DUKANE 1B3250 250 Watt Audio Amplifier Instruction Manual

DUKANE 1B3250 250 Watt Audio Amplifier Instruction

Installation Manual

Model
183250

250-Watt Power Amplifier

General Description

The IB3250 250-Watt Amplifier operates from 120Vac, or from 24Vdc if there is an AC power failure. When AC power is applied to the amplifier, the red power on the front panel illuminates. The primary AC circuit is protected by a 5.25-ampere slow-blow fuse. The inverter power is supplied through a 25-ampere fuse. When the amplifier operates from 24Vdc, the power IED flashes. If the output transistors overheat, the temperature-controlled thermoslat on the heat sink opens the primary circuit and illuminates the thermal overload lED on the front panel. When the temperature is reduced, the thermostat closes the AC power circuit and the IED goes out. For service information on the IB3250, see document number 427-05-00003, latest revision.

Installation Notes

The amplifier provides full rated output with 1 volt input, single-ended.
Connect the rack or console metalware to conduit and electrical system ground. Then place an outside-toothed lockwasher under the head of a mounting screw to ground the amplifier chassis to the rack or console metalware. When removing the amplifier from the rack, DO NOT remove the four chassis mounting screws (Figure 1).In fire alarm/life safety installations, you must use non-power limited fire protective signaling circuit cable for amplifier output connections (25V and 70V levels) to comply with NFPA 72. Use Dukane Cable 176-569 or equivalent For all other installations, Class II wiring can be used. AC power wiring must be Class I wiring only. If the 1B3250 is rack-mounted, there must be ventilation panels above and below the amplifier (see Figure 1 on the previous page). As with any electronic equipment, the useful life will be extended by minimizing the amplifier’s operating temperature. Fill any JeflOverrack space with ventilated panels. Order two ,’.i:60-1232 1-3/4″ (4.4 cm) panels or two 560-1234 3-1/2″ (8.9 cm) panels. Do not fill any rack to more than 2/3 of its capacity with amplifiers. See the associated equipment listed

Battery Connections

The red and black power lock conneclOr is accessible from the rear panel. Mate this connector to the red and black power lock conneclOr terminated IO the 6 foot (1.63 m) battery leads provided with the amplifier. Connect the red wire to positive and the black IO negative at the 24-28Vdc battery backup source. See Figure 2.

CAUTION
Before powering up the amplifier from 24Vdc, verify that the red wire goes lo positive and the black lo negative. Reversal of the leads will result in failure and void the warranty.

CAUTION
Wiring outside the equipment rack must be Class I.

The DC power required for the amplifier is 1.6 amps at idle, 22 amps at rated output.
If the amplifier(s) and battery are IO be ten or more feet apart, add extra wire IO the provided red and black wire by a barrier block or similar means. See the table on the next page for the appropriate wire gauge.

 | Feet|
---|---|---
Amplifiers| 10| 20| 30| 40| 50| 60| 70| 80| 90| 100
1 (25 adc)| 12| 10| 8| 6| 6| 4| 4| 4| 3| 3| __

:;;::i::i

. – , ·  0 µ:

n, 8

==   !3

=

•   Q.

Q n , ,.

2 (50 adc)| 8| 6| 4| 4| 3| 2| 1| 1| 0| 0
3 (75 adc)| 6| 4| 3| 2| 1| 1| 0| 2/0 ·| 2/0| 3/0
4 (100 adc)| 3| 3| 2| 1| 0| 2/0| 3/0| 3/0| 4/0| 4/0
S (125 rule)| 2| 2| I| 0| 2/0| 3/0| 4/0| 4/0| –| –
6 (150 adc)| 1| 1| 0| 2/0| 3/0| 4/0| 4/0| –| –| –
7 (175 adc)| 2/0| 2/0| 2/0| 2/0| 4/0| 4/0| –| –| –| –

*These recommendations are in compliance with NEC standards.
Wiring Chart for Battery Connection

External Connections

Make all external connections to the screw terminals on the rear of the amplifier. Do not connect AC power to the amplifier until all external connections have been made and have been found to be free of short circuits. A conventional speaker system of up to 250 walls, including appropriate speaker- loIine matching transformers, can be connected to this amplifier.

Input Level

No more than 1 volt rms (sine wave) input is required to obtain full output power.  However, it is recommended that the input be lowered 8dB in order to accommodate the complex wave form of program material. Connect a vollrneter to the 25-volt or 70-volt amplifier output. Tum the input level control (R.101) counterclockwise to OFF. Apply 700Hz to lkHz sine wave at 1 volt at the amplifier input. Adjust the input level control for a reading of 10 volts on the 25-volt output or 25 volts on the 70-volt output

Input Connections

Make the input connections to the IN and COM screw tenninals with shield to COM as shown in Figure 3. The link provides a connection from the internal circuit common bus to the chassis common. Unless some unusual installation requires that the chassis not be audio ground, LEA VE THE JUMPER LINK IN PLACE.

Bridging Connections

The bridging input {BRDG) is used when one signal source will serve as the input source for multiple amplifiers (Figure 4). The BRDG input mixes with the nonnal signal input applied to IN. The bridging input is primarily used for life safety systems that use a 27Hz generator to supervise multiple amplifiers. If the bridging input is used to feed multiple amplifiers with a common broad band program source (such as a tuner source) remove capacitor Cl 1 (0.00lmF) from the 110-3303 driver board. To reduce the crosstalk of nonnal audio inputs between amplifiers connected together with common bridging inputs, keep the bridging resistor as large as possible.

Output Connections

Connect the speaker lines as shown below. In frre alann/life safely inslallations, nonpower limited fire protective signaling circuit cable must be used for amplifier output connections (25V aud 70V levels) to comply with NFPA 72. Use Dukane Cable 176- 569 or equivalent. For all other inslallations, Class II wiring cau be used.
When this amplifier is used in sound systems with 25-volt intercom operation, connect the 25V CT (center tap) to the sound system ground to minimize crosstalk

CAUTION
Under no circumstances should the outputs of muHiple cmplifiers be connected together lo feed a single speaker circuit. Amplifier damage may result .

The Dukane Model 600-8027 Metal Oxide Varistor (MOY) Assembly is a transient voltage suppressor for use across power amplifier speaker output terminals. This MOV is required only on UL approved life safely systems, but is also recommended for other systems if the potential for lightning damage exists. See the MOV Assembly’s inslallation sheet (402-441, latest revision) for instructions.

AC Power Connections

IMPORTANT:
Before connecting AC power to this amplifier, MAKE SURE the output load is correct (i.e. that the speakers are correctly matched to the speaker line) and the input connections are properly made to the amplifier terminals.
AC power wiring MUST BE CLASS I WIRING ONLY.

Reducing Battery Current ConsumptionWhen Amplifier is Idle
The amplifier consumes 1.6 amps DC when the amplifier is operating from 24Vdc with no speech input This is the idle condition. If the amplifier is not actively in use while on battery power, you can reduce battery current consumption to 0.06 amp by placing the inverter in the standby condition. This is done by connecting an N.C. contact between taper pins B (or SHlITOOWN) and A (or MODE STATUS) on the 110-3304 250-Watt Inverter Circuit Board (Figure 6). When the amplifier is required to operate while on battery backup, opening the connection from B to A will power up the amplifier.

The switch used to control the battery mode shutdown function is typically provided by contacls in a microphone, tone generator, tape deck, or other audio control port.
Note:
The amplifier will NOT operate in the battery mode with the SHUTDOWN and MODE ST A TUS pins shorted together. To restore battery operation, this connection must be broken.

Battery Discharge Curves at Various Currents
You can estimate the number of hours the standby battery will operate at various levels (e.g., full power, half power) by looking at Fignre 7. The CDF Series Globe Gel/Cell Charger, or equal, is recommended for charging the standby battery. Contact the Johnson Controls Globe Battery Division for battery information.

Associated Equipment

• The Model 3AI30 Input Transformer isolates equipment and eliminates ground problems.
• The Model 3A230 Input Transformer permits you to run multiple amplifiers from a single 600 ohm mixer output and have all the benefits of isolation.
• The Model 110-1188 Input Transformer Adapter is a transformer mounting bracket with a 3-contact terminal strip, an octal socket for receiving a plug-in input transformer, and a hole for an input level potentiometer shaft See the associated installation instructions in document number 402-236, latest revision.
• The 560-1232 is a 1-3/4″ (4.4 cm) ventilated panel.
• The 560-1234 is a 3-1{}.” (8.9 cm) ventilated panel.
• The Model 2A95 Line Amplifier is used if the input voltage to the amplifier is less than 1 volt

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References

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