More Experiments - Envelope Generators this time...

The Old Crow oldcrow at Access.Mountain.Net
Wed Nov 22 22:22:47 CET 1995

On Wed, 22 Nov 1995 gstopp at wrote:

>  phases of the envelope's cycle. These switches all have some finite 
>  impedance which places restrictions on the time constant range - if you 
>  want longer maximum times this means a bigger cap and/or higher resistance 
>  pots. Pots become harder to get over 1 Meg. This means a bigger cap. This 
>  means that your minimum times get longer too. As you get into the tens and 
>  twenties of milliseconds your attack/decay/release times start to become 
>  noticeably sluggish. Not that this is bad, but it should be adjustable and 
>  not a design brickwall. Chip ADSR's use tranconductance amps internally. 
>  Discrete designs use discrete NPN and PNP transistors. The EN designs 
>  either use diodes or 4016/4066-type analog switches.

       I wonder how a TMOSFET would work here.  I use them all the time 
for power stages in variable-frequency 3 phase inverters; it seems like the
low-current versions would work fine as cap gates on the A/R stages (the 
on-resistance of a TMOS part is about 0.01 ohms.)  Never really thought about
any musical applications of them before...hmmm...


/*    Christopher S. Rider     */
/* */

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