[sdiy] AHDSR schemo

[Scott Gravenhorst]

At least for a FatMan, the punch "hold" is a set length of time
created with a simple RC circuit.  I can see that it wouldn't be
very hard to modify most of the ADSR circuits I've seen this way. 
It would also be easy to make the H time adjustable by replacing the
resistor with an inline pot.

So if you want to design one, start by picking a favorite ADSR
design, then add an RC between the attack threshhold detector and
the flipflop.  Once the threshhold is detected, it outputs a logical
true, that starts charging the capacitor through the resistor.  Once
charged (again to the threshhold level), the flipflop is flipped,
but only after the punch hold delay.

Note that this probably won't work with 555 based designs because
you can't get between the threshhold detector and the flipflop.  But
there are many designs on the web which are done with an external
flipflop instead of a 555.

Yves Usson <yves.usson at imag.fr> wrote:
>Actually that's the track I'd follow if I'm bound to design my own 
>brand...
>The other solution is to clip the attack just has propsed at
>  http://www.synthesizers.com/egpunch.html
>
>Is it really useful to adjust the hold time or a simple hold switch
>with a 3Oms duration who do the trick ?
>
>YU
>
>> Just a naive suggestion : why don't you use a similar solution
>> as the part of the schematic producing the sustain segment ?
>> Then your module becomes ASDSR...
>>
>> JB
>-------------------------------------------------------------
>Yves Usson
>
>Lab. TIMC UMR5525 CNRS
>Institut d'Ingéniérie et de l'Information de Santé (IN3S)
>Faculté de Médecine
>Domaine de la Merci
>38706 La Tronche cedex
>
>email : yves.usson at imag.fr, yves.usson at ujf-grenoble.fr
>
>tel.  (+33) (0)456 520 074
>fax.  (+33) (0)456 520 022
>
>

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-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
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