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Standby Amplifier Changeover Unit


8 Duty / 1 Standby Auto Amplifier

Amperes 8 Duty/ 1 Standby Auto Amplifier Changeover- AX3800 MKII

AX3800 MK II is an improved version from its predecessor, offering greater flexibility and simplicity for amplifier fault changeover setup including cascading 2 units for a single standby power amplifier to serve 16 duty units.

With new circuit, amplifier fault detection period is shortened remarkably to initiate faster response for a changeover as well as channel recovery.

Other familiar features are including the priority changeover to avoid overloading, pilot tone generation at intervals to reduce workload of amplifiers and buzzer alert for fault detection. RS485 port is available for remote monitoring at central system.

8 duty / 1 standby, Cascade to enable 16 duty / 1 standby

Priority changeover and overloading protection of standby amplifier

RS485 and dry contact for external monitoring

  • Cater for 8 duty and 1 standby

  • Expandable to 16 duty and 1 standby

  • Built in Pilot Tone, transmit at intervals and senses at sequence to protect amplifiers

  • Overloading protection for standby amplifier

  • Prioritized changeover 

  • Short detection time from 7 seconds

  • Fast recovery time

  • Changeover at inputs and outputs ; suitable for matrix setup

  • Input link switch for easier source connections

  • Channel isolation switch for unused channel

  • LED status monitor

  • Buzzer for fault detection with on/off switch

  • RS485 data port for remote monitoring

  • Fault dry contact 

Technical Specifications

Operating voltage

Power consumption

Standby power

Input signal

Input impedance

Audio output gain

Pilot tone intervals

Pilot tone frequency

Detection line

Detection level

Failure detection

Failure recovery

Zone load rating

Status LED

Changeover alert

Changeover section

Dimensions (WxHxD)


24V DC

2.5W ( 0.11 A )

2.3W ( 0.95 A )

8 Ch balanced line

10 K Ohm


8 seconds / ch

20 kHz ( +/-5% )

70 / 100V rms

5V rms min

20 secs max

20 secs max

500W 100V

Normal, Fault, Changeover

Buzzer with switch

Input and Output

482 X 44 X 180 mm

3.55 kg



Instruction Manual

ACAD Image 

Version 1.00

Updated : Apr 2022

Refer to product brochures for detailed specifications

Front and Rear Views
Amperes 8 Duty/ 1 Standby Auto Amplifier Changeover- AX3800 MKII (Front View)
Amperes 8 Duty/ 1 Standby Auto Amplifier Changeover- AX3800 MKII (Rear View)
Cross References
The predecessor to this version which has been discontinued for a more enhanced version - mk II
8 duty / 1 standby manual changeover unit, which performs standby amplifier changeover via front switch or automatically if used with QP or QD power amplifiers, activation through dry contacts 
Application Schematic
Amperes 8 Duty/ 1 Standby Auto Amplifier Changeover- AX3800 MKII (Application Schematic)
Duty Amplifier 1
Duty Amplifier 8
100V line
Balanced Audio
Standby Amplifier
Speaker Zone Selector
Emergency Paging Panel
Pre-amplifier Mixer
AX3800 MK II
Balanced Audio
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