I've been doing a lot of research on JFETs and MosFETs lately and I discovered that if you run matched JFETs in parallel you can reduce the noise floor. So it got me thinking; sometimes we builders accidentally make "golden" versions of our pedals. Every once in a while an ideal version pops up, due to parts tolerances, accidental matching, phases of the moon, etc. Without completely desoldering everything and testing each part we don't really know why this happens. Normally we just send it on and a customer gets a really GREAT version of the pedal. During one of last year's Secret Chord builds I made one of these "golden" pedals. This time I was determined to figure out why.
So I did desolder and test every part and what I found is that both of the MosFETs VGS measured higher than normal, a lot higher, twice as high. So I batch sorted my MosFETs to see how often this higher VGS rating occurs, and it is about 1 in every 50. And to get a Secret Chord with BOTH MosFETs in that range is pretty rare. But that is what happened. Now this is not "free," with both MosFETs in the high range you get additional noise. This brings us back to the parallel JFETs.
I got to thinking; if you can reduce noise by paralleling matched JFETs, can I then use these higher VGS parts without additional noise? And the answer is a resounding "YES!" It freakin' works! BUT, finding and matching these rare higher VGS JFETs is a huge pain in the ass, and time consuming, and time = cost. So anyway to sum up, I know how to make "golden" Secret Chords now, and it won't happen very often LOL!
The dual parallel JFET "Enigma Edition" Oxide Secret Chord is dark and mysterious with our favorite copper knobs.