The earliest version of the infamous HP was actually a dual silicon transistor circuit. It also had a few addons and a few big cap fifferncies compared to the later Ge/Si version. Not sure how it sounds but I guess some of might be interested to to try this one out.
The 2N3565 transistors had a quite wide gain range between 100-600 hfe so socketing might be a wise idea. I would start out withs 2N3904 or 2N5088s, just mind the pinout.
Schematic is avaiable HERE.
