Solid-State-Relais (Triac über Optokoppler ansteuern)

This preamp is specifically intended for use with low impedance microphones; its advantages are high output level, large bandwidth and extremely low noise figure. The maximum gain of the preamp is approx. 200. Depending upon the sensitivity of the microphone used the gain can be adjusted by altering the value of resistor R3 (for which a suitable typical value is around 22 k).