[sdiy] ASM-1 Questions

[Magnus Danielson]

From: "Nihil Chimeraea" <nihil at torgoth.com>
Subject: [sdiy] ASM-1 Questions
Date: Wed, 22 May 2002 15:01:04 -0700

Hi!

> Hey, I've decided that once I can scrape up the cash for a PCB and
> the parts for a module or two, I'm going to start building myself an
> ASM-1, since it seems like it'd be cheaper than buying any of the
> better vintage semi-modular  analogs and is actually reasonably
> competitive in terms of specs, and had a few questions... 

Hey! Nice to hear!

> I'm hoping to get one of Paia's midi->cv converters and use that to
> control the device, and was wondering, is it on the right scale? It
> defaults to V/Oct, and while reading the info on Magnus' ASM-1 page,
> it never actually explicitly stated that it takes V/Oct for pitch
> control voltages, though V/Oct was mentioned on filters and things,
> so I thought it would be a good idea to ask just to be certain. 

OK, let's be specific: It's designed to take 1 V/Oct. You are a
resistor-change away to change that into any voltage per octave.

The PAIA MIDI-2-CV should be fine, except for the classical comments
about 8 bit D/As etc. that others will be happy to point out.

> And last... when grabbing the schematics off of Magnus' page, the
> files were labelled '1 of 7', '2 of 7', etc... but there are only
> five. Going by the circuit section listing on the page, it looks
> like the noise source and 'cv glide buffer' are missing... where are
> these? Also, the oscillater design was also marked '1 of 2'... is
> there a second page I'm missing, or is this an error?

Oh dear, oh dear, oh dear.... OK this is the story:

Look carefull at them schematics, cause what you see is not the output
of a CAD program or interactive picture program of either vector or
pixel type. No, I typed them in Postscript code. I made a component
library (took some effort, but was fun and boy, did I learn Postscript
basics quickly) and that's what I've been using. Editing schematics
like that isn't (allways) as fun as I originally thought. It can be a
head-ake. I ended up only doing 5 schematics that way. There is the
noise source schematic, which I did in gEDA... but I guess you only
find it if you use the right URL:

http://home.swipnet.se/cfmd/synths/friends/stopp/

Anyway, the real reason there is a few missing pieces is really me
being lazy like hell. The missing schematic is nothing but a pair of
op-amps, a pot and a cap. Big magic. An variable RC filter between a
pair of buffers.

Cheers,
Magnus