PMA said:
Am I missing something? AC coupling means zero current into gate resistors means Vgs =~0. FET's crash close enough to plus rail so Vds is low enough for .5mA at 0 Vgs? The distortion will be very bad at this operating point.
I general Hannes I agree the case for obsessive JFET matching is overstated. The folks that claim to get only 3 or 4 quads out of a bag of 1000 are shooting themselves in the pocket book.
Oh sorry, I forgot to post the link to above citations:
here it is:
http://www.diyaudio.com/forums/showthread.php?postid=1294772#post1294772
Have fun, Hannes
here it is:
http://www.diyaudio.com/forums/showthread.php?postid=1294772#post1294772
Have fun, Hannes
Hi Scott,
thanks for your comment!
Of course you're perfectly correct.
The circuit is mostly a result of my parts bin
and I think it's sufficient for the comparison as absolute values are not of interest.
(Don't tell anyone I'm using old scrap parts out of 80ies vintage gear )*
See, I'm matching jfets myself. Still and even if it's only for the beauty of symmetry.
My original intention was never to show that it's overstated. That came out of the data.
I just wanted to get a grip on what it could bring. There's so much discussion and so little real data.
Somehow I thought there would be more curiosity in finding things out. After all we seek real improvements, no?
In the end, building amps as a hobby has for a lot of people more to do with emotions than with rationale - and I'm no exception
Have fun, Hannes
*of course they get checked before use...
thanks for your comment!
Of course you're perfectly correct.
The circuit is mostly a result of my parts bin
and I think it's sufficient for the comparison as absolute values are not of interest.(Don't tell anyone I'm using old scrap parts out of 80ies vintage gear
)*See, I'm matching jfets myself. Still and even if it's only for the beauty of symmetry.
My original intention was never to show that it's overstated. That came out of the data.
I just wanted to get a grip on what it could bring. There's so much discussion and so little real data.
Somehow I thought there would be more curiosity in finding things out. After all we seek real improvements, no?
In the end, building amps as a hobby has for a lot of people more to do with emotions than with rationale - and I'm no exception
Have fun, Hannes
*of course they get checked before use...
h_a said:Hi Scott,
Crazy stuff! It would be interesting to see wether it also holds up on the bench
EDIT: err, 10Meg resistors. Are these these little things that change resistance already when touched?
Have fun, Hannes
Maybe on your own, personal little planet orbiting sometimes near the earth
No, that's just so I don't have to use any dirty electrolytic coupling caps.
10M are the biggest RN55C's that come standard in the assortment kits.- Status
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