Preamplifier Power Supply

For Low Noise and 200 V Microphones | Model 2221

The Model 2221 provides the highly stable DC polarization voltage required by precision microphones along with low noise amplification enabling it to drive input and output cables as long as 500 feet. It is rugged, light-weight and will provide up to forty hours of continuous operation(with PRM902 Microphone Preamplifier) using six AA internal batteries. It can also provide sufficient current to power the PRM903 Microphone Preamplifier, which has an internal heater.


  • 6 x AA batteries or DC adapter powered
  • 0 & 200 volt polarization
  • Selectable weighting (A, C, or Z)
  • Drive long cables up to 500 ft (150 m)
  • Settings retained when powered offSettings retained when powered off
  • Selectable gain (0 - 40 dB in 10 dB steps)
  • Overload indicator


  • In-House calibration of vibration instrumentation
  • Power a variety of precision microphones and preamplifiers
  • Signal conditioning for use with recorders, data loggers and analyzers