Part #: 247-001

Model: NAT247-001

Cobham - Audio Mixing Amplifier
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Part Number :

  • The Model 247 Audio Mixing Amplifier contains three electrically independent audio mixing circuits with four input channels and one output channel each
  • Designed for use as a multipurpose mixing amplifier for mixing Aural Warning, Cockpit Voice Recorder or virtually aircraft signals
  • Outputs from the Model 247 are designed to drive any impedance from 8 ohms up to 10K ohms
  • The Output power is limited by 100 ohms resistors on each output
  • Drives headsets to headset amplifier applications
  • The Model 247 standard configuration is designed for driving non-DC biased (ground referenced) loads
  • Includes bi-polar output capacitors for compatibility with DC biased loads such as DC



dimension: Height: 41.40 mm (1.63 in) maximum, Depth 76.96 mm (3.03 in) maximum, Width 76.96 mm (3.03 in) maximum excluding flanges, 102.36 mm (4.03 in) maximum including flanges weight: 0.6 kg (0.42 lbs.)
enclosure: Conversion coated aluminum Mounting: Bulkhead Mount: four # 8 screws
TEMPERATURE: -55° to +70° C Qualifications: RTCA/DO-160C Env. Cat. [A2F2]-BA(CL)XXXXXXZ(BZ)AAATZ(XXC2)XX
ALTITUDE: -15,000 to 70,000 ft. output impedance: 100 Ω
gain range: >12 dB DISTRORTION: <1% THD+N from 300 to 6,000 Hz
Frequency response: Flat within ±3dB from 300 to 6,000 Hz output: 4.5 Vrms (33mW) into 600 Ω, Outputs are current limited
mic bias: 18 Vdc at 30 mA (600 Ω source impedance) individually selectable power supply: 28 VDC at 150 mA maximum (each circuit) Maximum current (3 mixer circuits combined)= 450 mA
input impedance: 600 Ω (15K Ω with gnd/bias jumper removed) FAA: TSO-C50c (RTCA/DO-214 Class Ib, RTCA/DO-160C)
Part Number Description
247-001 Audio Mixing Amplifier   



Serial # P200277
Condition NEW
Mods None
Tag Date 08/06/20
Shop Chelton Avionics Inc.
Serial # P200267
Condition SVC
Mods -
Tag Date 07/27/20
Shop Chelton Avionics Inc.
- Audio Mixing Amplifier
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