Biema A 4155 User manual

Operating Instructions
A 4155
PA Amplifier Stereo 2x150W
This PA Amplier is an effective solution for demanding commercial audio
applications. This new series dubbed the “Apple” range have been
completely redesigned by Biema to offer vastly improved cooling, efciency
and circuit protection. This range is designed to function as a stereo or high
power single channel amplier for use in foreground sound reinforcement
ie: pubs, clubs, cinemas and multi-function venues. The variable speed
cooling fan and ‘T’ shaped heatsink tunnel ensure the amplier
performs well even in demanding conditions.

A 4155 PA Amplifier Stereo 2x150W
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
amplier is connected.
2. CH-A/CH-B Input level control
Adjust the control to the desired volume. Only use the CH-A control whilst
amplier is set in Bridge or Parallel mode.
3. CH-A/CH-B Clip Value Indicator
The LED will light up red to indicate when the output signal has reached its
clipping level. If this occurs adjust the input level controls so the LED turns
off. When the audio signal is being recieved at the input the LED lights
continuously. If no sound comes from the speaker its possible that there is a
short circuit in the speaker line. Turn off the amplifer, detect where the fault
is occuring and remedy the fault.
4. CH-A/CH-B Protection Indicator
The LED will light up yellow to indicate the following; the power transistor’s
temperature is over 100°C, there is an issue or fault with the amplier and
when you have turned amplier on after its been off for 4-6 minutes.
5. CH-A/CH-B Signal
The LED will light up green to indicate when there is a signal input for
channels A and B.
6. Power On Indicator Lamp
The LED will light up blue to indicate the amplier is turned on.
12 2
66
5 5
4 3 3 4

A 4155 PA Amplifier Stereo 2x150W
Rear Panel
1. Mains Power Connector (with fuse socket)
2. CH-A/CH-B Output Connector
Use Banana plugs or bare wire for the speaker connection
through binding posts
3. Ground/Lift Switch
4. CH-A/CH-B Input Connector
Use a 6.35mm connector or 3 Pin XLR connector.
5. Air Vents
When the amplier is on the heat will exit through the air vents so
please use amplier in an area with ventilation
6. Speakon Output Sockets
When the amplier is in stereo mode, you can use the speakon
socket for connection. The standard connection is 1+2+: 1-2-
• Rugged heavy duty construction
• 19” rack mount
• 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
5
1
5
2 664 3

A 4155 PA Amplifier Stereo 2x150W
Specications
Output Power 8Ω: 2x150W RMS
Output Power 4Ω;: 2x220W RMS
Frequency Response: 10Hz - 50KHz -1.5db
Imput Sensitivity: 1V
Signal to Noise Ration: >90dB
Crosstalk at rated power 8Ω 1kHz: >70dB
Damping factor f=1kHz 8Ω: >150
Slew rate internal: 30VµS
Protection: Short circuit, DC fault AC line fuses, Thermal cutoff
Indicators: Power (blue), Clip (red), Protection (yellow)
Cooling: Variable speed fan
Front panel controls: Level (Channel A, Channel B), Power switch
Rear panel controls: Ground/lift switch
Connectors: 6.35mm input, XLR input, Speakon output, Binding post output
Power supply: AC115/230V 50-60Hz
Dimensions(WxDxH): 482x314x88mm
Weight: 11kg
Safety Instructions
Caution: To reduce the risk of electric shock, do not remove any parts.
No user serviceable parts inside. Refer servicing to qualied service
personnel only.
WARNING: To reduce re or electric shock do not expose this
appliance 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.