The Formula No. 5 is a 5E3 Tweed Deluxe amp emulating overdrive pedal. It’s essentially 2 JFET stages (very similar to the AMZ Booster) with the Tweed Deluxe tone and volume (in this case gain) controls in between. A master volume pot is added at the output for more control. Here’s a great demo of this pedal from Just Nick, comparing it to an original Tweed Deluxe.
On the PCB I’ve added extra +9v and ground pads in case you build this with the DC jack at the top of the enclosure.