This amplifier was found in a tube equipment manual from 1947. The high-fidelity circuit has pentode tubes at the output and a source with transformer.
The circuit shown is from the National Semiconductor's Linear Applications Handbook. The CI is not...
This circuit is from the Linear Circuits Application of Texas Instruments, using an operational amplifier...
Found in an RF Design from the 90's this circuit is intended for crystals of less than 1 MHz....