We found this preamplifier with 70 dB gain for microphones in American documentation from the 90's. Consumption is low and equivalent transistors can be used.
The circuit is from an Electronics Hobbyst Handbook from the 90s, being valid for panels of the...
This circuit can generate signals from 80 to 800 Hz with an amplitude of 0.3 V. We find it in a...
This circuit is from an American publication from the 60's. The power is on the order of 600 mW....