Doepfer

Gents,

Now that I'm producing products on my own, I *guess* I'm 
supposed to become one of those internet placard signs for my 
own wares - but alas, I can't bring myself to that and when I run 
across truly functional design. I don't care what name is branded 
on it, I'm going to speak up.

I had an opportunity too good to pass on the other day and 
arranged for a barter trade in which i was the lucky recipient of a 
Doepfer Complex Envelope Generator. While I am too busy for 
sleep nowadays, this did not preclude me from spending a few 
moments with this instrument before having to go back on the 
rack..ah, solder bench.  

First, the A-143-1 is a thinking-persons instrument.  It runs very 
deep and best not approached for the first time after you've 
downed a beer because it will leave you totally befuddled.  This 
thing takes a focused mind to conquer! Being a Buchla head, I 
am always drawn to A/D envelopes first,. which is why I fancied 
the 143 over Dieter's quad ADSR.  This instrument exceeded my 
highest expectations.

Four independent A/Ds, which can be linked together in a 
plethora of different combinations - one after another, one during 
another, all linked, some linked - you name it.  The Comparator 
pulse out is dynamic - it has an external level pot which allows 
the user to select the reference voltage that will trip that signal, 
so you can fire a sync pulse at anytime in a given A/D cycle. - 
sweet.  

The A-143-1 also has one of my favorite features from the A. 
Systems RS60 -  a bipolar output level pot which will lets the 
user set the symmetry (offset) of the envelope's output full swing 
from null (center) to full positive (CW) or full inverted (CCW) and 
anything in between.  It should be noted that this offset is only 
available at the Mix output - the independent outputs for each A/D 
are internal set for full positive.  This arrangement takes a bit of 
creative thinking.  If you use this mix out, it will do just that - mix 
the outputs of the four A/Ds.  If however you only just want to 
utilize the offset feature of a single envelope, you need to connect 
the dummy patch cords (connected to nothing on the far end) 
into the other three A/Ds you wish to remain quiet.  This breaks 
the normaling and allows the user to select which of the four are 
present at the Mix output - one A/D, 2 - or 3.

Dieter has also equipped each with a self cycle switch.  One 
could do this with a patch cord by running the Comp out into it's 
own trigger in, but he saves you from using this output for that, 
freeing it for more interesting uses such as firing the others 
while cycling one or whatever.  But this is not to say the running 
the Comp out into the trigger input isn't interesting unto itself, 
because  at that point the treshold pot in effect acts like an 
overall duration setting for the A and D time dialed into the 
envelope itself - very handy.  By running the End of Attack out into 
the trigger in, the A/D behaves like a fixed voltage source.  
Turning the Threshold pot while in this configuration will give you 
a varying constant voltage at the A/D's output, much like the 
A-176.  Also handy.

Speaking of which - the End of Attack gate out gives you many 
options for creating complex envelopes by linking 2 or more A/Ds 
together - try doing that instead of relying on the internal 
normaling - it's an interesting variant.

True to A/D operation, the A-143-1 envelopes don't give a damn 
how long the incoming trigger lasts.  They look for the rising 
edge only and are not on-time dependant to the trigger input.  
This is what I like about A/Ds more than anything else. this 
makes them perfect for transients.

The range of each A/D is about 2ms to 10 seconds, exactly that 
of the Buchla quad function generators in which the A-143-1 is 
loosely based.   One thing the Doepfer unit doesn't have which I 
wish it did was VC of envelope overallduration, a decision which 
was proably due ot availible panel space...but seeing an extra bit 
of balnk on Env 2-4 , I may just have a poke around under the 
hood when I can and see if I may be able to a VC Input as a mod. 
.  Based on the time range available in each env,, I have a pretty 
good idea how Dieter did this - so I may have some luck here.  I'll 
let you all know.

OK - there is a billion other things to know about the A-143-1 but 
for me, no time to discover them presently. Maybe in a year or so 
when things aren't so hectic around here!  But in the meantime, 
I've got np idea how much credibility my recommendation carries 
- but I certainly would recommend this module to anyone and 
without any guilt doing so.

Dieter - good job!

- P