Actually, the Klon was not even on my radar. It was a rare pedal that I had no experience with yet. Very different circuits actually, but for some reason Klon people find that the Earth Drive provides a similar result, serves a similar purpose. It was surprised to learn of this actually. I finally got to mess around with a Klon, and really I loved it for some things. I wish I owned one. I think it would be a good companion to the Earth Drive. I do get why the Klon is so loved. It's pretty killer.
When we (my wife and I) developed the Earth Drive, we basically lined up about 12 boutique or revered overdrive pedals in our collection and just listened and took notes. We had a laundry list of things we liked and things we didn't like about each one. Not one of them made us totally happy. So really just from the descriptions and our want list I worked up a circuit to do what we wanted. It took a few rounds of tweaks, but then we felt like it was there. In a way, the Earth Drive is more neutral than most. Many pedals have a real strong EQ, a certain midrange frequency boost, maybe a curve in the low mids and a bass cut and also a treble cut. The Earth Drive is just really simple, more flat than most, simple voicing, a bit more bottom end than some, but no deep low mud, the top end is gently rolled off, not steeply dumped like many. Overall, just kind of a gentle and natural EQ approach. Then harmonically, the actual distortion/clipping harmonic content, that was mostly inspired by a Fender 6V6 or 6L6 push/pull amp driven hard, sort of.
... and it's just like any other day that's ever been...