Electret / Lavalier Stereo Microphone Preamplifier





I needed a way to make high-quality field recordings with my LOM mikroUši electret stereo microphones so I designed and built a battery-powered preamp.  The preamp boosts the mic gain by 30 db allowing for the mic to be connected using the “line in” jack on my various recording devices.  I’m now able to get very detailed field recordings with a low noise floor. Built to order.


Below is a sample recording using the preamp with my LOM mikroUši mics at the Norris Geyser Basin in Yellowstone National Park.




Specs:

  • Power: 9V battery
  • 3.5mm (1/8") stereo mini input
  • 3.5mm (1/8") stereo mini output
  • Features LM386 amplifier chips
  • Stereo “out” jack functions as on/off switch (when the output cable is unplugged the preamp powers off)
  • Mic Gain: 30dB
  • Dimensions: 1" x 2.5" x 3.5"


$70 USD with free domestic shipping