Simple two stage CFA , has anyone seen such topology?

U130421

Disabled Account
2015-12-16 2:00 pm
Simple two stage CFA , has anyone seen such topology? I used low cost version of 240/9240 biasing 1A 24w but it gives very low distortion at 30W/20khz. This is just a "prova" design.
N.pass/Nakamichi has with k170/J74 if someone can remind me the reference.
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fab

Member
Paid Member
2004-03-24 1:16 am
Canada
fabaudio.online
You are welcome.
I suppose you are referring to the USSA5 amp. For the distortion- if that really matters :rolleyes: - see below real measurements at 1W and 6Wrms for 1KHz. Note that with H2 possible cancellation (not the goal here) THD would be about 0.002% of only H3 at 1Wrms. The CFA topology has a poor PSRR so you need a very good PSU. :rolleyes:

I have USSA3 with jfet input and USSA5 with bjt inputs. Both amps have their own different sound signatures, you choose which one you prefer.;)
One thing though is that jfet provides less gain than bjt as input stage so USSA3 has a lower damping factor than USSA5.

Fab
 

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