G.R.A.S. 12AD 1-Channel Power Module

Connection: Traditional 200 V
Channel(s): 1
  • 12AD 1-Ch Power Module
  • 12AD 1-Ch Power Module

Typical applications and use

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


The 12AD 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 microphone fitted to the preamplifier can be set to 0 V — for prepolarized microphones, or 200 V — for externally polarized microphones.

The 12AD also supplies ± 15 V to power the preamplifier. It will run for approximately 50 hours on fresh standard alkaline batteries. A Low Batt LED indicates the condition of the batteries.

The input is a 7-pin LEMO socket on the front panel, which is 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 signal from the preamplifier is AC coupled to the output which is a standard BNC socket also on the front panel.

Frequency response (±0.2 dB) Hz 0.05 to 200 k
Output channel(s) 1
Output impedance Ω 30
Linear mode Yes
Type Traditional power supply (LEMO)
Input channel(s), traditional power supply 1
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 35
Battery life h 50
Battery low indication Yes
Fuse mA 160 (slow)
Weight g / oz 520 / 18.342

Extension cables with 7-pin LEMO connectors

G.R.A.S. AA0008 3 m
G.R.A.S. AA0009 10 m
G.R.A.S. AA0012 30 m
G.R.A.S. AA0014 100 m
G.R.A.S. AA0020-XX Custom, XX specifies the length in metres


Extension cables with BNC connectors

G.R.A.S. AA0034 2 m
G.R.A.S. AA0035 3 m
G.R.A.S. AA0036 5 m
G.R.A.S. AA0037 10 m
G.R.A.S. AA0038 30 m
G.R.A.S. AA0039-XX Custom, XX specifies the length in metres