ETMC Technologies
agencies products solutions about us site map contact us news
    home   >   our agencies   >   G.R.A.S. Sound & Vibration   >   power modules  
Our Agencies

G.R.A.S. Sound & Vibration logo
 
Click here (or on logo) to go to G.R.A.S. Sound & Vibration web site.
 


Power Modules
 

G.R.A.S. has developed and manufactures a range of precision power modules to complement the capabilities of your microphones and pre-amplifiers:
 

Click on images for details:


Constant Current Power (CCP)   : :   G.R.A.S. Sound & Vibration


 

 
  Type 12AL
  Input Channels:
          1 x BNC socket 
  Output channels:
          1 x BNC socket 
  Transducer supply current:
          4 mA sourced from 28 V 
  Frequency response:
          1 Hz - 200 kHz 
  A-weighted network:
          IEC 60651 Type 0 
  Power supply:
          2 x AA alkaline batteries or 3 - 6 V DC 
  Comment:
          Low noise
          Switchable A-weigting
 		   AG0002  
  Comment:
          In-line adapter for connecting a CCP
          pre-amplifier (using BNC connection)
          to a constant voltage power supply
          (using 7-pin LEMO connection)
 

    CCP stands for "Constant Current Power" and describes G.R.A.S. power supplies that maintain a constant level
    of current for driving CCP transducers such as G.R.A.S. Preamplifiers Type 26CB (¼") and Type 26CA (½"), as
    well as the G.R.A.S. Array Microphones.

    Since current is constant, the only thing that can vary with an CCP transducer under excitation is the supply voltage.

    Furthermore, since power is supplied via the same line as that used by the signal, only a co-axial cable is needed
    for connecting the transducer to the power supply and subsequent analyzer.
 


Constant Voltage   : :   G.R.A.S. Sound & Vibration


 

 

 
  Type 12AA
  Input Channels:
          2 x 7-pin LEMO 1B connectors 
  Output channels:
          2 x BNC sockets 
  Gain settings:
          -20 dB, 0 dB, +20 dB, +40 dB 
  Preamplifier supply:
          28 V or 120 V 
  Polarisation voltage:
          0 V or 200 V 
  Frequency response:
          3.5 Hz - 200 kHz 
  A-weighted network:
          IEC 60651 Type 0 
  Output impedance:
          30 Ohm 
  Power supply:
          10 x AA alkaline batteries or
          12 - 18 V DC mains/line adaptor
          for 220/115 V 
  Comment:
          Built-in 1 kHz precision calibration
          generator with adjustable levels for
          both channels.
 		   Type 12AB
  Input Channels:
          2 via a 12-pin LEMO 1B connector 
  Output channels:
          2 x BNC sockets and
          one 9-pin D-sub socket 
  Preamplifier supply:
          28 V or 120 V 
  Polarisation voltage:
          0V or 200 V 
  Frequency response:
          0 Hz - 200 kHz 
  Power supply:
          10 x AA alkaline batteries or
          12 - 18 V DC mains/line adaptor
          for 220/115 V 
  Comment:
          Intensity Power Module for sound
          intensity probe Type 50AI
 		   Type 12AD
  Input Channels:
          1 x 7-pin LEMO 1B connector 
  Output channels:
          1 x BNC socket 
  Preamplifier supply:
          ±15 V 
  Polarisation voltage:
          0 V or 200 V 
  Frequency response:
          0.05 Hz - 200 kHz 
  Power supply:
          4 x AA alkaline batteries or
          4.5 - 24 V DC 
  Comment:
          portable, compact power module
 


 

 
  Type 12AG
  Input Channels:
          8 x 7-pin LEMO 1B connectors 
  Output channels:
          8 x BNC sockets and 2 x VXI sockets 
  Gain settings:
          0 dB, +10 dB, +20 dB, +30 dB,
          +40 dB, +50 dB 
  Preamplifier supply:
          28 V or 120 V (4-channel groups) 
  Polarisation voltage:
          0 V or 200 V (4-channel groups) 
  Frequency response:
          3.5 Hz - 200 kHz 
  A-weighted network:
          IEC 60651 Type 0 and IEC 61672 Class 1 
  Output impedance:
          30 Ohm 
  Power supply:
          110 - 240 V AC / 100 mA
          with 8 G.R.A.S. preamplifiers at 120 V 
  Comment:
          For multichannel acoustical measurements
 		   Type 12AK
  Input Channels:
          1 x 7-pin LEMO 1B connector 
  Output channels:
          1 x BNC socket 
  Gain settings:
          0 dB, +10 dB, +20 dB, +30 dB,
          +40 dB, +50 dB 
  Preamplifier supply:
          28 V or 120 V 
  Polarisation voltage:
          0 V or 200 V 
  Frequency response:
          3.5 Hz - 200 kHz 
  A-weighted network:
          IEC 60651 Type 0 
  Output impedance:
          30 Ohm 
  Power supply:
          10 x AA alkaline batteries or
          12 - 18 V DC mains/line adaptor
          for 220/115 V 
  Comment:
          Built-in 1 kHz precision calibration
          generator with an adjustable level
 		   Type 12AN
  Input Channels:
          4 x 7-pin LEMO 1B connectors 
  Output channels:
          4 x BNC sockets 
  Preamplifier supply:
          ±15 V  
  Polarisation voltage:
          0 V or 200 V  
  Frequency response:
          0.5 Hz - 200 kHz  
  Output impedance:
          30 Ohm 
  Power supply:
          4 x AA alkaline batteries or
          6 - 20 V DC mains/line adaptor
          for 220/115 V  
  Comment:
          Portable, battery operated
 


 

 

 
  Type 12AP
  Preamplifier Section:
    Input: 1 x 7-pin LEMO 1B connector 
    Output channels: 1 x BNC socket 
    Gain*:0 - 40 dB 
    Output Impedance: 100 Ohm 
    Bandwidth: 1 Hz - 200 kHz 
    Noise floor (rel. input): 6 µV RMS 20 - 20 kHz 
    Polarisation Voltage*: 0 V or 200 V 
    High-pass filter*: 1 Hz/20 Hz 
    Overload Detection*: red LED 

  Speaker-amplification Section:
    Input: 1 x BNC connector 
    Output: 1 x coaxial LEMO connector 
    Input impedance: 10 kOhm 
    Current output*: 1 x BNC connector 
    Gain*: -20 to +10 dB 
    Bandwidth (-3 dB): DC to 80 kHz 
    Phase shift (in/output) ±1°: DC to 30 kHz 
    Max. output voltage: ±14 V 
    Max. output current: ±1.4 A 
    Overload detection*: red LED 

  Power supply:
          110 V AC or 240 V AC 
  Comment:
          Power supply and conditioning amplifier
          for simultaneously powering a preamplifier
          for a condenser microphone and an
          amplifier for a loudspeaker

    *  Remote controlled
 

   Type 12AR
  Input Channels:
          2 x 7-pin LEMO 1B connectors 
  Output channels:
          2 x BNC sockets 
  Preamplifier supply:
          ±15 V 
  Polarisation voltage:
          0 V or 200 V 
  Frequency response:
          0.05 Hz - 200 kHz 
  Power supply:
          4 x AA alkaline batteries or
          4.5 - 24 V DC 
  Comment:
          Portable, battery operated
 		   Type 12AQ
  Traditional preamp. inputs:
          Connectors: 7-pin LEMO 1B
          Power supply: ±15 V or ±60 V
          Polarization: 0 V or 200 V 
  CCP inputs:
          Connectors: BNC coaxial
          Power supply: 4 mA sourced at 28 V DC 
  Signal inputs:
          Connectors: BNC coaxial
          Impedance: 100 Ohms
          Output: Floating or non-floating
          Overload level: 9 V peak 
  Gain:
          -20 dB to 70 dB in discrete steps of 10 dB 
  Filters:
          Lin: HP filter 0.56 Hz, -1 dB (2nd order)
          HP: HP filter 20 Hz, -3dB
              (butterworth 3rd order)
          AW: A-weighting, IEC 61650 type 0
          Ext.: Optional customised
              signal-response network 
  SysCheck:
          Output: Sinusoidal
          Frequency: 1,000 Hz
          Level adjustable: 0 - 5.6 V rms 
  Control interface:
          Interface to host. Smart RS232, MSG line 
  Power supply:
          Internal batteries: 6 x LR14 (C) alk. cells
          External power: 8 - 18 V DC 
  Comment:
          Constant Current & Constant Voltage
          2 channels
          Remote or manual control
          Each channel independent
 

    Measurement microphones and preamplifiers require special voltages for supply and polarisation.

    Acoustic measurements also often require special networks such as A-weighting or high-pass filtering; amplification
    or attenuation of the signal may also be necessary. These facilities are provided by the G.R.A.S. Power Modules.

    Standard externally-polarised condenser microphones require a stable polarisation voltage of 200 V DC for proper
    operation. This may be turned off in the power modules for use with prepolarised microphones.

    Low frequency acoustic signals generated, for example, by wind flow may overload the input section of the
    analyzer etc. This can be avoided by removing frequencies below 20Hz with the high pass filter in the power module.

    The A-network is the most frequently used frequency weighting method in acoustics. This approximates the
    sensitivity of the human ear, and the result is a measurement of the noise as perceived by the human ear.


    The G.R.A.S. Power Module Type 12AQ is a dual-channel power supply for preamplifiers (CCP as well as traditional)
    used with measurement, condenser microphones.

    It has facilities for both manual control and remote control. Manual control is via its front-panel switches and push
    buttons. Remote control is via its RS232 interface.

    The Type 12AQ is for general use in acoustic measurements as well as for intensity measurements; both in the
    laboratory and in the field.
 


Low Noise Measurement   : :   G.R.A.S. Sound & Vibration


 

 
  Type 12HF
  Input Channels:
          1 x 7-pin LEMO 1B connector 
  Output channels:
          1 x BNC socket 
  Output impedance:
          30 Ohm 
  Polarisation voltage:
          200 V 
  Power supply:
          4 x LR14 (C) internal cells or an
          external supply of 6 - 20V DC  
  Comment:
          Power supply for single-channel, low-noise
          measurements using the matched,
          low-noise preamplifiers and high-sensitive
          microphones of a G.R.A.S. low-noise
          measuring system.
 		   Type 12HM
  Input Channels:
          10 x 7-pin LEMO 1B connectors 
  Output channels:
          10 x BNC sockets 
  Output impedance:
          30 Ohm 
  Polarisation voltage:
          200 V 
  Gain adjustment/channel:
          ±3 dB 
  Channel separation:
          >90 dB 
  Power supply:
          115 or 230V AC, max. 35 VA 
  Comment:
          Power supply for multi-channel, low-noise
          measurements using the matched,
          low-noise preamplifiers and high-sensitive
          microphones of a G.R.A.S. low-noise
          measuring system.
 

    These are dedicated power modules for use only in G.R.A.S. low-noise level microphone systems.

    They provide polarisation and supply voltages for powering the special low-noise microphones and preamplifiers
    of these low-noise systems as well as the network for selecting a response setting of either pressure or free field.
 


 

Want to learn more or place an order?     Contact us .
 


 

Other G.R.A.S. Sound and Vibration products
ETMC Technologies Pty Ltd     Macarthur House, 8 Melville Street, Parramatta NSW 2150, AUSTRALIA
p: 02 9555 1225 (+61 2 9555 1225)     f: 02 8014 5198 (+61 2 8014 5198)     e: contact@etmc.com.au

    © 2009-2011,   ETMC Technologies Pty Ltd         All rights reserved

 
This page is best viewed with browsers set to at least 800 pixels wide.         Please report problems or bad links to webmaster.         Click here for site map.