[sdiy] Haible HADSR kerfuffle

Ben Bradley ben.pi.bradley at gmail.com
Wed Feb 27 06:15:44 CET 2019


Yes, there's not a conceivable op-amp circuit that has the + and -
inputs connected together. And yes, this op-amp does appear to have
some small amount of hysteresis. It looks to me that for proper
operation the negative input, pin 2, should NOT be connected to the
vertical line.

On Tue, Feb 26, 2019 at 11:56 PM ulfur hansson <ulfurh at gmail.com> wrote:
>
> hello list!
>
> i recently built Jurgen Haible’s voltage controlled HADSR, and looking at the schematics it looks like U6A is incorrectly drawn:
>
> http://jhaible.com/legacy/tonline_stuff/jh_vc_hadsr.pdf
>
> the op amp is there for hysteresis, right?
>
> in that case i would think one shouldn’t connect the negative input to positive...?
>
> i haven’t found anyone documenting a build of this design, so if you have ever attempted this i’d love to hear about your experience!
>
> as always, many thanks for your thoughts and comments :)
>
> all the best,
> -úlfur
>
> Sent from outer space
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