Bridge Stereo Mode
The Servo Quad Amplifier provides two rear-panel switches that allow it to be
used in a unique bridge stereo mode. When these switches are in their “Off”
(left) position, the Servo Quad Amplifier functions as a true quad amplifier, where
each of the four independent amplifier channels can receive different input signal
and produce independent output signal. However, when either switch is placed
in the “On” (right) position, the pair of amplifier channels (1/2 or 3/4) process only
the signal present at one input, thus producing a monophonic output signal with
a true 120 watt (in the case of the Servo Quad 4060 model) or 240 watt (in the
case of the Servo Quad 4120 model) output into 8 ohms. When both Bridge
switches are placed in the “On” position, the Servo Quad amplifier operates in
bridge stereo mode, acting like a true stereo amplifier, delivering 120 watts of
power per channel (in the case of the Servo Quad 4060 model) or 240 watts of
power per channel (in the case of the Servo Quad 4120 model).
The illustration on the left shows how this works. In bridge stereo mode, the
polarity (phase) of the channel 1 output signal is reversed relative to that of the
channel 2 output signal (similarly, the channel 4 output signal is reversed relative
to that of channel 3). Channels 1 and 2 then process the signal being input to
channel 2 (and channels 3 and 4 process the signal being input to channel 3),
but the speaker load is connected so that power is derived from both channels.
The effective voltage swing seen by the load is thus doubled so that the power
output is doubled.
When using the Servo Quad Amplifier in bridge stereo mode, be sure to connect
each loudspeaker as shown in the illustration below (and as silkscreened on the
rear panel), with the red (+) terminal of channel 2 (and/or channel 3) connected
to the positive input of the speaker and the red (+) terminal of channel 1
(and/or channel 4) connected to the negative input of the speaker.
Do not use the black (-) output terminal of either channel (the speaker load
must “float” away from the amplifier chassis).
9
BRIDGE
OFF
ON
+
-
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
!
USE CLASS 2 WIRING
AVIS;
RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
DO NOT EXPOSE THIS EQUIPMENT
TO RAIN OR MOISTURE.
emc
EUR . USA . JPN
BRIDGE
OFF
ON
CH4 R
CH3 R
-
+
+
-
CH2 L
CH1 L
-
+
+
-
BRIDGE
OFF
ON
SAMSON
SERIAL NUMBER
SERVO 4120
QUAD AMPLIFIER
SAMSON TECHNOLOGIES CORP., U.S.A.
AC
INLET
USA & CANADA 115V - 60Hz
EUROPE & UK 230V - 50Hz
650W MAX.
CAUTION:
DISCONNECT SUPPLY CORD
BEFORE CHANGING FUSE.
FOR CONTINUED PROTECTION
AGAINST RISK OF FIRE, REPLACE
ONLY WITH SAME TYPE OF FUSE.
ATTENTION:
DEBRANCHER AVANT DE
REMPLACER LE FUSIBLE.
UTILISERUN FUSIBLE DE
RECHANGE DE MEM TYPE.
USA & CANADA
T 8A/125V (115V)
EUROPE AND UK
T 6.3A/250V (230V)
FUSE
CH4
CH3
4
Ω
120W
MAX. LOAD
-
+
+
-
MONO 8
Ω
-
+
CH2
CH1
4
Ω
120W
MAX. LOAD
-
+
+
-
MONO 8
Ω
-
+
WARNING: Bridge stereo mode is to be used only when the
Servo Quad Amplifier is connected to an 8 ohm speaker load.
Use of bridge stereo mode with speaker loads of 4 ohms or less can result
in severe damage to the Servo Quad Amplifier due to excessive heat and
current limiting and will void your warranty!
INPUT
(CHANNEL 2)
CHANNEL 2
(+) OUTPUT
CHANNEL 1
(+) OUTPUT
