Toa DA-250D, DA-250DH Specifications

DA-250D/250DH

Dual-Channel Digital Power Amplifiers

DA-250D

DA-250DH

DESCRIPTION

The TOA DA-250D and DA-250DH dual-channel power amplifiers offer a wider choice of power ratings, advanced Class D
amplification circuitry, and a highly efficient AC mains to output power ratio, for the complete technological superiority it takes
to support long-term installation applications. These energy-efficient, space-saving amplifiers are designed to combine high
levels of performance and efficiency, and are well-suited to ensure sound reinforcement reliability in a wide range of venue
types. The DA-250D is ideal for dual-zone applications such as presentation and press-conference rooms, restaurants and
similar-sized locations. The DA-250DH is well-suited to such locations as exhibition halls, sports facilities, multipurpose halls
and houses of worship.

FEATURES

• High efficiency

Extremely high amplification efficiency of 80-90%, resulting in reduction in power
consumption by more than 60% compared with Class-AB amplifiers.

• Highly durable

Stands up to extended hours of operation. The DA amplifier has undergone a large
number of rigorous tests to prove its durability. In addition,TOA has been conducting
a “non-stop driving test” of the DA Series.

• High reliability

The DA amplifier has a comprehensive protection circuitry for protection against excessive
current flow due to overload, short circuit, unusual DC voltage output, and power amplifier
heat sink temperature rise ( over 100°C), temperature rise inside the unit (over 80°).

• Amplifier with lightweight design

Installation has become much easier thanks to the lightweight design.

• Compact design

The DA-250 Series is 1-unit size, and they can be efficiently mounted on a rack, so they
require only a small installation space. Because the amplifiers do not generate much
heat, 5 units can be stacked together in a rack.

• Independent power supply

Each of the channels has its own power supply. If the power supply of Channel 1 should
fail, this won't affect the operation of Channel 2. It is also possible to use the either
channel as a spare amplifier.

DA Series Amplifier

100

90
80
70
60
50
40

Efficiency (%)

30
20
10

0 2040 60 80 100

Conventional AB-class Amplifier

Output (%)

CU Version

DA-250D Frequency Response

[dB]

0

-1

-2

Output

-3

-4

-5
110100 1k 10k 100k

Frequency

1/8W 8Ω

1/8W 4Ω

DA-250D T.H.D vs Power Output

[%]

1.8

1.6

1.4

1.2

1

0.8

Output

0.6

0.4

0.2

0

-0.2

[Hz]

0.1 1 10 100 1k

4Ω 1kHz

8Ω 20kHz 8Ω 20Hz

4Ω 20kHz

8Ω 1kHz

Power Output

4Ω 20Hz

DA-250D Channel Seperation

[dB]

-65

-70

-75

-80

Output

-85

-90

ch2

-95

-100

[W]

10 100 1k 10k 100k

Frequency

[Hz]

DA-250DH Frequency Response

[dB]

0

-2

-4

-6

-8

Output

-10

-12

-14

-16

-18
110100 1k 10k 100k

Frequency

1/8W 19.6Ω

Efficiency vs Output

[%]

90

DA-250D (4Ω drive)

80

70

60

50

Output

40

30

20

10

0

020406080100

DA-250DH (19.6Ω drive)

DA-250D (8Ω drive)

Output

DA-250DH T.H.D vs Power Output

[%]

1.8

1.6

1.4

1.2

1

0.8

Output

0.6

0.4

0.2

40Ω 1kHz

0

40Ω 20kHz

-0.2

[Hz]

0.1 1 10 100 1k

[%]

Power Output

40Ω 50Hz

DA-250DH Channel Seperation

[dB]

-65

-70

-75

-80

Output

-85

ch2

-90

-95

-100

[W]

10 100 1k 10k 100k

Frequency

[Hz]

APPEARANCE AND DIMENSIONAL DIAGRAM

442 (17.4")

Rear View

482 (18.98")
465 (18.31")

Front View

401.8 (15.82")
371(14.61")

Side View

22.5 (0.89")

31.8 (1.25")

44

(1.73")

6.1 (0.24")

Unit: mm

ARCHITECTURAL AND ENGINEERING SPECIFICATIONS

DA-250D SPECIFICATIONS

The dual-channel power amplifier shall use class-D circuit topology and
shall be configurable to two channel operation. Power output in wo­channel mode with all channels driven shall be: 250W per channel into 4
ohms and 170W per channel into 8 ohms. Each pair of channels shall be
bridgeable to produce 500 W. Total harmonic distortion (THD) shall be
less than 0.1% @ 1 kHz, 0.3 % (20 to 20,000 Hz). The frequency response
shall be 20 to 20,000 Hz (±1 dB). The signal to noise ratio shall be 100 dB
(A-weighted). The crosstalk shall be 70 dB (A-weighted). The input
impedance shall be 10k ohms for each input into an electronically
balanced input circuit. Rear panel switches shall allow selection of
bridged operation for 1-2 channels. A rear channel input mode switch
shall allow the selection of input 1 to all mode, whereby the signal from
input 1 is simultaneously fed to other channel. Each input shall feature a 3
pin phoenix block and XLR connector. Rear panel output connector shall
be a heavy-gauge M4 screw-terminal barrier strip suitable for use with
spade lugs or up to #12 AWG bare wires. The front panel attenuators shall
be recessed to prevent accidental level changes and may be removed
and replaced by included security covers once levels have been properly
set. The front panel shall have two sets of four LED indicators to indicate
the following conditions: signal presence at input (greater than -20 dB),
signal presence at output (greater than 1 W @ 8 ohms load), peak clipping
and protection circuit activation. The front panel shall also have two
removable air filters that may be removed for cleaning without removing
the amplifier from the rack. The amplifier shall be forced-air fan cooled
with the air intake at the front and exhaust at the rear.
Built-in protection circuitry shall monitor voltage and current levels to
minimize potential damage from overloads, and disable output during
shorts, DC offset, or excessive operating temperature at power amp heat
sink over 212°F (100°C), or excessive operating temperature inside the
unit over 176°F (80°C) via a relay for each channel. The relay shall also
delay amplifier connection to the load during turn-on for about 2 seconds,
so as to prevent any occurrence of noise at turn-on. Power consumption
shall be 120 W (based on UL/CSA standards) and 650 W (rated output 4
ohms x 2 channels), and 420 W (rated output at 8 ohms x 2 channels).
The amplifier shall use only one standard rack-spaces or 1.75" (44.5 mm)
and its dimensions shall be 18.98" (W) x 1.73" (H) x 15.82" (D) (482 x 44 x

401.8 mm). Front panel finish shall be black anodized aluminum and case
finish shall be sheet steel. Weight shall be 11.02 lb (5 kg).
The amplifier shall be a TOA model DA-250D.

DA-250DH SPECIFICATIONS

The dual-channel power amplifier shall use class-D circuit topology and
shall be configurable to two channel operation. Power output in two­channel mode with all channels driven shall be: 250W per channel into

19.6 ohms (70V). A pair of channels shall be bridgeable to produce 500W
into 39.2 ohms (140V). Total harmonic distortion (THD) shall be less than

0.1% @ 1 kHz, 0.3 % (20 to 20,000 Hz) HPF OFF, and 0.3 % (100 to
20,000 Hz) HPF ON. The frequency response shall be 50 to 20,000 Hz (-3
dB, +1 dB) HPF ON. The frequency response shall be 20 to 20,000 Hz (±1
dB) HPF OFF. The signal to noise ratio shall be 100 dB (A-weighted).
The crosstalk shall be 70 dB (A-weighted). The input impedance shall be
10k ohms for each input into an electronically balanced input circuit. Rear­panel switch shall allow selection of bridged operation. The amplifier shall
operate in 2-channel mode when the switch is deselected.
A rear-panel input mode switch shall allow the selection of input 1 to all
mode, whereby the signal from input 1 is simultaneously fed to the other
channel. Each input shall feature a 3 pin phoenix block and XLR
connector. Rear panel output connector shall be a heavy-gauge M4
screw-terminal barrier strip suitable for use with spade lugs or up to #12
AWG bare wires.
The front panel attenuators shall be recessed to prevent accidental level
changes and may be removed and replaced by included security covers
once levels have been properly set. A dip switch on the rear of the unit
shall allow independent on/off selection of a 50 Hz (-6 dB/Oct) high-pass
filter (HPF) cut-off for protection against excessive low frequency loading
and saturation of speaker transformers.
The front panel shall have two sets of four LED indicators to indicate the
following conditions: signal presence at input (greater than -20 dB), signal
presence at output (greater than 1 W @ 19.6 ohms load), peak clipping,
and protection circuit activation. The front panel shall also have two
removable air filters that may be removed for cleaning without removing
the amplifier from the rack. The amplifier shall be forced-air fan cooled
with the air intake at the front and exhaust at the rear.
Built-in protection circuitry shall monitor voltage and current levels to
minimize potential damage from overloads and disable output during
shorts, DC offset or excessive operating temperatur at power supply heat
sink over 212°F (100°C) or excessive operating temperature inside the
unit over 176°F (80°C) via a relay for each channel. The relay shall also
delay amplifier connection to the load during turn-on for about 2 seconds,
so as to prevent any occurrence of noise at turn-on. Power consumption
shall be 120 W (based on UL/CSA standards) and 580W (rated output

19.6 ohms x 2 channels).
The amplifier shall use only one standard rack-space or 1.75" (44.5m) and
its dimensions shall be 18.98" (W) x 1.73" (H) x 15.82" (D) (482 x 44 x

401.8 mm). Front panel finish shall be black anodized aluminum and
case finish shall be sheet steel. Weight shall be 11.02 lb (5 kg).
The amplifier shall be a TOA model DA-250DH.
The optimal 1:1 line isolation transformer shall be TOA model MT-251H.

OPTION

MT-251H

4–5X7 (0.2" X 0.28")

66 (2.6")

94 (3.7")

122 (4.8")

97 (3.82")

108 (4.25")

Front View

Max. 80 (Max. 3.15")

Side View

Unit: mm

Matching Transformer

Designed for use with the DA-250DH Dual-Channel Power
Amplifier (option), the MT-251H electrically isolates the high­impedance speaker lines from the amplifier.

• Capacity: 0W – 250W

•Primary Side: 100V line, 70V line

• Secondary Side: 100V line, 70V line, 50V line, 35V line

• Frequency Response: 30 – 18,000Hz (+0dB, –3dB)

• Connection Terminal: M3 screw terminal, distance between barriers: 6.6mm (0.26")

•Dimensions: 108 (W) × 80 (H) × 122 (D)mm (4.25" × 3.15" × 4.80")

•Weight: 2.4kg (5.29 lb)

SPECIFICATIONS

Model DA-250D DA-250DH

Power Source 120V AC, 50/60Hz

Number of Channels 2

Total Output All Channel Driven 500W (1kHz, 4Ω) 500W (1kHz, 19.6Ω: 70V line)

Output Voltage per Channel 31.6V (1kHz, 4Ω) 70V (1kHz, 19.6Ω: 70V line)

Output Current per Channel 7.9A (1kHz, 4Ω) 3.6A (1kHz, 19.6Ω: 70V line)

Power Output

8 ohms per channel 170W —
4 ohms per channel 250W —
16 ohms bridged 340W —
8 ohms bridged 500W —

Hi-Z: 70V per channel — 250W
Hi-Z: 140V bridged, per channel — 500W

Power Consumption*

Idle power consumption 28W, 0.5A 35W, 0.7A

Rated power consumption

1kHz 8 ohms 420W, 5.9A —

4 ohms 650W, 8.7A —
70 Volts — 580W, 7.8A

1

1/8 Power Pink noise*

8 ohms 102W, 1.7A —
4 ohms 132W, 2.3A —
70 Volts — 147W, 2.3A

2

1/3 Power Pink noise*

8 ohms 197W, 3.1A —
4 ohms 308W, 4.4A —
70 Volts — 311W, 4.5A

1/8 Power 1kHz 8 ohms 84W, 1.4A —

4 ohms 112W, 1.8A —
70 Volts — 123W, 2.0A

1/3 Power 1kHz 8 ohms 160W, 2.5A —

4 ohms 222W, 3.4A —
70 Volts — 256W, 3.8A

Frequency Response 20Hz – 20kHz (±1dB) HPF ON: 50Hz – 20kHz (–3dB, +1dB)

THD 0.1 % (1kHz) HPF ON: 0.1% (1kHz)

S/N Ratio (A weighted) 100dB

Crosstalk at 10kHz (A weighted) 70dB

DC Offset* ±5mV

Voltage Gain* 29.5dB 35.1dB

Damping Factor* 100 (1kHz, 8Ω) 220 (1kHz, 19.6Ω: 70V line)

Inputs

Input impedance 10kΩ (unbalanced), 20kΩ (balanced)
Input sensitivity +4dB (1.23V)
Input clipping 14V (25.1dBu)

Protection Circuit Amplifier section DC output, overheat protection, load shorting, overload current, maximum output

Power supply section Overheat protection, AC rush current

Cooling Continuously constant speed fan with front-to-rear airflow,

Operating Temperature –10°C to +40°C (14°F to 104°F)

Operating Humidity Under 90% RH (no condensation)

Dimensions 482 (W) × 44 (H) × 401.8 (D)mm (18.98" x 1.73" x 15.82") (EIA Standard 19-inch rack mount width)

Weight 5kg (11.02 lb)

Finish Panel: Aluminum, alumite process, black

Accessories Euro style terminal block connector (3-pin) × 2, Tamper-proof cap × 2

Option — Matching transformer: MT-251H

0dB=0.775Vrms
*Typical data

1

*

1/8 power with pink noise represents typical program with occasional clipping.

2

*

1/3 power with pink noise represents severe program with heavy clipping.

340W (1kHz, 8Ω)

36.9V (1kHz, 8Ω)

4.6A (1kHz, 8Ω)

HPF OFF: 20Hz – 20kHz (±1dB)

0.3% (20Hz – 20kHz) 0.3% (100Hz – 20kHz)
HPF OFF: 0.1% (1kHz)

0.3% (20Hz – 20kHz)

50,000 hours life time at 25°C (77°F)

Case: Plated steel sheet

TOA Corporation

www.toa.jp

Specifications are subject to change without notice.

Printed in Japan (0803) 833-52-389-30 u