Two more JH VCHADSR

[jorgen.bergfors at idg.se]

> > I have just completed two more copies of JHs envelope generator, with my punch feature added.

>I'm going to build this one too, I think.... but tell me, how is the
>Punch feature implemented?   And, have you done PCB's?  I will.

>Hallgeir

>Highly intriguing  --have you posted the circuit diagram somewhere
>to show how the punch kicks in --pun not intended?

>Yours,

>Hans Pelleboer

Hi all.

I have done a dual PCB, but no schematics yet. I haven't decided what to do with the schematic. As it is a minor extension, I could either redraw JHs entire schematic with the additions or just show the area where the extra parts should be added.
The additions consists of two more opamps after the original output and a couple of extra parts in the middle, to get a digital signal that is high only during the attack phase. This signal is added to the output signal -- that's what the extra op-amps do. Because the added digital signal saturates the opamp, the attack phase will just go to full-on immediately, ans stay there as long as the attack time is set. After that it will continue with the decay phase, as usual.
The punch can be cancelled, by grounding the digital signal. Then the envelope generator works as JHs original circuit.
I have also added variable threshold level. This is useful if you want to trigger several envelopes from the same signal. If you trigger them from a ramp and set the thresholds differently, they will fire in succession.
Maybe I will find time to put up a simple web site. If not, I'll try to at least make the schematic, and e-mail it to those who request it.

/Jorgen