The Mosfet Overdrive ships in its original "reactive" mode. In this mode, it interacts with your pickups, which is the main reason it "cleans up" so much from the guitar's volume control. However, putting other pedals (or wireless systems) between the Blackstone and the guitar will result in thin, harsh tone at high Drive settings. You can get away with putting a vintage-style wah in front, if you don't use it with the Drive controls near maximum.

But now the Blackstone includes a small internal switch that puts it in "buffered" mode. This permits unconditional use after other pedals, at the expense of the extraordinary "cleaning up" from the guitar controls. This used to be referred to as the "Buffer Mod", and was available at special request, but now it's standard.