Schematic is avaiable HERE.
A few things keep in mind for experimenting…
The resistor across the Gain Boost switch is labelled 100k in the schematic which seem to be quite high.Try a smaller value for R2 or jumper it if you want to omit the Gain Boost switch altogether.
For a mor Trebkle Boost switch, increase the 56pF cap for a bigger value.
