G.R.A.S. 12AL 1-Channel CCP Power Module with A-weighting filter

Connection: CCP
Channel(s): 1

Typical applications and use

  • Power supply for CCP transducers and preamplifiers
  • General-purposes measurements
  • Precision measurements
  • Wide-band measurements
  • Switchable A-weighting network
  • Low noise
  • Battery operated


The 12AL will supply a transducer with a constant current of 4 mA. It has a wide operating frequency range from about 1 Hz (depending on load impedance) to well over 200 kHz. It also has an A-weighting filter which can be switched in or out.

The 12AL can be powered either by two internal AA alkaline batteries or from an external DC supply of 3 - 6 V. A regulated mains/line adapter AB0005 is available for supplying external DC power.

LEDs are used to indicate battery condition; green for power OK and red for battery low. Another red LED is used to indicate cable break, short circuit and overload.

The 12AL has zero gain since the output signal from the transducer is wired directly via 22 μF to the output connector. Zero gain is also preserved at 1 kHz when the A-weighting network has been switched in.

The size and weight of the 12AL make it a compact and handy power supply for CCP transducers both in the laboratory and in the field.

Frequency response (±3.0 dB) (with 10 kΩ load) Hz 0.7 to 200 k
Frequency response (±3.0 dB) (with 100 kΩ load) Hz 0.07 to 200 k
Output channel(s) 1
Output impedance, with A-weighting Ω 100 in serial with 22µF
Output impedance, without A-weighting Ω As source in serial with 22µF
Inherent noise, A-filter "on" and with dummy microphone (20 Hz to 20 kHz), µVrms 15
Inherent noise, A-filter "off" and with dummy microphone (20 Hz to 20 kHz), µVrms 4
A-weighting filter according to IEC 61651 Type 0
Linear mode Yes
Type Constant Current Power (CCP)
Input channel, CCP 1
Input channel(s), traditional power supply 1
CCP preamplifier supply @ +28 V mA 4
Overload indication Yes
Power supply, battery 2 x LR6 (AA)
Power supply, external Vdc 3 to 6
Power consumption mA 50 to 120
Battery life h 24
Weight g / oz 110.00 / 3.88
Weight with batteries g / oz 160 / 5,6
G.R.A.S. AB0005 Mains/line adapter