Biema A 4173A User manual
Operating Instructions
A 4173A
PA Amplifier Stereo/Bridgeable 2x550W
This PA Amplier is an effective solution for demanding commercial audio
applications. This new series dubbed the “Apple” range have been com-
pletely redesigned by Biema to offer vastly improved cooling, efciency
and circuit protection. This range is designed to function as a stereo or high
power single channel amplier for use in foreground sound reinforcement
ie: pubs, clubs, cinemas and multi-function venues. The variable speed cool-
ing fan and ‘T’ shaped heatsink tunnel ensure the amplier
performs well even in demanding conditions.
A 4173A
PA Amplifier Stereo/Bridgeable 2x550W
Front Panel
1. Mains Switch
When you rst press the switch, a soft start circuit will run to avoid a surge
strike. In about 3-4 seconds there will be a click to indicate that the soft start
has nished. 1-2 seconds later there will be another click to indicate the
amplier is connected.
2. CH-1/CH-2 Input level control
Adjust the control to the desired volume. Only use the CH-1 control whilst
amplier is set in Bridge or Parallel mode.
3. CH-1/CH-2 Protection indicating LED
The LED will light up red to indicate when the amplier is running un-stable
or has gone into thermal protection.
4. Clip LED
This LED turns on just before the maximum output level of the amplier
has been reached. The clip LED’s may also turn on from time to time due to
song selection however they shouldn’t stay lit for long periods of time. When
this occurs we suggest you turn the output level down.
5. Bridge mode indicating LED
When this LED lights, it indicates the amplier is working under BRIDGE
mode. The input signal only acts on CH-1.
6. Parallel mode Indicating LED
When this LED lights, it indicates that the amplier is working under
PARALLEL mode. The input signal only acts on CH-1.
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A 4173A
PA Amplifier Stereo/Bridgeable 2x550W
Rear Panel
1. CH-A/CH-B input XLR
Standard XLR jack, below is the input method
Pin1: signal ground, Pin2: signal+, Pin3: signal-
2. CH-A/CH-B Signal Link Output
Standard XLR (male) socket for input signal link, its Pins are parallel
connected with the female XLR socket so you can feed the same signal to
another amplier. Pin1: signal ground, Pin2: signal+, Pin3: signal-
3. CH-A/CH-B Output Mode Set Switch
Select the run mode as STEREO, BRIDGE or PARALLEL
4. CH-A/CH-B Output SPEAKON
Standard speakon socket 1+2+: 1-2-:
5. Mains Power Supply Cord
• Rugged heavy duty construction
• 19” rack mount
• Bridgeable, parallel or two channel stereo operation
• Earth lift switch
• 3 pin XLR and 6.35mm inputs.
• Short circuit protection with indicator
• Overload protection with indicator
• Clipping prevention circuitry with indicator
• Variable speed fan forced cooling
• Muting circuit for switch on/off
Features
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A 4173A
PA Amplifier Stereo/Bridgeable 2x550W
Specications
Power: 2 x 550W 8Ω, 2 x 800W 4Ω
Power (bridged): 1600W 8Ω
Output Connections: SPEAKON
Freq. response: 20Hz - 20kHz ±0.5dB
Input sensitivity: 0.77V
Input Impedance: 20k Ω/Balanced, 10k Ω/un-balanced
S/N Ratio: ≥95dB
THD: ≤0.03%
Crosstalk @ Rated Output/8kΩ/1kHz: >70dB
Damping Factor/8kΩ/1kHz: >240
Slew Rate: 15V/uS
Protection: Soft Start, Short Circuit, Limiter, DC Fault,
AC Line Fuse, Thermal Cut
Cooling System: Two Steps speed fan
Mains Power Supply: AC: 220-230V 50Hz/60Hz
Dimensions (mm): ≈ 482W x 430D x 88H
Net Weight: 10.5kg
Gross Weight: 12.5kg
Safety Instructions
Caution: To reduce the risk of electric shock, do not remove any parts.
No user serviceable parts inside. Refer servicing to qualied service
personnel only.
WARNING: To reduce re or electric shock do not expose this appli-
ance to rain and moisture. Electrical equipment should never be kept
or stored in damp environments.
1. Read instructions before the product is connected and used.
2. Retain Instructions for future reference
3. Follow the warnings in instructions
4. Do not expose this appliance to heat sources such as radiators
5. The appliance should be placed so nothing interferes with its ventilation.
6. This appliance should be connected to a power supply thats suitable. Be sure
to connect the appliance to a mains power socket which features a protective
grounding connection.
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