LM13600

[harrybissell at prodigy.net]

The fet presents a high impedance to the Gm cell (which it likes... and a lower impedance to the buffer (which it likes)... This can make it similar to the LM13600...
(at increased component count). This might work better because the potential for control feedthrough is less.
:^) Harry


 ---- On Dec 31 Scott Gravenhorst <chordman at flash.net> wrote: 
> Harry Bissell <harrybissell at prodigy.net> wrote:
> >NJM (new japan ???) makes an LM13600... the LM13700 doesn't have access to
> >the bias points so you can't do it...
> >The LM13600 has lower buffer (darlington) bias current at low Gm, and
> >higher current at higher Gm... at the possible expense of feeding some
> >"thump" into the darlington as the Gm bias is varied (like VCA or VCF with
> >fast attack...)
> >The LM13700 has fixed bias for the buffer, alas... at too high of a value
> >to be really effective witlow Gm inputs...
> 
> I have read here of using a FET either between the buffer or in place of
> it.  Does this compensate for this effect in any way to make it more
> acceptable?
> 
> 
> -- Scott Gravenhorst	                | Linux Rex, Linux Vobiscum
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>