This circuit is from an Electronics World of 1968. The transistors are of the time and the power is supplied with a voltage of 40 V. The circuit is high fidelity.
Using only one LM107 operational amplifier, National Semiconductor suggests the circuit in the...
We found this circuit in a documentation from the 50's. The transistors are germanium types. The...
This circuit, from a 1974 publication, can be assembled with BC548 transistors. If powered with 6 or...