[sdiy] tony clark's 8 step envelope

[Harry Bissell Jr]

Geezis, Tony...

why not use 4000 series c-mos. Then you won't
heat up the cabinet  :^P

H^) harry   (sea moss is cool and damp!)



--- Tony Clark <clark at andrews.edu> wrote:
> > http://www.wiseguysynth.com/larry/ahmw2004/14.jpg
> > 
> > This thing looks incredible. Any info on it Tony?
> 
>    Hi Mark,
> 
>    Sure, there's a bit of a write up on TGS here:
> 
>
http://www.the-gas-station.com/messages.cfm?type=normal&thread_id=57125&lastdays=60&
> 
>    And also on my DIY web page:
> 
>
http://www.physicsenterprises.andrews.edu/~clark/emusic/diy/
> 
>    But I'll repost here just so it's all in the
> archive...
> 
>    I call it the SVG, or Sequential Voltage
> Generator.  I designed it to 
> be a full 8-stage envelope generator with individual
> time and level 
> controls, but it does a few more things than that
> (more on that later).
>    Pretty much every EG has two phases, the attack
> phase (when gated) and 
> the release phase (when the gate is released), since
> the SVG can't really 
> be discussed in the typical ADSR frame, I'll simply
> refer to either the 
> attack phase or the release phase.
>    First, the length (number of stages) is
> selectable (and CV controlled).  
> It is marked by the RED led.  Also, the release
> stage is selectable 
> (CV'd) and is marked by the YELLOW led.  The current
> active stage is 
> marked by a GREEN led.  This alone allows you to set
> up any combination 
> of attack and release stages.  You could define up
> to 7 attack and 1 
> release stages, or 2 attack and 3 release stages, or
> any combination 
> thereof.
>    It operates pretty much like any EG.  When gated,
> it starts at stage 1 
> and increments until it reaches the stage BEFORE the
> defined release 
> stage.  It will sustain on this stage until the gate
> is released, at 
> which point it will cycle the release stages until
> the End stage is 
> reached.  As with most any EG, should you release
> the gate while in the 
> attack phase, it automatically jumps to the release
> phase.  And it will 
> also restart if gated during the release phase.
>    Unlike most EGs, the end level does not have to
> be zero, so in order 
> to facilitate the conventional start-from-zero,
> there is a reset mode.  
> You can have the SVG reset on the attack phase, and
> also have it reset on 
> the release phase.  This way the SVG can always
> start from zero, 
> regardless of what the end stage is set to.
>    The next fun feature is the loop modes.  You can
> loop either the 
> attack or release phases (or both!).  In the EG
> mode, if the attack phase 
> is set to loop and a gate is held, instead of
> sustaining at the last 
> stage (before the defined release stage), it will
> loop back to stage 1 
> and keep cycling until the gate is released.  If the
> release phase is set 
> to loop, then once the gate is released, then that
> portion will 
> continually loop until gated again.
> 
>    Trigger mode is similar to the EG mode except it
> is a one-shot and 
> ignores the release phase.  If you pulse the SVG, it
> cycles from stage 1 
> to the end stage.  If you keep it gated, it will
> loop.
> 
>    Sequencer mode is where things get a bit more
> interesting.  In this 
> mode, the internal timing circuitry is separated
> from the panel speed 
> controls, so that now the speed pots operate as lag!
>  But there's more!  
> As with the trigger mode, the SVG ignores the
> release stage setting and 
> runs from stage 1 to the defined end stage but does
> a continual loop.  
> However, if you turn the loop modes on, then the
> release stage breaks up 
> the SVG into two sequencer sections that can be
> toggled between by 
> gating!
>    The SVG also allows you to select between using
> the internal timing 
> circuitry (and control it with a CV) or use an
> external clock to drive 
> it.  If you use the internal clock and gate the
> external clock mode, you 
> can use this to start and stop the SVG sequence.
> 
>    That's the basics.  There's more fun to be had
> though.  Since I 
> included a common inputs to the level and speed
> circuitry, you can 
> transpose the level and speed of the whole SVG.  It
> should also easily 
> accept an audio signal into the level input so that
> you could use the SVG 
> as a sequencable lag processor.  And once I have the
> expansion panel 
> built, could also be used as a sequential switch.
> 
>    Speaking of expansion panels, I should note that
> there are so many 
> connections and inputs built into the SVG that I am
> having to make an 
> expansion panel to put all of the extra jacks onto!
> (things like 
> individual stage level and speed inputs).  There are
> a total of 47 CV and 
> 18 gate inputs (distributed amongst the jacks,
> switches, and pots).  
> Since I build everything to be CV and gate
> controlled, literally every 
> feature on the SVG can be externally controlled,
> from the release and end 
> stages, to gating the reset and loop modes.
> 
>    It's a beast of a module, and I'm still working
> some of the bugs out 
> of the logic system.  For those of you who think I'm
> nuts already for 
> using SMT, the SVG is controlled by good old 74xxx
> logic!  While it'd be 
> fun to do this stuff with a microcontroller, you
> absolutely can NOT get 
> better timing.  The only downside I've discovered is
> in power 
> consumption.  Definately a cabinet warmer.  :)
> 
>    Anyhoo, that's pretty much it.  There's still
> some work to do, but it 
> is a fun module.  I had loads of fun just setting it
> in sequencer mode 
> and then driving the end stage with an S&H noise
> source.
> 
>    Another thing for anyone interested, it WILL work
> as a standard ADSR 
> and only requires 3(!) of the 8 stages to do so. 
> Simply set END stage to 
> 3, Release stage to 3, set level stage 1 to max, set
> level stage 3 to 
> min.  Stage 1 speed is attack, stage 2 speed is
> decay, stage 2 level is 
> sustain, and stage 3 speed is release.
> 
>    Cheers,
> 
>    Tony
> 
>
-----------------------------------------------------------------------
>          The E-Music DIY Archive - New Site Coming
> Soon!
>
-----------------------------------------------------------------------
> 
> "We wouldn't want to ship something that doesn't
> work"
>    - Carl Stork, general manager, Microsoft Windows
> division
>      Excerpt from EE Times April 2, 2001
> 
>