Samson 170 - Manual (Page 15)

Appendix E: Bridged Mono Mode (Servo-550 Only)
The Servo-550 amplifier provides a rear-panel switch that allows it to be used in
a bridged mono mode. When this switch is placed in the “Stereo” (up) position,
the Servo-550 functions as a true stereo amplifier, where both of the two
independent amplifier channels (left and right) can receive different input signal
and produce independent output signal. However, when the switch is placed in
the “Bridged Mono” (down) position, both amplifier channels process only the
signal present at the left input, thus producing a monophonic output signal with a
true 550 watt output (into 8 ohms).
The illustration on the left shows how this works. In bridged mono mode, the
polarity (phase) of the right output signal is reversed relative to that of the left
output signal. Both channels then process the same signal, with the speaker
load 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-550 in bridged mono mode, be sure to connect the
loudspeaker as shown in the illustration below, with the hot (+) terminal of the left
channel connected to the positive input of the speaker and the hot (+) terminal of
the right channel connected to the negative input of the speaker. Do not use
the ground output terminal of either channel (the speaker load must “float”
away from the amplifier chassis).
15
BRIDGED
MONO
STEREO
SAMSON
TO PREVENT SHOCK DO NOT OPEN. NO USER
SERVICABLE PARTS INSIDE. REFER SERVICING
T O Q U A L I F I E D S E R V I C E P E R S O N N E L . T O
PREVENT FIRE OR SHOCK HAZARD DO NOT
EXPOSE TO RAIN OR MOISTURE.
CAUTION
HEATSINK MAY BE HOT!
DO NOT BLOCK AIRFLOW
OR OVER-HEATING MAY
OCCUR
RISK OF ELECTRIC SHOCK
DO NOT OPEN
S/N FU SE
FUSE
10A/250V
CAUTION
!
~AC INPUT
115V/60Hz,1080W
USE CLASS 2 WIRING MAXIMUM LOAD IMPEDANCE 4 Ω
RIGHT LEFT
OUTPUT 275W/4 Ω
SERVO 550 STUDIO AMPLIFIER
RIGHT
LEFT
INPUTS
(BALANCED
10K Ω /0dBu)
TIP RING SLEEVE
TIP +
RING -
SLEEVE GND
BRIDGED
MONO
STEREO
BRIDGED MONO 8 Ω - +
GROUND +RIGHT LEFT + GROUND
CAUTION; REPLACE
WITH THE SAME TYPE
FUSE AS INDICATED.
UTILISER UN FUSIBLE
DE RECHANGE DE
MEME TYPE.
+
-
WARNING: Bridged mono mode is to be used only when the Servo-550 is
connected to an 8 ohm speaker load. Use of bridged mono mode with
speaker loads of 4 ohms or less can result in severe damage to the unit
due to excessive heat and current limiting and will void your warranty!
Never use bridged mono mode during stereo operation. If loudspeakers
are connected to both channel outputs of the Servo-550 when used in
bridged mono mode, they will be severely out of phase with one
another (there will be an extreme loss of low end).
INPUT
LEFT(+)
OUTPUT
RIGHT(+)
OUTPUT