8
CONTROL INPUT AND OUTPUT
A control (trigger) system is provided on the ST125.3, ST125.2 and ST125.1 amplifiers to allow remote switching
of the amplifier’s standby on/off feature. The control input is designed to operate with a source (trigger) of 5-24
volts AC or DC. All B&K A/V processors and preamplifiers may easily be utilized to control this standby on/off
feature.
In addition your amplifier has a control output circuit to allow control of an external device such as another power
amplifier, projection screen, power strip, etc. The control output has the capability to source 12VDC @ 125 mA
(on) or 0 VDC (off).
If more that one amplifier is being controlled, the control output may be extended to include each successive unit
by simply connecting a 1/8” mini-jack cable from the CTRL OUT connector of the first amplifier to the CTRL IN
connector of next unit (commonly referred to as ‘daisy chaining’). An example of how to connect two amplifiers is
illustrated in the diagram below.
Rear view of second
amplifier with control input
Rear view of amplifier
with control input
Daisy chain to
other amplifiers
From preamplifier
rear panel
control output
C O N T R O L I / O
C T R L
I N
C T R L
O U T
1 2 V D C
1 2 5 m A
+
CONTROL IN ALLOWS AMPLIFIER
OPERATION WHEN A 5-24V SIGNAL
IS APPLIED WITH A 3.5mm MINI JACK
C O N T R O L I / O
C T R L
I N
C T R L
O U T
1 2 V D C
1 2 5 m A
+
CONTROL IN ALLOWS AMPLIFIER
OPERATION WHEN A 5-24V SIGNAL
IS APPLIED WITH A 3.5mm MINI JACK
DO NOT POWER MOTORS WITH THE CONTROL OUT CIRCUIT!!!
If the control function is desired, each unit in the system must remain connected at all times and the control must
be enabled. To enable the control function, the CTRL IN jack must have a 3.5mm mini-jack inserted for each
controllable amplifier in the system. For more information on the amplifier’s output status under various control
conditions, refer to the table below.
*
Note: The control input voltage is intended for
standby on/off
control only. For proper amplifier operation, it is
recommended that each amplifier have its own source of AC power.
@ CTRL IN
Button Position
Output Status
@CTRL OUT
Signal OUT Sound Signal
Signal IN
Sound Signal
No Signal
OUT
Mute/Standby
No Signal
No Signal
IN
Sound
Signal
