Don's source follower

[Haible Juergen]

So ... the circuit is very "musical", and the only remaining drawback
would be the not-so-low output impedance.
What about a complemetary 2-stage follower, not with BJTs but MOSFETs
for the second stage ?
Either building an ordinary darlington configuration for each half (nJFET
source
follower into nMOSFET source follower, negative threshold voltage of JFET
and 
positive threshold voltage of MOSFET would sort of fit, but might have to be
matched),
ame for lower half with pJFET and pMOSFET.
Or maybe better, a "pseudo darlington" for each half, nJFET of upper part
gets
a drain resistor and the voltage across that goes to gate of pMOSFET, lower
half same with pJFET and nMOSFET.
Just an idea, neither tested not thoroughly thought over. But there is
something like
that with nJFET and pnpBJT for sure, so ...

JH.

> -----Original Message-----
> From:	Don Tillman [SMTP:don at till.com]
> Sent:	Wednesday, June 28, 2000 8:59 AM
> To:	edusilva at bahianet.com.br
> Cc:	synth-diy at node12b53.a2000.nl
> Subject:	Re: Don's source follower
> 
>    Date: Tue, 27 Jun 2000 10:47:05 -0300
>    From: Edu Silva <edusilva at bahianet.com.br>
> 
>    I remember I saw something about complementary source followers at
>    Erno Borbely website 
>    http://www.borbelyaudio.com/
> 
> Great, thanks!  He has a fascinating two part article about FET design
> on his web site.  It includes the complementary source follower
> complete with distortion measurements.  Excellent!
> 
>    and there's a nice Mark Levinson preamp (by John Curl) from 1973, with
> 2
>    JFET pairs in parallel at the output - the JC2
>    http://www.marklev.com/ 
> 
> Sure enough.  (Okay, I absolutely did not invent this thing!)
> 
>   -- Don
> 
> -- 
> Don Tillman
> Palo Alto, California, USA
> don at till.com
> http://www.till.com