ASM-2?

[Grant Richter]

Well, I am working on just such a board right now.
No VCOs or filter since those are best on there own PCBs.

Current circuit list goes like this:

Mike Preamp (probably a AD797 with switchable 10-100-1000 gain)
RIAA stereo preamp (for the DJ in all of us)
Envelope Follower (both ARP and Buchla styles with gate extractor)
Analog Noise generator (ala ARP 2600)
Psuedo Random Sequence Generator (4006)
Various weighted mixers for above (binary, semitone, whole tone, octave)
A balanced modulator based on the RC4200 (linearity 0.1%)
MIDI to DIN synch decoder (using John Blacets PIC, assuming John gives me
permission) 
with a divider afterwards to get 1ppq clock for analog sequencers
Inverter
Comparator
Joystick buffer amps
Sample and Hold (John Talberts design in Electronotes)
Four input DC coupled mixer
+10 volt reference
Voltmeter buffer amp (for the +/- 15 voltmeter)
Two manual LFOs

Did I miss anything?
This one will be available for DIY purchase through Wiard.

----------
> From: Sean Costello <costello at seanet.com>
> To: synth-diy at mailhost.bpa.nl
> Subject: ASM-2?
> Date: Thursday, July 15, 1999 12:06 PM
> 
> Hi all:
> 
> I've been bitten by the analog bug again, and have begun soldering in
earnest
> (as opposed to programming filters in C for Csound, which has been what I
have
> been working on for the past year or so). I have an ASM-1 PC board, and
am also
> working on various other circuits. I am starting to realize just how nice
having
> a PCB to work from is. The diode ladder filter is taking shape, but I am
getting
> sick of running all that bus wire around on the vectorboard...
> 
> I have a bit of a dream - a strange little nerd dream, but one that many
people
> on this list could probably relate to. :) It would be nice to have an
"ASM-2"
> PCB - a PCB that contains circuts that were not included on the original
ASM-1,
> that would be found in some of the nicer modular systems of the past. In
> addition, it would be great if the ASM-2 board could be used by itself,
as an
> audio processing system, or maybe as a simple stand-alone synth.
> 
> Some of the modules that I think would be useful in the ASM-2:
> 
> - Ring Modulator. Could be AD633 design, or a switchable VCA/RM as Ian
Fritz
> described in Electronotes (based on an LM13600).
> 
> - An additional VCO, similar to the ASM-1/Electronotes VCO, but with
additional
> triangle and sine outputs. Used with Ring modulator, or as an additional
VCO for
> an ASM-1 based system.
> 
> - Sample & Hold. 
> 
> - I guess an added noise generator would be useful to use the sample &
hold in a
> stand alone unit. This part of the PCB could be left blank if an ASM-1 is
part
> of the system.
> 
> - Preamp, for external signals. 
> 
> - Envelope follower (preferably with selectable attack and release
times). The
> LM3900-based design in the Electronotes PCC looks useful, as it has
different
> attack/release times, and can be used as an AR envelope generator if a
gate is
> applied. I'm sure that a standard quad op amp could be used in place of
the
> LM3900, as the various components of the circuit (preamp, full-wave
rectifier,
> buffer for AD capacitor, differentiator) could be constructed using
standard op
> amps.
> 
> - A voltage controlled slope generator-type thing, similar to the Serge
module,
> or the "trapezoid" generator on the VCS3. This would generate AD/AR
envelopes,
> as well as act as an LFO, where the AR envelope would cycle. Voltage
control on
> the attack and decay times would be included; voltage control of the
"off" time,
> as in the VCS3, would be very nice as well. 1 volt per octave control
over
> attack and decay times would be useful for using this circuit as an
additional
> oscillator. Anyone have any useful schematics? The Serge DSG seems really
> cool...
> 
> - A 4-pole lowpass filter. The Moog ladder is an obvious choice (probably
the
> best choice), but a 4-OTA/buffer structure might also be nice, especially
if it
> was switchable between lowpass and allpass. A temperature-compensated
expo
> generator, with linear FM, would be quite tasty.
> 
> - Comparator.
> 
> - Pulse divider (for suboctaves and other applications).
> 
> - Various utility modules - mixer, inverter, etc.
> 
> - Any sort of waveshaping circuits would be nice.
> 
> - Frequency shifter (well, this might be better as a circuit board on its
own).
> 
> I'm sure that there are plenty of other circuits that would be useful,
but it is
> a question of how many would fit on a circuit board. All of the modules
should
> follow the same standards as the ASM-1 modules, in terms of voltage
range,
> temperature compensation, general high quality, etc. 
> 
> So, anyone want to do this? ;) As I said, it is just kind of a dream of
mine - I
> wish I had the know-how to design something like this myself...
> 
> Sean Costello