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.
Q1,2.
Then Q3,5,7,9 for equal current sharing.
Ditto for Q4,6,8,10.
And the sum of Idss of Q3,5,7,9 should equal the sum of Q4,6,8,10.
Patrick
Then Q3,5,7,9 for equal current sharing.
Ditto for Q4,6,8,10.
And the sum of Idss of Q3,5,7,9 should equal the sum of Q4,6,8,10.
Patrick
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