Josephson Engineering C550F

½” measurement microphone, 0.3 mV/Pa special order


Josephson Series Five microphones are rugged, stable and cost-effective alternatives to high voltage metal diaphragm lab mics for speaker testing, room acoustics, and general audio measurements between 20 Hz and 20 kHz. The 6mm condenser capsule has a permanently polarized backplate and a 3.5μm polyester diaphragm, metalized with a rugged nickel-chromium alloy. The frequency response is flat ±2 dB from 20 Hz to 20 kHz. Like all Josephson mics, the diaphragm is critically conditioned during manufacture for minimum drift over time. Series Five mics have been in rugged field service for more than twenty years, with little or no change in response. Several versions are available for use with a variety of other equipment.

The series is a “half-inch” model available in two sensitivity steps, each one covering an operating range of about 100 dB. The C550H provides 10 mV/Pa output, suitable for microphone level inputs. The Josephson Engineering C550F version has lower sensitivity, for use in very high sound level measurements. The frequency response is flat for on-axis sound incidence. All models may be powered with standard 24 to 48-volt phantom supplies, and provide symmetrical active balanced output. They will also operate on phantom power as low as 15 V with some reduction in maximum level. For more critical applications, please refer to model C617 in the Josephson Series Six, which has lower noise and higher overload point than the Series Five, uses lab-grade metal diaphragm mic capsules, and standard phantom power rather than the dedicated power supply required for most lab mics.


– Output Level, mV/Pa 10.0 0.3
– Dynamic Range, dB SPL
35-135 65 – 165
– Frequency Response
20 Hz to 20,000 Hz, ±2 dB
– Output Impedance
50Ω (recommended load 1kΩ)
– Operating Conditions
– Free-field
– Transducer Type
A capacitive pressure transducer,
pre-polarized backplate
– Power Requirement
Phantom power per IEC61938 P48,
Temperature Range, °C
– -10 to +50
– Weight, grams
– 140 Connector
– 3 pin XLR type, pin 2 positive polarity
– Accessories Supplied

Stand clamp, padded case 1- Individually calibrated at the factory
2- Per IEC 61672, with 48 V phantom power. 5 dB above the noise floor, to 5% THD
3- Specifications common to all Series Five models