MOTM

> From: Thomas Hudson <thudson@...>
> Driving cross country jonesing for my MOTM got me thinking
> about modules I wanted for specific functions, and then realizing
> that existing modules could already do those things, though
> not readily apparent. I know there are lot's or tricks I don't know
> about and I hope I can spark a thread about this.

I cannot think of a more intersting thread to get started right now.
<big grin>

> The one in particular for me was a comparator combo that would
> output -5 V whenever an input voltage exceeded the set threshold.
> I then realized that the 700 could handle the comparison function,
> but I didn't have a source of -5 V. Then I realized that I could
> take an 800, patch the plus out to the gate in, trigger it once and
> get it to hang in sustain mode, then take the minus output for
> my -5 V. I haven't tried this yet, since I'm still unpacking and
> haven't found the box containing my patch cables :-(.

You will be please to know that the 800 can be used as a voltage source
without this trouble.  Just plug NOTHING into gate or trigger.  The sustain
knob will give you  control of the voltage output at both + and - polarity.
Interestingly enough, if you set the attack and sustain levels up from zero
they will lag the change on the output when you turn the knob to a
predetermined change rate regardless of how fast you turn the knob.

> I'm sure there are non-standard uses of a lot of MOTM modules
> perhaps some of you share.

Yes, let's here it gents.
:)
Larry H

"J. Larry Hendry" wrote:

> > From: Thomas Hudson <thudson@...>
> > I'm sure there are non-standard uses of a lot of MOTM modules
> > perhaps some of you share.
>
> Yes, let's here it gents.
> :)

I'll add one more that may seem obvious to everyone else, but it
took me a while to realize. I wanted to invert a waveform and
thought it couldn't be done with the current set of modules.
I then realized I could use the ring mod with a negative voltage
into the Y input to invert the X input. Duh, it's a multiplier...,

Tomy

In a message dated 7/30/2000 11:31:35 AM, thudson@... writes:

>The one in particular for me was a comparator combo that would
>output -5 V whenever an input voltage exceeded the set threshold.
>

You want to let us know why you need -5V. It seems mildly exotic as compared 
to say a positive voltage, or a gate signal like +5V or +10V.

JB

I have a "pet" patch that I have always used to test the flexibility
of all the virtual software modular synths. Believe it or not,
most of the ones I've played with are incapable of producing
this patch, for lack of comparitor or logic modules (or restrictions
on control vs. audio). It is based on Craig Andertons Pulse
Width Multiplier. There is an input for a triangle wave and three
LFO's. The triangle is fed to one input of four comparators.
Comparator 1 is fixed to produce a square wave from the
triangle, the other three take each LFO as their other input. The
outputs of comparators one and two are exclusive-or'd together,
this output is x-or'd with comparator three, and this output
x-or'd with comparator four.

Patches like this are why I wish we had math and comparator
modules for MOTM.

Tomy

OK, now tell me how/why I would use such a path.  Remember, you are dealing
with the "modular challenged" here.  "mc" of course being the preferred
politically correct version of just plain stupid. :)
LH

----- Original Message -----
From: Thomas Hudson <thudson@...>

I have a "pet" patch that I have always used to test the flexibility
of all the virtual software modular synths. Believe it or not,
most of the ones I've played with are incapable of producing
this patch, for lack of comparitor or logic modules (or restrictions
on control vs. audio). It is based on Craig Andertons Pulse
Width Multiplier. There is an input for a triangle wave and three
LFO's. The triangle is fed to one input of four comparators.
Comparator 1 is fixed to produce a square wave from the
triangle, the other three take each LFO as their other input. The
outputs of comparators one and two are exclusive-or'd together,
this output is x-or'd with comparator three, and this output
x-or'd with comparator four.

Patches like this are why I wish we had math and comparator
modules for MOTM.

Tomy

jwbarlow@... wrote:

>
> You want to let us know why you need -5V. It seems mildly exotic as compared
> to say a positive voltage, or a gate signal like +5V or +10V.
>

Just toying with waveform mangling. With a ramp into both the CV and A inputs
on a 700, and -5 into the B input, I get a waveform whose positive is ramp
and negative is square or pulse. And it is an octave higher. Very similar to
a recent discussion on synth-diy.

Of course, now I want VC of the switch threshold on the 700.

Tomy

"J. Larry Hendry" wrote:

> OK, now tell me how/why I would use such a path.  Remember, you are dealing
> with the "modular challenged" here.  "mc" of course being the preferred
> politically correct version of just plain stupid. :)

You get sounds ranging from standard PWM to wild, grinding, distorted, bliss.
Very animated.

Tomy

----- Original Message -----

From: Thomas Hudson <thudson@...>

Just toying with waveform mangling. With a ramp into both the CV and A
inputs
on a 700, and -5 into the B input, I get a waveform whose positive is ramp
and negative is square or pulse. And it is an octave higher. Very similar to
a recent discussion on synth-diy.

Of course, now I want VC of the switch threshold on the 700.

----stoogly reply---------

Oh, that's easy.  Since the switch is VCed, to bias the threshold, just mix
your threshold VC and the ramp going into the CV input and put that sum into
the CV (unless I am missing something obvious).

But, if you really wanted that, it appears to me that VC of the switch knob
position would be an easy modification. BUT, enough of that hardware talk.

Larry H

In a message dated 7/30/2000 12:11:56 PM, thudson@... writes:

>Patches like this are why I wish we had math and comparator
>modules for MOTM.

Good point! If we only had some great general purpose modules, then we 
wouldn't be making pointless noise with our MOTMs -- it's all Paul's fault 
<g>. But I do agree that a comparator and some other general purpose circuits 
(e.g., inverter, bias voltage source) would make a great module, and that 
these types of unglamorous modules (too) often get neglected.

In a message dated 7/30/2000 12:20:04 PM, thudson@... writes:

>Just toying with waveform mangling. With a ramp into both the CV and A
>inputs
>on a 700, and -5 into the B input, I get a waveform whose positive is ramp
>and negative is square or pulse. And it is an octave higher. Very similar
>to
>a recent discussion on synth-diy.

I'd think that +5V into the B input would result in the same sounding 
waveform (inverted version of what you describe) if I follow your 
description, of course it's no easier to get +5V from a MOTM than -5V.


In a message dated 7/30/2000 12:23:41 PM, thudson@... writes:

>You get sounds ranging from standard PWM to wild, grinding, distorted,
>bliss.
>Very animated.

I'd bet there is a lot of great timbre modulation to be discovered with the 
700 given that it will switch well up into the audio range -- experimentation 
suggested here.

JB

What does a comparator do in a modular patch? Practical uses? Please help as 
I am planning to build a "Potpourri" module with a comparator in it and I am 
curious of it benefits and techniques required to use it. Thanks for your 
help,

Thomas White

PS. I highly recommend having a CV keyboard of some sort to trigger your 
MOTM without having to turn the MIDI converters on. Its rather liberating to 
play from my Roland M-181 and be able to use the pitch bend and analog 
portamento vs the Kenton I have used before (Still use for arrangements). 
Very smooth actions


>From: Thomas Hudson <thudson@...>
>Reply-To: motm@egroups.com
>To: motm@egroups.com
>Subject: Re: [motm] Non standard module uses
>Date: Sun, 30 Jul 2000 12:11:10 -0700
>
>
>I have a "pet" patch that I have always used to test the flexibility
>of all the virtual software modular synths. Believe it or not,
>most of the ones I've played with are incapable of producing
>this patch, for lack of comparitor or logic modules (or restrictions
>on control vs. audio). It is based on Craig Andertons Pulse
>Width Multiplier. There is an input for a triangle wave and three
>LFO's. The triangle is fed to one input of four comparators.
>Comparator 1 is fixed to produce a square wave from the
>triangle, the other three take each LFO as their other input. The
>outputs of comparators one and two are exclusive-or'd together,
>this output is x-or'd with comparator three, and this output
>x-or'd with comparator four.
>
>Patches like this are why I wish we had math and comparator
>modules for MOTM.
>
>Tomy
>
>

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It's a module; it has hundreds of uses. Right off the bat, it would turn any
simple waveform into a rectangular wave. It can also trigger events via
thresholds.

A VC one is more useful, and a Schmidtt trigger type even more so.

 -----Original Message-----
From: 	thomas white [mailto:djthomaswhite@...] 
Sent:	Tuesday, 01 August, 2000 1:04 PM
To:	motm@egroups.com
Subject:	Re: [motm] Non standard module uses

What does a comparator do in a modular patch? Practical uses? Please help as

I am planning to build a "Potpourri" module with a comparator in it and I am

curious of it benefits and techniques required to use it. Thanks for your 
help,

In a message dated 8/1/2000 10:06:24 AM, djthomaswhite@... writes:

>What does a comparator do in a modular patch? Practical uses? Please help
>as 
>I am planning to build a "Potpourri" module with a comparator in it and
>I am 
>curious of it benefits and techniques required to use it.

One very good use for a comparator is as a gate extractor for an envelope 
follower. The EF output goes into the comparator input and the comparators 
level is set to an appropriate level for the gate to come on. I point this 
out since having no comparator is a very obvious deficiency of the ARP 2600. 
As Ken pointed out, it is also the way to generate pulse waves and PWM.

If I'm not mistaken, you can get a very good idea how to build a comparator 
module by looking at the CV inputs of the MOTM 700, maybe adding an 
additional input on the other input of the comparator IC (an LM311 perhaps). 
Comparators are extremely useful when you start getting into more pulse 
driven modules (like sequencers and other logic modules).

JB