Power modules

Why a Power Module?

An externally polarized condenser measurement microphone cannot work on its own.  It needs to be connected to hardware that can act as an interface between the raw signal output and the data acquisition unit or measurement device. The Power Module is such an interface that improves the performance and reliability of the measurement chain.

  • It provides polarization voltage for the transducer, ensuring that the microphone gets the charging voltage it needs.
  • It provides supply voltage for the microphone preamplifier. The preamplifier acts as a unity gain impedance converter. It provides a certain amount of line drive capability by providing a low output impedance and output current,  making it possible to transmit the signal from the transducer to the Power Module without significant degradation.
  • A power module can provide amplification or attenuation to the signal, thus making it possible to fine tune the measurement chain to the signals being measured and the  hardware being used.
  • Selectable filters make it possible to exclude unwanted noise from the measurement, e.g., wind-induced noise from outdoor measurements.
  • Overload detection makes it possible to validate the measurements and is a useful tool in monitoring setups.
  • When a Power Module with gain is used, you can use longer cables because of the power module's ability to deliver current.
  • A Power module introduces electrical isolation

GRAS' range of power modules cover solutions for electroacoustic applications (LEMO), intensity probes (LEMO), lownoise microphones (LEMO) and power modules with traditional power supply (LEMO) as well as power modules with constant current power (CCP) that have the ability to take advantage of GRAS SysCheck2™-enabled microphones.

GRAS 12BA, 12BE and 12BB CCP Power Modules with TEDS Support

Microphone power: CCP
Channel(s): 1, 2 or 4
TEDS via USB

GRAS 12BA, 12BE and 12BB CCP Power Modules with TEDS Support

12BA, 12BE and 12BB are 1-, 2- and 4-channel CCP power modules, respectively. They have SysCheck2™ and TEDS support and are powered by USB...

GRAS 12BC, 12BF and 12BD LEMO Power Modules with TEDS Support

Connection: LEMO
Traditional 200 V
Channel(s): 1, 2 or 4
TEDS via USB

GRAS 12BC, 12BF and 12BD LEMO Power Modules with TEDS Support

GRAS 12BC, 12BF and 12BD are 1-, 2- and 4-channel LEMO power modules, respectively. They have TEDS support and can be powered by USB or AC mains...

GRAS 12HF 1-Channel Power Module for Low-noise Systems

Connection: Traditional 200 V
Channel(s): 1

GRAS 12HF 1-Channel Power Module for Low-noise Systems

The GRAS Power Module 12HF is a power supply for single-channel, low-noise measurements using the matched, low-noise preamplifiers and high-sensitive microphones of a GRAS low-noise measuring system 40HF, 40HH or 40HT...

GRAS 12HM 10-Channel Power Module for Lownoise Systems

Connection: Traditional 200 V
Channel(s): 10

GRAS 12HM 10-Channel Power Module for Lownoise Systems

The GRAS Power Module 12HM is a 10-channel power supply for multi-channel lownoise measurements using the matched, low-noise preamplifiers and high-sensitive microphones of a GRAS 40HF, 40HH or 40HT Lownoise Measuring System...