A general purpose JFET-input operational amplifier incorporates well-matched, high voltage JFET and bipolar transistors in a monolithic integrated circuit.
I had a broken audio amp and decided just to replace all the pre-amp silicon. Cost about £15 total.
I used these op-amps as a better spec than the originals. Same pinout, I forget which ones I took out.
For convenience I soldered in sockets in case they needed changing again.
A really excellent result. That amp is really kicking it now.
