G.R.A.S. 12AR 2-Channel Power Module

Connection: Traditional 200 V
Channel(s): 2

Typical Applications and Use

  • General-purpose measurements
  • Two channels
  • Precision measurements
  • Acoustic monitoring
  • Microphone calibration
  • 0 V or 200 V polarization


The 12AR can be powered either by internal standard batteries or an external DC supply (4.5 V- 24 V), e.g. a mains/line adapter. It is built into a sturdy anodized aluminium cabinet.

The polarization voltage for the microphones fitted to the preamplifiers can be set to 0 V — for prepolarized microphones, or 200 V — for externally polarized microphones.

The 12AR also supplies ± 15 V to power the preamplifiers. It will run for approximately 30 hours on fresh standard alkaline batteries. A Low Batt LED indicates the condition of the batteries.

The inputs are two 7-pin LEMO sockets on the front panel, which are wired up for G.R.A.S. microphone preamplifiers, e.g. 26AB, 26AC, 26AJ and 26AK, but is also compatible with other available makes of similar microphone preamplifiers.

The signals from the preamplifiers are AC coupled to the outputs which are standard BNC sockets also on the front panel.

Frequency response (±0.2 dB) Hz 0.05 to 200 k
Output channel(s) 2
Output impedance Ω 30
Type Traditional power supply (LEMO)
Input channel(s), traditional power supply 2
Preamplifier supply V +-15
Polarization voltage V 0 / 200
Power supply, battery 4 x LR6 (AA)
Power supply, external Vdc 4.5 to 24
Power consumption mA 45
Battery life h 30
Battery low indication Yes
Fuse mA 160 (slow)
Weight g / oz 540.00 / 19.05
G.R.A.S. AB0005 Mains/line adapter