King of the Stone Age? Cloning the Limited Edition Mad Professor Stone Grey

Back in February I built the AionFX clone of Mad Professor's Stone Grey Distortion pedal. It was a neat pedal, but the clone wasn't 100% accurate as I ended up using clipping diodes rather than transistors (essentially used as diodes) in the original. I also became aware of a limited edition version of the pedal and figured if I could figure out what changed in that version, it would make a far more interesting build! So, I did something fairly rare, I actually bought a pedal and set about trying to figure out what made it tick. 

Cloning the Mad Professor's Distortion

Despite the recent trend, I am actually still building clones of pedals that weren't produced by Boss. This build is based on the Aion Protolith, a clone of the Mad Professor Stone Grey Distortion. It was a fun (and quick) little build - especially in light of all of the recent complex pedals I've been building. The Stone Grey Distortion's lineage goes back to a circuit in a 1980s Japanese electronics book. This was adapted in 2009 by Bjorn Juhl and then sold to Mad Professor for general production in 2011. 

What's the Vector, Victor?

So here is my first "twin" build (well - sort of - we'll get to that later). I've been building several pedals lately (obviously) and I have a colleague who is also a guitarist looking for a delay pedal. Since I had the Aion Vector on my "to do" list, I didn't figure it would be too much more trouble to just build two at the same time, and for the most part that held true. It was sort of nice to be able to double check the placement of all of the components as I went through and make sure I didn't accidentally goof something up. The Vector is based on the Mad Professor Deep Blue Delay and the PT2399 delay chip. It is a digital delay, but one that many analog purists will at least tolerate. Unlike many of the pedals I've worked on, this one isn't ridiculously expensive, but it is still cheaper to build (~$40-50) than buy ($170-$200 used on reverb).