REAR PANEL CONNECTIONS AND CONTROLS continued
Correct Speaker Polarity is Important
As you connect the speaker wires, you can see that the insulation on one of the two wires in
each pair has either printing or a raised ridge. The marking lets you know which wire you con-
nected to the positive speaker terminal at its other end.
Make sure the + wire you attach to each Model 2125 + speaker terminal is attached to the +
terminal of the speaker for that channel.
Bridging Switch: Stereo - Mono
The Model 2125 power should always be turned off before moving this switch.
For normal operation the Bridging switch must be set to Stereo.
For bridged mono operation, set it to Mono.
Note:
Stereo sound will be faint and very distorted if you accidentally leave the Bridging switch
in its Mono position.
Mono Operation
We recommend an 8 ohm minimum speaker load for bridged mono opera-
tion. For mono the Model 2125 “bridges” the R channel to amplify only the
positive half of the audio signal and the L channel to amplify only the nega-
tive half of the audio signal. In effect, each channel “sees” only half of the
speaker’s rated impedance, so that an 8 ohm speaker in bridged mono is
only a 4 ohm load and a 4 ohm speaker in mono is only a 2 ohm load. This
is why the mono power output is much higher than the sum of the L and R
channel outputs for stereo operation.
Mono Input and Speaker Connections
1. Turn the unit off and remove the AC cord.
2. Connect the single cable from the preamp or controller to the R channel Input jack.
3. Set the Bridging switch to its Mono position.
4. Connect the positive lead of the speaker wire to the red R + channel speaker pair A terminal.
5. Connect the negative lead of the speaker wire to the red L + channel speaker pair A terminal.
6. Do not connect anything to either the L - or R - speaker terminals.
7. If you have a second mono speaker repeat steps 4 - 6 with the speaker pair B terminals
8. Reconnect the AC cord.
Note:
The Model 2125 creates more heat when it drives a bridged mono speaker or multiple
speaker pairs. Lower impedance speakers will make it run even hotter. Heat greatly reduces
the life of the amplifier and nearby components. Please heed the instructions for setting the
Load Impedance switch to avoid overheating.
Load Impedance Switch
6
CAUTION
To Prevent Electric Shock, Do Not
Remove Cover. No User-Serviceable
Parts Inside. Refer Servicing To
Qualified Service Personnel.
WARNING
To Prevent Fire Or Shock Hazard,
Do Not Expose This Unit To Rain
Or Moisture.
2125 Two Channel Amplifier
Parasound Products, Inc.
San Francisco, CA U S A
THX and Ultra2 are trademarks of THX Ltd.
which may be registered in some jurisdictions.
All right reserved.
Speaker Pair A
L
R
Mono
Manual
Audio Sens
Max Min
12V Trigger
Ground
Lift Norm
Mono
Stereo
4-8
Ohms
2-3
Ohms
230V
50Hz
115V
60Hz
20Hz 40Hz
Flat
Audio
Auto Turn On
Loop
Level
Bridging
Input
12V
In
Loop
R
Mono
THX
THX
AC 115V/60Hz
AC 230V/50Hz
Power Consumption: 550W
AC
Voltage
Load
Impedance
L
High Pass Filter
Speaker Pair B
L
R
Mono
CAUTION
To Prevent Electric Shock, Do Not
Remove Cover. No User-Serviceable
Parts Inside. Refer Servicing To
Qualified Service Personnel.
WARNING
To Prevent Fire Or Shock Hazard,
Do Not Expose This Unit To Rain
Or Moisture.
2125 Two Channel Amplifier
Parasound Products, Inc.
San Francisco, CA U S A
THX and Ultra2 are trademarks of THX Ltd.
which may be registered in some jurisdictions.
All right reserved.
Speaker Pair A
L
R
Mono
Manual
Audio Sens
Max Min
12V Trigger
Ground
Lift Norm
Mono
Stereo
4-8
Ohms
2-3
Ohms
230V
50Hz
115V
60Hz
20Hz 40Hz
Flat
Audio
Auto Turn On
Loop
Level
Bridging
Input
12V
In
Loop
R
Mono
THX
THX
AC 115V/60Hz
AC 230V/50Hz
Power Consumption: 550W
AC
Voltage
Load
Impedance
L
High Pass Filter
Speaker Pair B
L
R
Mono
