Hello Patrick,
I have a renewed interest in this circuit. I pulled out the initial boards I built last fall, removed the single 470uF polar cap, and added a pair of 1000uF bipolars. To my ear the change resulted in surprisingly good sound. I have ordered new boards that accommodate the larger caps, and am measuring JFETs while waiting for the boards to arrive.
I have enough devices to build two boards, where all 20 devices are Idss matched to within +/- 500uA . I'm not quite done, and with luck might be able to find enough that are Idss matched to within +/- 250uA.
My real question is how to use the closest matches? Would it be best to use closest matches in the Q9-Q10 positions? Or would it be best to use closest matches on the Q9-Q7-Q5... positions (and again in Q10-Q8-Q6... positions)? Regardless of this choice, I *think* I remember that Q10-Q8-Q6 positions should have a slightly higher Idss than the Q9-Q7-Q5 positions. Or maybe vice-versa. It's a very dim memory, and I can't find put my finger on any particular post.
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