We found this circuit in a Poptronics from the 90's. Equivalent operational amplifiers can be used. The circuit must be supplied by a symmetrical source.
This shield circuit is from an American documentation from 1969. The components can be modified...
This is an instrument amplifier that uses two resistive sensors. The circuit is suggested by...
This amplifier provides 20 W of power on each channel, containing separate filters to power a...