D1 bias currents

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Disabled Account
Joined 2005
I'm about to start matching mosfets for a D1 output stage and I'm sure I'm not reading/understanding the schematic correctly:

http://www.diyaudio.com/forums/attachment.php?s=&postid=231717&stamp=1062946522

from searching the archives I understand that R26 and R33 set bias for Q3 and Q6 respectively, and using the I = (V-3)/R formula I calculate a bias current of slightly more than 8mA.

For Q2 and Q5 am I right in assuming that R25 and R32 set bias current and that this is around 18mA?

cheers
Paul
 
Disabled Account
Joined 2005
Hi Nelson,

thanks for clearing that up. I'm trying to learn how to make sense of the schematics but it's a slow process!! So the network of R24, R21, and P4 set the gate of Q3 to approximately 15V?

btw I discovered your diy opamps article explained why fets give better performance than the mosfets in situations like the I/V. I really should read before asking dumb questions :\

cheers
Paul
 
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