When multiple speakers are to be connected to either or
both outputs, the combined load impedance must be calcu-
lated. The load must be connected to the appropriate im-
pedance tap. Use this table to aid in selecting the correct
impedance match:
Load Load
impedance impedance
in ohms Connect tor in ohms Connect for
1.6 to 3.2 2 ohm output 6.4 to 13 8 ohm output
3.2 to 6.4 4 ohm output 13 and up 16 ohm output
If a load impedance is used that is lower than the output
impedance tap, then reduced power and possible distortion
w i l l result. If a load impedance is used that is higher t h a n
the output impedance tap, then neither the signal nor the
amplifier will be harmed but the power available is limited.
FOR STEREO OR TWIN AMPLIFIER CONSTANT VOLTAGE
OPERATION:
For output
voltage of Connect for
25 volts 8 ohms
FOR MONOPHONIC CONSTANT VOLTAGE LINE
OPERATION;
For output
voltage of Connected for
25 volts 4 ohm output (mono)
For multiple speaker operation, run separate leads from
each
speaker
to the amplifier.
Should the MODE SWITCH be left in the STEREO position
and the output transformers be strapped for a monophonic
load, one channel w i l l attempt to drive the other and cause
circulating currents and overheating. Be certain that the
MC 2120 is never operated in the stereo mode with the
outputs connected for monophonic operations.
AC POWER
The MC 2120 operates on 120 volts 50/60 Hz. The a u x -
i l i a r y AC OUTLET on the MC 2120 is not fused or switched.
MONOPHONIC OR SINGLE CHANNEL OPERATION
When the MC 2120 is used as a monophonic or single
channel power amplifier the two channels are combined to
produce output up to 240 watts. The outputs must be tied
together at the appropriate load impedance tap. In connect-
ing a load to the MC 2120 for single channel operation
connect the common side of the load to the LEFT CHANNEL
OUTPUT terminal marked COM., the other lead is c o n -
nected:
If the speaker
or load
impedance is
1 ohm
2 ohms
4 ohms
8 ohms
The hot side
of the line is
connected to
Left 2
Left 4
Left 8
Left 16
Connect a jumper
wire between
Left 2 and Right 2
Left 4 and Right 4
Left 8 and Right 8
Left 16 and Right 16
Do not connect unequal impedance taps together
If the load impedance is between a n y of the above fig-
ures, select the best impedance match from;
Load Load
impedance impedance
in ohms Connect for in ohms Connect for
0.8 to 1.6 1 ohm output 3.2 to 6 4 4 ohm output
1.6 to 3.2 2 ohm output 6.4 and up 8 ohm output
5
www.freeservicemanuals.info
5/10/2017
Digitized in Heiloo Netherland
