROLS
LOUDNESS
The LOUDNESS control, (small center knob), provides
frequency response contoured to compensate for the
behavior of the human ear at lower listening levels. At
the fully counterclockwise position, the loudness contour
is electrically flat. As the control is turned clockwise,
selected frequencies increase in the correct proportion
for proper listening at softer volume levels. The
frequency balance is not affected by changes in the
volume control settings. First adjust the volume for the
desired listening level. Then adjust the LOUDNESS
control for the preferred compensation.
BALANCE
The BALANCE control, (large outer knob), adjusts the
volume of the channels relative to each other.
L, (left): Turning the control to the left accents the left
channel by reducing the volume of the right channel.
R, (right): Turning the control to the right accents the
right channel by reducing the volume in the left channel.
At the center detent position both channels are equal.
COMPANDOR SELECTOR
The outer COMPANDOR knob can be set to EXPAND,
OFF, or COMPRESS. In the center OFF position, the
Compandor System is switched out of the circuit. When
the Compandor is not used, the selector should be
placed in the OFF position.
RATIO CONTROL
The inner RATIO knob is used to control the amount
of expansion of compression.
PUSHBUTTON SWITCHES
POWER
The red button turns the C40 on. The panel will
illuminate to indicate the program source that has been
selected and special operating modes.
SPEAKER 1 AND 2
The SPEAKER 1 and 2 buttons switch on or off the
program signals at the SWITCHED 1 and 2 AUDIO
OUTPUT jacks on the C40 rear panel. When the
optional SCR3 speaker relay is being used with the C40,
the pairs of speakers connected to the relay terminals
1 and 2 will also be switched on or off. The LED
indicators will light to show which switched output has
been selected.
MUTE
Should you desire to silence the system briefly, touch
the MUTE button. A red indicator next to the MUTE
button will light, and the program will be silenced at the
MAIN, SWITCHED 1 and 2 outputs. Press the button
again to un-mute. The mute does not affect the tape
outputs.
PROCESSOR
The PROCESSOR button switches the external
LISTEN processor in or out. If a processor is not
connected there is no action and the indicator LED does
not illuminate. However, if a processor is plugged into
the jacks the RED LED indicates when the processor is
in the circuit.
REC MONITOR
The RECord MONITOR button switches the LISTEN
circuit to the program material that has been selected
by the RECORD input switch. This allows one to
instantly MONITOR the signal going to the tape
recorders. If one wishes to listen to the recorded signal
on a three head tape recorder, he must leave the REC
MONITOR button in the normal (OFF) position and select
the desired TAPE position on the LISTEN input switch.
REC COMPAND
The REC COMPAND pushbutton switches the
COMPANDOR circuits between the LISTEN and RECORD
program lines a red light emitting diode (LED) illuminates
to indicate when the circuit is connected to RECord.
REC EQUAL
The REC EQUAL pushbutton switches the
EQUALIZER FREQUENCY controls between the LISTEN
and RECORD program lines. A red LED illuminates to
indicate when the circuit is connected to RECord.
HEADPHONE JACK
The C40 has sufficient built-in power capability to feed
a low impedance dynamic headphone connected to the
HEADPHONE jack.
MclNTOSH LABORATORY INC., 2 CHAMBERS STREET, BINGHAMTON, NEW YORK 13903
C40 Product Preview Page 4