[sdiy] super simple portamento / slide / glide / slew limitingcircuit?

[David]

The Steiner follower was made for CVs. 

David

-- -----Original Message-----
-- From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
-- bounces at dropmix.xs4all.nl] On Behalf Of Todd Sines
-- Sent: Wednesday, July 13, 2011 2:32 PM
-- To: David G Dixon
-- Cc: synth-diy at dropmix.xs4all.nl
-- Subject: Re: [sdiy] super simple portamento / slide / glide / slew
limitingcircuit?
-- 
-- hi everyone,
-- 
-- Thanks all for the help.
-- 
-- But... maybe I wasn't clear..
-- 
-- This is intended to modify the Roland DG series CMU-810. It's essentially
an analog synth
-- tabletop expander that sounds a lot like an SH-101, MC-202 or SH-09.
-- http://matrixsynth.blogspot.com/2009/10/roland-cmu-810-compusynth-modded-
-- analog.html
-- [in the end I'd love mine to end up like this one, but for now, I just
wish to add
-- portamento]
-- 
-- What's different about this compared to the rest is that there's no
portamento of the
-- incoming CV / gate jacks.
-- So I'd like to cut the track for incoming CV, insert this _SUPER_ simple
portamento
-- circuit before it starts triggering the osc.
-- As I'm sure you know, Roland follows a linear pitch scale so I don't need
a switchable or
-- dual mode circuit.
-- 
-- Something about the first circuit from EM seems closer to what I need
[versus circuits that
-- need their own power, etc].
-- 
-- Is this helping or did I miss something from before? because it seems
like all of these
-- circuits are for much more complex applications, no?
-- 
-- Thanks... in advance!
-- 
-- 
-- +odd
-- --
-- On Jul 13, 2011, at 4:14 PM, David G Dixon wrote:
-- 
-- >> http://www.elby-designs.com/asm-2/glide/glide-asm2-about.htm
-- >>
-- >> Switchable lin and log response. One dual op amp, two
-- >> resistors, cap, pot, switch.
-- >
-- > I don't like that circuit at all!  The comparator will oscillate in
linear
-- > mode, generating about a 10V p-p sine wave at about 7400 Hz or so which
-- > takes a very long time to dampen out.  This will create high-frequency
-- > warble of several mV in the output.  I believe this circuit requires a
large
-- > resistor in the negative feedback loop of the comparator -- 100k gives
a
-- > smooth approach to the input voltage with rapid damping (less than half
a
-- > millisecond).  Also, the buffer benefits from a capacitive load
protection
-- > network.  Finally, the switch could be much simpler -- an SPDT will do
if
-- > it's hooked up properly.
-- >
-- > Again, email me privately for details.
-- >
-- 
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