nothing in this application. BL grade parts have an IDss of 6-12mA, V grade from 10-20mA
The parts in this amplifier are run at 1mA so IDss isn't an important spec. Matching of V grade parts could be more difficult due to the wider possible range of IDss, but i havent tested to know.
I paid about 40 cents each for these parts nearly a decade ago, and today they can command up to $5 each. Inferior new replacements are going for $8 each limit 5 per person. If i had more, I'd be in the obsolete parts selling business instead of the amplifier building business.
nothing in this application. BL grade parts have an IDss of 6-12mA, V grade from 10-20mA
The parts in this amplifier are run at 1mA so IDss isn't an important spec. Matching of V grade parts could be more difficult due to the wider possible range of IDss, but i havent tested to know.
I paid about 40 cents each for these parts nearly a decade ago, and today they can command up to $5 each. Inferior new replacements are going for $8 each limit 5 per person. If i had more, I'd be in the obsolete parts selling business instead of the amplifier building business.
Justin already explained it, I recently purchased a matched quad of BL 2SK170/SJ74 and it cost me USD35. V grades are practically "unobtainium" in the market and only people who acquired them years ago will have them, V grade's higher Idss and transconductance will give an advantage in SQ for certain applications.
These JFETs are often found in the Nelson Pass (founder of Pass Labs and First Watt) designs and used as frontend input device, and are very popular in the DIY community.
Justin already explained it, I recently purchased a matched quad of BL 2SK170/SJ74 and it cost me USD35. V grades are practically "unobtainium" in the market and only people who acquired them years ago will have them, V grade's higher Idss and transconductance will give an advantage in SQ for certain applications.
These JFETs are often found in the Nelson Pass (founder of Pass Labs and First Watt) designs and used as frontend input device, and are very popular in the DIY community.
Aren't V grade only used in high current applications of which GS-X does not need?
Btw, Nelson Pass is like a DIYer on steroids. Love what he is doing with his First Watt company as he is still doing essentially DIY on the side even though he is the founder of Pass Labs. Shows his love of the field.
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