Hi Jed- what exactly are you looking to accomplish? To expand on what Barry said, the point of the 2KJ is to double the usefulness of one pot, if you will. For example on the MKC, you could put it on the gain and have two settings at the touch of a switch- perhaps a minimum gain and a maximum gain, for example. It might “feel” like an additional gain stage when you kick it up to max, but technically you’re still within the confines of the specs. The Afterblaster on the other hand, is an actual boost you can add on to the circuit.