When a tape recorder is plugged into the front
jacks all the facilities normally associated with
TAPE 2 on the rear panel are automatically transfer-
red to the front panel jacks.
CONNECTING TO POWER AMPLIFIERS
Connect the jacks labeled "OUTPUTS MAIN" to
the input of a stereo power amplifier. The Left MAIN
jack is connected to the left amplifier input jack. The
Right MAIN jack is connected to the right amplifier
input jack.
Cables are supplied to interconnect the C 29 to
the power amplifier. Longer cables can be used if
needed. The length of the cable is limited by the ca-
pacitance of the cable. The total cable capacitance
must not exceed 1,000 pF. For instance: cables with
a capacity of 25 pF per foot may be 40 feet long. 13.5
pF per foot cable may be 75 feet long. The input im-
pedance of the amplifiers should be 10k ohms or
greater.
A second pair of MAIN OUTPUT jacks have been
supplied to feed a second power amplifier. In the
event it is desired to tape record after the tone, filter,
and volume controls the second set of OUTPUT
MAIN jacks can be connected to the tape recorder
input. The controls are then all available to control
the signal before recording. Remember, any change
in the setting of the controls will change the pro-
gram to the tape recorder. Since the recording signal
available at the OUTPUT MAIN is much higher than
the output available from the OUTPUT TAPE 1 or
TAPE 2 jacks, it will be easy to over-load the tape
recorder input. In this mode of operation, it will not
be possible to monitor from the tape recorder via the
TAPE MONITOR pushbuttons while feeding the
recorder from the OUTPUT MAIN jacks. Depressing
the TAPE MONITOR pushbutton will disconnect the
program source and may cause feedback oscilla-
tion.
SPEAKER CONTROL RELAY
To control loudspeakers by use of SPEAKERS 1
and 2 pushbuttons on the front panel an accessory
Mcintosh SPEAKER CONTROL RELAY is needed.
Plug the special cable from the SPEAKER CONTROL
RELAY into the C 29 back panel SPEAKER CON-
TROL RELAY receptacle. In addition to loudspeaker
connections and switching, the SPEAKER CON-
TROL RELAY has two AC power outlets that provide
additional capacity of 2400 watts. Use these outlets
to supply AC power to amplifiers or other com-
ponents whenever the total load to be switched by
the C 29 exceeds its rating of 600 watts.
CONNECTING AC POWER
The preamplifier AC power cord is plugged into a
120 volt 60 Hz wall outlet.
There are two types of AC power outlets on the
back panel: four black and two green.
The green AC power outlets are on at all times.
Plug the AC power cables from the turntable into the
green TURNTABLE power outlets on the rear panel.
The black outlets are switched on and off when the
preamplifier is turned on or off. These are intended
for power amplifiers, equalizers and other ac-
cessories up to 600 watts total capacity.
The POWER ON pushbutton shares AC power
control with the AC power switch on a turntable,
through a current detecting switch circuit. On the
rear panel the TURNTABLE AUTO/MANUAL switch
selects the mode of operation. When the switch is in
the AUTO position and a turntable is plugged into
one of the green AC power outlets, the AC power to
the preamplifier and to the black AC power outlets
can be controlled by the turntable on/off switch.
When AC power to the turntable is turned on, auto-
matically the preamplifier and the switched black
AC power outlets are turned on. The system will re-
main on until the turntable is turned off. The POWER
ON pushbutton controls the AC power for any
source other than the turntable.
In the MANUAL position only the POWER ON
pushbutton will turn AC power on or off.
Some turntables have electronic circuits that
draw current all the time. To use these turntables the
AUTO/MANUAL switch must be in the MANUAL
position. With the AUTO/MANUAL switch in the
MANUAL position, AC power to the system will be
controlled by the front panel POWER pushbutton only.
The green AC power outlets are protected with a
one ampere fuse. Any increase in the value of this
fuse will affect the protection of the sensing circuit
and can cause damage.
CONNECTING PROGRAM SOURCE GROUNDS
A single GROUND post is provided to which
grounds for turntables, record changers, tape decks,
etc. are connected. To prevent hum pickup, the left
and right program cables and the ground wire from
that source should be wound or twisted together.
Make sure the ground wire does not make any con-
nection to the shields of the left and right program
cables between the source and the input of the
preamplifier.
FUSES
A 1.0 AMP fuse protects the preamplifier circuits.
The fuse does not protect additional equipment con-
nected to the back panel AC outlets.
The green AC power outlets are protected with a
one ampere fuse. Any increase in the value of this
fuse will affect the protection of the sensing circuit
and can cause damage.
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