Pro Audio Microphone Pre-Amplifier Using INA217 and OPA2137

Its simple Tiny Pro-microphone Pre-Amplifier using INA217 instruments amplifier and OPA2137 op-amp. Circuit has been designed using SMD components, 3 Pin female XLR connector has been used for direct micro-phone input.

The board has been design around INA217 low distortion, low noise instrumentation amplifier. The INA217 is ideal for low-level audio signals such as balanced low-impedance microphones. Many industrial, instrumentation, and medical applications also benefit from its low noise and wide bandwidth. Unique distortion cancellation circuitry reduces distortion to extremely low levels, even in high gain. The INA217 provides near-theoretical noise performance for 200Ω source impedance. The INA217 features differential input, low noise, and low distortion that provides superior performance in professional microphone amplifier applications. An OPA2137 op-amp used as a feedback to eliminate the offset voltage. Phantom power is not part of the circuit its just for reference. 


  • Supply Dual +/-15V DC
  • Output Unbalance Single Ended
  • PR1 Gain Adjust G=1+10000/Rg PR1









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