The transistor used in this circuit is uncommon today. AC124 or equivalent such as AC188K and 2N2431 can be used. The circuit is from the 80's and makes use of transformers.
This circuit is based on a double operational amplifier of type NE5512 and is suggested by Philips...
The presented circuit uses an LM3900, transconductance operational amplifier. It was found in the...
This sensitive 4-transistor signal follower can be used in both audio and RF circuits. P1 is a...