OPERATING INSTRUCTIONS DUAL POWER AMPLIFIERS DA-250D CU DA-250DH CU Note: The figure shows the DA-250D. Thank you for purchasing TOA's Dual Power Amplifier. Please carefully follow the instructions in this manual to ensure long, trouble-free use of your equipment.
TABLE OF CONTENTS 1. IMPORTANT SAFETY INSTRUCTIONS .................................................... 3 2. SAFETY PRECAUTIONS ............................................................................... 4 3. GENERAL DESCRIPTION ............................................................................. 6 4. FEATURES .......................................................................................................... 6 5. HANDLING PRECAUTIONS ......................................................
1. IMPORTANT SAFETY INSTRUCTIONS • Read these instructions. • Keep these instructions. • Heed all warnings. • Follow all instructions. • Do not use this apparatus near water. • Clean only with dry cloth. • Do not block any ventilation openings. Install in accordance with the manufacturer's instructions. • Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
2. SAFETY PRECAUTIONS • Before installation or use, be sure to carefully read all the instructions in this section for correct and safe operation. • Be sure to follow all the precautionary instructions in this section, which contain important warnings and/or cautions regarding safety. • After reading, keep this manual handy for future reference.
• When moving the unit, be sure to remove its power supply cord from the wall outlet. Moving the unit with the power cord connected to the outlet may cause damage to the power cord, resulting in fire or electric shock. When removing the power cord, be sure to hold its plug to pull. • Avoid installing the unit in humid or dusty locations, in locations exposed to the direct sunlight, near the heaters, or in locations generating sooty smoke or steam as doing otherwise may result in fire or electric shock.
3. GENERAL DESCRIPTION TOA's DA-250D and DA-250DH Dual Power Amplifiers feature high power handling capabilities and durability. The DA-250D is configured with 250 W x 2 channels (4 Ω output) and 170 W x 2 channels (8 Ω output), and the DA-250DH features a 250 W x 2 channels (19.6 Ω output) configuration. Besides, each model's output is made available for bridge connection, allowing it to be used as a monaural amplifier of 500 W (8 Ω for DA-250D, 39.2 Ω for DA-250DH).
6. INSTALLATION PRECAUTIONS CAUTION Rack mounting screws are not supplied with the unit. Be sure to use the screws with a diameter of over 5 mm (0.2") and length of over 12 mm (0.47") to mount the unit. Failure to do so may cause personal injury. • The supplied power supply cord is designed for exclusive use with this unit. Never use it with other equipment. • When mounting the unit in an equipment rack, the inside of the rack must be sufficiently ventilated.
7. NOMENCLATURE AND FUNCTIONS [Front] 3 4 5 2 1 Note: The figure shows the DA-250D. 1. Power switch [ ON / OFF] Power is switched on and off with each depression of this switch. 2. Power indicator [POWER] Lights blue when the power is switched on. 3. Input level controls [CH 1/BRIDGE, CH 2] Adjust the input level of each channel.
[Rear] 6 7 8 9 10 DA-250D 11 DA-250DH 6 7 8 9 10 11 6. AC inlet Connect the supplied power cord to this inlet. 7. Functional ground terminal [SIGNAL GND] Hum noise may be generated when external equipment is connected to the unit. Connecting this terminal to the functional ground terminal of the external equipment may reduce the hum noise. Note This terminal is not for protective ground. 8. Speaker output terminals (with a terminal cover) Connect speaker cables to these terminals. 9.
8. SETTINGS AND CONNECTIONS BRIDGE ON/OFF switch CH 1 mode ON/OFF switch [Rear panel] Speaker output terminals (with a terminal cover) Input terminals Note: The figure shows the DA-250D. Step 1. Switch off the unit's power. Step 2. Set the BRIDGE ON/OFF switch and CH 1 mode ON/OFF switch. Step 3. Connect the sound source equipment to the Input terminals. Note: Refer to p. 12 for the removable terminal plug connection. Step 4. Connect speakers to the Speaker output terminals. 4-1.
8.1. Switch Settings and Speaker Connections [2 inputs - 2 outputs] (factory-preset) Speaker output terminals CH1 CH1 CH2 Switch Setting BRIDGE OFF CH 1 mode OFF CH2 CH1 CH2 DA-250D DA-250DH 4–8Ω 19.6 Ω 4–8Ω 19.6 Ω DA-250D DA-250DH 4–8Ω 19.6 Ω 4–8Ω 19.6 Ω DA-250D DA-250DH 8Ω 39.
9. REMOVABLE TERMINAL PLUG CONNECTION Cautions • Be sure to use shielded cables for audio signal lines. • Avoid soldering cable conductor, as contact resistance may increase when the cable is tightened and the solder is crushed, possibly resulting in an excessive rise in joint temperatures. • Use cables of AWG 12 – 24. Cable end treatment 7 mm Shielded cable (0.28”) 20 mm (0.79”) Connector connections Step 1. Loosen the terminal screw, then insert the cable. Step 2. Retighten the terminal screw.
10. INPUT SENSITIVITY AND HIGH-PASS FILTER ON/OFF SETTINGS The Input sensitivity can be set to +4 dB (factory-preset) or -10 dB for each channel. Besides, only the DA-250DH employs the High-pass filter on each channel, which can be set to "ON" or "OFF." CAUTION These servicing instructions are for use by qualified personnel only. To avoid electric shock, do not perform any servicing other than that contained in the operating instructions unless you are qualified to do so.
11. PROTECTION OPERATION LIST Failure Protection Operation Indicator Remedy Overcurrent due to overload Current limiter activated when impedance drops below the specified value. Short circuit Current limiter activated. Protection indicator Load is disconnected. lights. Check speakers and lines for short circuit. Turn off the power switch. Correct the load, then switch on the power. Rise in heat sink temperature (over 100°C) Load disconnected. Protection indicator lights.
13. CLEANING THE FILTER Step 1. Switch off the unit's power. Step 2. Remove the ventilation panel as shown in the figure. Step 3. Detach the filter inside the ventilation panel. Step 4. Clear the filter of dust. Step 5. Replace the filter and ventilation panel. Ventilation Panel 2 Filter 3 Detach the panel by pressing on the left or right side.
14. BLOCK DIAGRAMS 14.1. DA-250D CH 1 OUTPUT CH 1 INPUT OUTPUT 1 relay H C E + Current Limiter CH 1 input level control CH 2 INPUT H C E +4 dB Short Detector -10 dB Protection Circuit CH 1 sensitivity selection jumper (+4 dB/-10 dB) BRIDGE OUTPUT OUTPUT 2 relay ON + PARALLEL switch +4 dB CH 2 input level control Current Limiter OFF BRIDGE ON/OFF switch CH 2 OUTPUT Short Detector Protection Circuit -10 dB CH 2 sensitivity selection jumper (+4 dB/-10 dB) 14.2.
15. DIMENSIONAL DIAGRAM (0.89) (1.73) (1.25) 44 31.8 371 (14.61) 442 (17.4) 401.8 (15.82) 22.5 Unit: mm (inches) 465 (18.31) 482 (18.
16. SPECIFICATIONS 16.1. DA-250D CU Power Source Amplification system Power Consumption Input Rated Output Frequency Response Total Harmonic Distortion Protection Circuit S/N Ratio Crosstalk LED Indicator Cooling Operating Temperature Operating Humidity Finish Dimensions Weight 120 V AC, 50/60 Hz Digital class D 120 W (based on UL/CSA standards) 650 W (rated output 4 Ω x 2) 420 W (rated output 8 Ω x 2) 2 circuits, +4 dB* (1.
16.2. DA-250DH CU Power Source Amplification system Power Consumption Input Rated Output Frequency Response Total Harmonic Distortion Protection Circuit S/N Ratio Crosstalk LED Indicator Cooling Operating Temperature Operating Humidity Finish Dimensions Weight 120 V AC, 50/60 Hz Digital class D 120 W (based on UL/CSA standards) 580 W (rated output 19.6 Ω x 2) 2 circuits, +4 dB* (1.
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