Biema A4157 Amplifier Apple Series Owner’s Manual

Biema A4157 Amplifier Apple Series

BIEMA AMPLIFIER APPLE SERIES PROFESSIONAL FORCE AMPLIFIER

TECHNICAL DATA & INTRODUCTION

/un-Balanced
Signal/noise ratio a-weighted RMS| :;,s5dB
Crosstalk at rated output power 8 ohm 1kHz| >70dB
Damping fader I= 1kHz 8 ohms| >240
Slew rate internal| 15V/uS
Protection| SHORT CIRCUIT, CURRENT LIMITED DC FAULT AC LINE FUSE,

THERMAL CUT OFF, POWER UP/DOWN TRANSIENTS

Indicators| POWER REEN)PROT(RED)CLIP(YELLOW) SIG (GREEN)
Cooling| VARIABLE SPEED FAN
Front panel controls| LEVELACH, BCH POWER SWITCH
Rear panel controls| STEREO/BRIDGE/PARALLEL MODE SWITCH
Connector| XLR BALANCED INPUT, PROFESSIONAL SPEAKON OUTPlJT,
Power consumption half power 8 ohms| <720:
Power supply| $&  9  +]
Dimensions(WX DX H)mm Interior/Exterior| 483x320x88/( 575[425[150  )mm
N.W/G.W|   NJ  NJ

PROFESSIONAL FORCE AMPLIFIER

The information furnished in this manual does not include all of the details of design, production, or variations of the equipment, Not does it cover every possible situation that may arise during installation, operation or maintenance. If you need special assistance beyond the scope of this manual, please contact our Technical Support Group.

MAGNETIC FIELD
CALITION
DO not located sensitive high-gain equipment such os preamplifier or topaz decks diracllr above or below The unit. Because this amplifier has a high power densely, it has a strong magnetic field, which MN induce hum into unshielded devices lulls are lottiid nearby. The field is strongest just above and below the unit. If an equipment rack is used, we recommend locating the amplifier(s) in The bottom of the rock and The preamplifier or lather sensitive equipment  the top.

WATCH FOR THESE SYMBOLS

The lightning bah triangle A The exclamation point triangle is used for Electric clock.

INTRODUCTION

BIEMA APPLE series amplifier represents a major step forward in Biema power amplifier technology and design. In 1987 Mr. Biema collaborated with professors at Electro acoustics Research Center of Princeton University and established Biema Acoustics R&D Center. Under his passion at music, Mr. Biema has contributed most of his time and technology at the development of Biema audio equipments. Biema professional amplifiers are coming with excellent sound effect but with very reasonable price. It offers quality guarantee and technological support for the apparatus you are using.

Quiet Operation
High quality of the power transformers reduces external magnetic field radiation, which can induce audible hum into associated equipment and cabling. In addition, the up-to-dated technology components are incorporated throughout the design to ensure extremely low noise generation Biema all fore Series power amplifiers.

DC Voltage protection
If an amplifier channel detects DC voltage at output terminals, the output relay will immediately open to prevent loudspeaker damage. The protection LED will light.

Reliable Power Supply
The Biema APPLE Series amplifiers have automatic power supply protection. The power supply has experienced DC automatic regulation, which grants Biema APPLE Series amplifiers excessive reliability. Biema APPLE amplifiers can be wired for 115/230v 50Hz-60Hz AC power supply.

GENERAL
Biema’s new APPLE series amplifiers are high performance and high efficiency’s top quality amplifiers. To get good effecting of cooling and highest work efficiency, variable speed fan and T type heat-sink have adopted for constant cooling. Besides, APPLE series amplifiers have their comprehensive protect function.

1. Power ON/OFF transient, prevents the surge assault.
2. Thermal cut off protection, the amplifier will cut off the link with speakers when the temperature is more than IOO”C.
3.  Short circuit current limited protection.
4. The muting circuit prevents switching noise by turning the amplifier on or off.
5. DC protection at speaker output, the amplifier will cut off the link with speakers when the amplifier is unusual.
6. Limitor protection, providing voltage of compression without distortion, the amplifier will not clip.

PRECAUTIONS

1. Don’t stack anything upon the amplifier.
2.  Always use a power source of adequate capacity.
3. DO NOT turn ON/OFF the power of continuously. Never allow the ventilation holes on the front of the amplifier to be obstructed in any way.
4. Input level adjust controls are provided on each channel.
5.  Output can use binding posts, speak on posts.
6. When the amplifier works in stereo, bridge-mono or parallel-mono mode, the switch must be on the same.
7. Fan’s variable speed may produce light noise, which is normal when continuous output large power and amplifier gives out heat.
8. To clean the amplifiers, wipe it wipe a dry cloth, if the case is very dirty, disconnect the AC cord form the power source and wipe it with a dry cloth. Never use solvents or chemical cloth. Never spray insecticides as they may cause discoloration or peeling.
9. If any trouble is found, disconnect the power and contract your distributor.

MAJOR OPERATING CONTROLS AND THEIR FUNCTIONS

FRONT PANEL

1. MAINS POWER SWITCH
   When press the switch, the soft start circuit run for avoiding surge strike. In about 3-4 seconds, there will be a clicking denote that soft start finished. And more 1-2 seconds later, there will be another “Clicking”, the amplifier is connected with speaker and ready to work.

2. CH-1/CH-2 INPUT LEVEL CONTROL
   Adjust it to get the volume desired.

3. CH-1/CH-2 PROTECTION INDICATING LED
   These LEDs will light up when the amplifier is running un-stable or went in to thermal protection after the power elements temperature over 90 ·c.

4. CH-1/CH-2 CLIP INDICATING LED
   Turns on just before the maximum, distortion free, output level of the amplifier. The clip LEDs may turn on shortly from time to time but they may certainly not turn on for longer periods. In this case you have to turn the output level down.

5. CH-1/CH-2 Signal Presence LED
   Green LED ,one perehannel, Dashes when input signal exceeds -80dBu.

6. CH-1/CH-2 POWER LED
   Green LED,LED illuminates green when amplifier is on.

REARPANEL

1. CH-1/CH-2 input XLR
   standard XLR jack, below is the connection method; Pinl: signal ground, Pin2: signal+, Pin3: signal-

2. CH-1/CH-2 Signal Link Output
   Standard XLR (male) socket for input signal link, its Pins parallel connected with the female XLR socket so you can feed the same signal to another amplifier. Pinl: signal ground, Pin2: signal+, Pin3: signal-
   

3. Output Mode Set Switch.
   Select the run mode as STEREO or BRIDGE or PARALLEL

4. CHl/CH-2 SPEAKON
   post output Used by a standard SPEAKON connector.

5. CH1/CH-2Binding_post
   output Used by a standard Binding post connector.

6. Mains Power Supply Cord
   

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