jupiterjune said:As usual, I can't trust my memory when it comes to numbers. I used J174's in the mini-A, not J176's.
Ignoring good scientific method, I also changed the output devices at the same time that I dropped in the jfets. I changed from IRF634's to IRFP140's (checked that number).
I have 2sj74v (10-20MA) ( which are not as robust as the J174 ) . Still, I think they would be a choice in the MINI-A . If I calculated correctly there should be 15-18MA through Q1.
jupiterjune said:By reputation, the 2SJ74's are a really great jfet. (I don't own any). If you look at the noise voltage graphs on the spec. sheets of the two jfets, you will see the 2SJ74's have much lower (by at least a factor of 10) noise figures.
Even the better Siliconix jfets available from mouser don't come close (if the spec. sheets are to be believed). An Idss of 10 to 20 mA should be fine for a mini-A, and they should give much, much, better performance than the J174's.
Zen Mod said:
even if seems that even any sparrow hangin' in Pass forum knows that - I'll repeat , just in case :
Mini A is scaled down dreky Aleph 3 , or 30
Jfet Mini A can be scaled down dreky Aleph J
Aleph J use 2SJ109BL in input LTP
2SJ74BL is exactly half of 2SJ109BL
sandyhooker said:Only have eight of the devices ..seems they should be matched as they would be in the A-J . Doubtful I could get a match from only eight pieces needing two sets. Noone seemed to be interested in matched devices for the MINI-A. Why??