Does this FET buffer circuit look familiar?

homemade

Member
2004-07-22 3:42 am
us
I just got this completed board off ebay. $15 with shipping from China. Wondering if it looks familiar to anyone. Also curious if the design is any good. I'm hoping to use it as an output buffer for my cd player.
 

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juma

Member
2005-11-08 11:27 am
Zemun
Hi homemade,
that is cascoded complementary buffer, well known/used and nice performing circuit. Usually, it's made with 2sk170/2sj74.
2sk246/2sj103 are a bit different jfets (less transconductance).
Try it and tell us how does it sound
 

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Hi homemade,
that is cascoded complementary buffer, well known/used and nice performing circuit. Usually, it's made with 2sk170/2sj74.
2sk246/2sj103 are a bit different jfets (less transconductance).
Try it and tell us how does it sound
Hi
Is this buffer can work on Ucc=+/-9V or need something changed?
What needs to change the schematic to its input resistance is 1Mohm?
thank you
 

Itsmee

Member
Paid Member
2009-02-07 3:00 pm
Hi
Is this buffer can work on Ucc=+/-9V or need something changed?

Remove R1, R2, R7, R8, Q4 & Q8, fit links on the PCB in the Q4 & Q8 collector/emitter position.

What needs to change the schematic to its input resistance is 1Mohm?
Make R6 1M.

Take a look at the input of the F4 amplifier buffer in the Pass Labs forum, also have a look at the DCB1 buffer as an alternative.
 
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forr

Member
2004-12-01 6:46 pm
Next door
Strange cascode.
In Juma's circuit, the base voltage of each common base bipolars is half way between the output and the rail.
In Homemade's circuit, R2 and R7 are in series and not connected to the output.
Using this connection, a fet associated with its bipolar do make not cascode at all.