Doepfer

Hi Peter,

> There is a way to self oscillate a Doepfer ADSR if you have a 
tirgger modifier 
> module as well.  I do it all the time:
> 
> Positive out of ADSR into Trigger Mod.
> 
> Pulse out of Modifer into Retrigger in of ADSR
> 
> Put a cotat high voltage oce ito the gate iput of the ADSR ad 
remove it before 
> the cycle eds.

I don't have an A-165, but I assume that when you do this the re-
trigger level is at the mercy of whatever is inside the 165 which 
decides when it has seen a 'trigger'?

> As far as a mod to self osc, this would be easy:
> 
> Output of the ADSR through a comparitor, going into the - in.  The 
comp. + 
> reference set just a tad above ground (really really close to 
ground).  Output of 
> that through a switch to turn it off and on, output of that to a 
diode to the gate 
> or retrigger input.

Mmm, I can see a philosophical debate coming on about what a cycling 
ADSR really _is_. The 'mod' I've been playing with (I'm still 
pondering over it, because I keep having trouble deciding what is 
sensible and what is not, and this kind of comment reinforces this 
fact...) is almost exactly what you describe _except_ that the 
reference level will be the sustain level. Thus whereas with your way 
the ADSR swings through its full output range, my way it will only 
swing between the max output level and the sustain level, which 
perhaps is more flexible (?), i.e. it will be as your way when the 
sustain level is set very low. I've certainly had some great 'echo' 
like effects with it.

> This will give you an AR LFO as well.  It's a pain to self cycle an 
ADSR, 
> because it needs sustained gate input to complete the last two 
phases.

Not quite sure what you mean here - what I'm thinking of will only 
cycle _as long as_ the gate remains there. Since it re-cycles each 
time the sustain level is hit, there is no sustain phase per se, and 
when the gate closes, you get the release phase as normal.

My idea is actually working out a deal more simple than I thought, 
and in its simplest form will only require cutting 1 track, adding 1 
strap, and snipping through 1 resistor. I'm trying to organise a 
friend who has a digital camera so that when I do it I can post some 
pikkies. (There are also several pairs of diodes in the circuit whose 
purpose I haven't fully grasped yet, and I don't want to rush into it 
and overlook something....)

You've also made me want to check what happens if I switch it in and 
out via an A-150 _whilst the gate stays open_ to see if it restarts 
cycling when I switch it back in.

Tim