[sdiy] 555-based ADSR that refuses to work with 9v

[harrybissell]

does it work OK on +/-15 ???

There are some 555 circuits that work with one manufacturer
of 555 and not others. They are NOT all alike internally.

I had real troubles with the Chris MacDonald "MiniModular"
until he told me about the issue.  I don't recall whose
chip worked... but I had Motorola, Signetics, and National
chips... only one worked. It WAS a reset pin issue so beware

H^) harry

Karl Ekdahl wrote:
> 
> Hi all, i'm currently trying my luck adopting another
> René Schmitz design to 9v. The 555-based adsr2;
> http://www.uni-bonn.de/~uzs159/adsr2.png
> 
> I don't get the ADSR to work, it seems like the
> reset-pin doesn't like the non-reset VCC feed it gets
> from the transistors. It resets fine with the circuit
> given but it can't be set again unless i manually move
> the wire from Reset to VCC. Of course, i've measured
> the collector tied to Reset, and it is approx. 8.8V
> which should be more than fine as i understand it.
> 
> I just thought there might be some "magic" as with the
> noise source that i had to tie to -9 instead of GND.
> Btw, could someone explain that a little closer? JH
> mentioned the reverse breakdown voltage or "zener"
> voltage, BE, but that is stated to be 6V for a
> BC547...  ??
> 
> anyhow, help appreciated with the ADSR so i can finish
> this project!
> 
> Thanks
> 
> Karl