Found these posted by the one and only pinkjimiphoton on the usual places. Both are very old and rare always on fixed treble boosters. Should be quick fun small builds. You can easily make them NPN by flipping the electrolytic caps, power and ground connections. I believe low gain transistors will work fine in them.
FAL Treble Booster 1967
FAL Treble Booster 1969
