Output contour mod
This mod will give you a bit deeper bass response, at the sacrifice of a little of your wound strings clarity. The Direct drive uses a bass contour filter at the output of the PCB going to the left leg of the volume pot to give a response like a cranked EL34 output tube equiped amp. This mod will change the bass response from a "fat snarl with clarity" to a deeper 6l6 output tube like response.
Here are the glorious guts of the Direct Drive. The bass contour filter is a simple resistor capacitor network (RC network). We want to remove this RC network and replace it with a wire to give back some deep bass. Look to the upper right side of the PCB, notice the large green cap going from the PCB to the volume pot,. just remove the Cap/resistor and replace it with a jumper wire. You could also just "tack" (jumper from the PCB to the left leg of the volume pot)a wire around the RC without removing it.