The Deimos project is identical to the original Tone Bender Mark 2 except for a couple of enhancements. First, a voltage inverter circuit has been added so you can use PNP transistors with a standard 9V supply. Second, it includes trimmers to more easily dial in the optimal bias voltage.
The dimensions of this pcb are 71mm x 58mm. It is also available as ready to solder kit:
This project is by Aion Electronics. Since the modifications featured in this project require some basic knowledge, this project is rather for more experienced builders.
Here is the direct link to the manual with layout and schematic: