MOTM

>a) 3 pots, 6 jacks:

(jacks cost less than pots, LED's draw current and make noise)

1) UP
2) DOWN
3) HOLD

6 jacks:

1) UP
2) DOWN
3) HOLD
4) THRESH
5) OUT
6) SLEW

The time set by HOLD begins when the rising voltage reaches 5V or when the
falling voltage reaches 0V.  THRESH uses a switched jack.  With a jack
inserted into THRESH, and HOLD set to 0, the falling voltage begins when
the rising voltage reaches the TRESH voltage, the rising voltage begins
when falling voltage reaches 5V _minus_ the THRESH input voltage.  Got
that??  Since the falling voltage cannot reach 5V, if THRESH input is 0V
the cycle is not retriggered.  So if the input is a short trigger, it
cycles once then stops.  If the input is a gate, the falling voltage (or
hold) begins when the gate is released.  Note that HOLD also delays the
onset of an envelope.  Modulating THRESH with a voltage can produce various
functions, including a stepped function similar to S&H.

SLEW output is an output -- OUT run through a simple "degenerative emitter"
(but without the trimmers or current source).  It's more like a lag circuit
than true sine shaper to save space and money, but it will produce an
approximated sine if OUT is a triangle.

Features:
Makes tri, up saw, down saw, pulse, trapezoid, various functions, complex
LFO's, and a multitude of unique shapes.
No tempcos needed.
Cannot be replaced by a 320, 300, or 310.
Annoys people who already bought $erge and EM$ synths :)
Can also be used a VC EG.

Disadvantages:
"single sided" output.
No LED to indicate rate -- you'll have to use your ears, tough guy.
No simple "rate" control for tri waveforms (you need a mult).
No simple "PWM" for pulse waveforms (you need to modulate HOLD).

You could also build it with separate THRESH inputs for rising and falling,
lets call them RISE and FALL, and lose the SLEW output.

Just trying to get a "lock" on a variation of my own idea :)



At 12:21 PM -0500 12/05/01, mark@... wrote:

>
>>a) 3 pots, 6 jacks:
>
>(jacks cost less than pots, LED's draw current and make noise)
>
>1) UP
>2) DOWN
>3) HOLD
>
>6 jacks:
>
>1) UP
>2) DOWN
>3) HOLD
>4) THRESH
>5) OUT
>6) SLEW
>
>The time set by HOLD begins when the rising voltage reaches 5V or when the
>falling voltage reaches 0V.  THRESH uses a switched jack.  With a jack
>inserted into THRESH, and HOLD set to 0, the falling voltage begins when
>the rising voltage reaches the TRESH voltage, the rising voltage begins
>when falling voltage reaches 5V _minus_ the THRESH input voltage.  Got
>that??  Since the falling voltage cannot reach 5V, if THRESH input is 0V
>the cycle is not retriggered.  So if the input is a short trigger, it
>cycles once then stops.  If the input is a gate, the falling voltage (or
>hold) begins when the gate is released.  Note that HOLD also delays the
>onset of an envelope.  Modulating THRESH with a voltage can produce various
>functions, including a stepped function similar to S&H.
>
>SLEW output is an output -- OUT run through a simple "degenerative emitter"
>(but without the trimmers or current source).  It's more like a lag circuit
>than true sine shaper to save space and money, but it will produce an
>approximated sine if OUT is a triangle.

>I need "utilitarian", "cheap".

OK :)

>a) 3 pots, 6 jacks:

(jacks cost less than pots, LED's draw current and make noise)

1) RATE
2) FM
3) OFFSET

6 jacks:

1) FM IN
2) LFO 2 IN
3) TRI 1
4) TRI 2
5) SQ 1
6) SQ 2


Two linear tri LFO's, two square shapers, no tempcos, no sine shapers, no
LED, purposely unstable -- uses $5 worth of circuit board parts ;)

OFFSET and FM are reversing scaling attenuators.  OFFSET is normalled to a
positive voltage.

The input to LFO 2 is either LFO 2 IN  or the input to LFO 1 plus OFFSET
(using a switched jack).  When LFO 2 IN is used, OFFSET becomes its input
attenuator. This way you can patch the output of LFO 1 into LFO 2.

TRI 1 and SQ 1 use switched jacks -- unswitched, TRI 2 and SQ 2 contain the
sum of 1 and 2.  Offsetting SQ 1 to SQ 2 will simulate PWM.

Want a slow 1U saw??  Use a 310 or 800 :)

I like this idea. It's not just a dumbed down 320 but a whole new module.

At 12:21 PM -0500 5/12/01, mark@... wrote:
>  >a) 3 pots, 6 jacks:
>
>(jacks cost less than pots, LED's draw current and make noise)
>
>1) UP
>2) DOWN
>3) HOLD
>
>6 jacks:
>
>1) UP
>2) DOWN
>3) HOLD
>4) THRESH
>5) OUT
>6) SLEW
>
>The time set by HOLD begins when the rising voltage reaches 5V or when the
>falling voltage reaches 0V.  THRESH uses a switched jack.  With a jack
>inserted into THRESH, and HOLD set to 0, the falling voltage begins when
>the rising voltage reaches the TRESH voltage, the rising voltage begins
>when falling voltage reaches 5V _minus_ the THRESH input voltage.  Got
>that??  Since the falling voltage cannot reach 5V, if THRESH input is 0V
>the cycle is not retriggered.  So if the input is a short trigger, it
>cycles once then stops.  If the input is a gate, the falling voltage (or
>hold) begins when the gate is released.  Note that HOLD also delays the
>onset of an envelope.  Modulating THRESH with a voltage can produce various
>functions, including a stepped function similar to S&H.
>
>SLEW output is an output -- OUT run through a simple "degenerative emitter"
>(but without the trimmers or current source).  It's more like a lag circuit
>than true sine shaper to save space and money, but it will produce an
>approximated sine if OUT is a triangle.
>
>Features:
>Makes tri, up saw, down saw, pulse, trapezoid, various functions, complex
>LFO's, and a multitude of unique shapes.
>No tempcos needed.
>Cannot be replaced by a 320, 300, or 310.
>Annoys people who already bought $erge and EM$ synths :)
>Can also be used a VC EG.
>
>Disadvantages:
>"single sided" output.
>No LED to indicate rate -- you'll have to use your ears, tough guy.
>No simple "rate" control for tri waveforms (you need a mult).
>No simple "PWM" for pulse waveforms (you need to modulate HOLD).
>

-- 
------------------------------------------------------------------------
Scott Juskiw 
scott@...

This is remarkably similar to a module concept I've had for the last
year.  Sort of like a Universal Slope Generator, but with a Hold time
parameter.  I think you'll need an overall rate control though.

John Loffink
microtonal@...

-----Original Message-----
From: mark@... [mailto:mark@...] 
Sent: Wednesday, December 05, 2001 11:21 AM
To: motm@yahoogroups.com
Subject: [motm] proposed MOTM-390 uLFO



>a) 3 pots, 6 jacks:

(jacks cost less than pots, LED's draw current and make noise)

1) UP
2) DOWN
3) HOLD

6 jacks:

1) UP
2) DOWN
3) HOLD
4) THRESH
5) OUT
6) SLEW

The time set by HOLD begins when the rising voltage reaches 5V or when
the
falling voltage reaches 0V.  THRESH uses a switched jack.  With a jack
inserted into THRESH, and HOLD set to 0, the falling voltage begins when
the rising voltage reaches the TRESH voltage, the rising voltage begins
when falling voltage reaches 5V _minus_ the THRESH input voltage.  Got
that??  Since the falling voltage cannot reach 5V, if THRESH input is 0V
the cycle is not retriggered.  So if the input is a short trigger, it
cycles once then stops.  If the input is a gate, the falling voltage (or
hold) begins when the gate is released.  Note that HOLD also delays the
onset of an envelope.  Modulating THRESH with a voltage can produce
various
functions, including a stepped function similar to S&H.

SLEW output is an output -- OUT run through a simple "degenerative
emitter"
(but without the trimmers or current source).  It's more like a lag
circuit
than true sine shaper to save space and money, but it will produce an
approximated sine if OUT is a triangle.

Features:
Makes tri, up saw, down saw, pulse, trapezoid, various functions,
complex
LFO's, and a multitude of unique shapes.
No tempcos needed.
Cannot be replaced by a 320, 300, or 310.
Annoys people who already bought $erge and EM$ synths :)
Can also be used a VC EG.

Disadvantages:
"single sided" output.
No LED to indicate rate -- you'll have to use your ears, tough guy.
No simple "rate" control for tri waveforms (you need a mult).
No simple "PWM" for pulse waveforms (you need to modulate HOLD).







 

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At 11:06 PM -0600 12/05/01, John Loffink wrote:
>
>This is remarkably similar to a module concept I've had for the last
>year.  Sort of like a Universal Slope Generator, but with a Hold time
>parameter.

I'm not that familiar with the USG, but I guess great minds think alike :)

>I think you'll need an overall rate control though.

Is that necessary??  If the output is square, then HOLD controls rate.  If
the the output is saw, than either UP or DOWN (depending which way the saw
goes) controls rate.  If the output is TRI, then you need to use a mult on
both UP and DOWN.  The design isn't conducive to an overall rate control,
as it doesn't contain an oscillator.  Although I guess one could send a
common voltage to all three timimg parameters, but that would add another
jack.  Of course, one could add even more features and make it 2U.

I just discovered why so many MOTM messages are getting tossed. I have a
junk mail filter on Outlook and it scans for several things (I'm not allowed
to control the base list)

In the "Yahoo! Groups Sponsor" message below, it says "Order Now" and that
is one of the key phrases.

Stupid tools are supposed to HELP not hinder.

> -----Original Message-----
> From: John Loffink [mailto:microtonal@...]
> Sent: Wednesday, December 05, 2001 9:06 PM
> To: mark@...; motm@yahoogroups.com
> Subject: RE: [motm] proposed MOTM-390 uLFO
>
>
> This is remarkably similar to a module concept I've had for the last
> year.  Sort of like a Universal Slope Generator, but with a Hold time
> parameter.  I think you'll need an overall rate control though.
>
> John Loffink
> microtonal@...
>
>
> -----Original Message-----
> From: mark@... [mailto:mark@...]
> Sent: Wednesday, December 05, 2001 11:21 AM
> To: motm@yahoogroups.com
> Subject: [motm] proposed MOTM-390 uLFO
>
>
>
> >a) 3 pots, 6 jacks:
>
> (jacks cost less than pots, LED's draw current and make noise)
>
> 1) UP
> 2) DOWN
> 3) HOLD
>
> 6 jacks:
>
> 1) UP
> 2) DOWN
> 3) HOLD
> 4) THRESH
> 5) OUT
> 6) SLEW
>
> The time set by HOLD begins when the rising voltage reaches 5V or when
> the
> falling voltage reaches 0V.  THRESH uses a switched jack.  With a jack
> inserted into THRESH, and HOLD set to 0, the falling voltage begins when
> the rising voltage reaches the TRESH voltage, the rising voltage begins
> when falling voltage reaches 5V _minus_ the THRESH input voltage.  Got
> that??  Since the falling voltage cannot reach 5V, if THRESH input is 0V
> the cycle is not retriggered.  So if the input is a short trigger, it
> cycles once then stops.  If the input is a gate, the falling voltage (or
> hold) begins when the gate is released.  Note that HOLD also delays the
> onset of an envelope.  Modulating THRESH with a voltage can produce
> various
> functions, including a stepped function similar to S&H.
>
> SLEW output is an output -- OUT run through a simple "degenerative
> emitter"
> (but without the trimmers or current source).  It's more like a lag
> circuit
> than true sine shaper to save space and money, but it will produce an
> approximated sine if OUT is a triangle.
>
> Features:
> Makes tri, up saw, down saw, pulse, trapezoid, various functions,
> complex
> LFO's, and a multitude of unique shapes.
> No tempcos needed.
> Cannot be replaced by a 320, 300, or 310.
> Annoys people who already bought $erge and EM$ synths :)
> Can also be used a VC EG.
>
> Disadvantages:
> "single sided" output.
> No LED to indicate rate -- you'll have to use your ears, tough guy.
> No simple "rate" control for tri waveforms (you need a mult).
> No simple "PWM" for pulse waveforms (you need to modulate HOLD).
>
>
>
>
>
>
>
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

I need to switch to decaf :)

Anyway I gave this some more thought, and had a chance to look over the
schematics of the MOTM modules I have now.

Square is useful as a clock (although I would say a 310 is a better choice
than the 390 if you want a really stable 1U clock), but PWM isn't that
useful.  Saw without sync doesn't isn't that useful either, and you can
easily get saw out of other 1U modules.  Everyone seems to want sine.

So this is my revised version of a micro dual VC LFO:

~~~
>I need "utilitarian", "cheap".

OK :)

>a) 3 pots, 6 jacks:

(jacks cost less than pots, LED's draw current and make noise)

1) RATE
2) FM
3) LFO 2

6 jacks:

1) FM      2) LFO 2
3) SQ 1    4) TRI 2
5) SINE 1  6) 2 SINE


At it's core are two tri LFO's.  The second LFO (the one not used as a
clock source) is deliberately very unstable.  The module uses inexpensive
sine shapers (like the overdriven OTA's in the 410), no tempcos, no
exponential converters (although it might make sense to make RATE a log
pot), no "gold plated" op-amps, and no LED -- 100% low-budget.

LFO 2 and FM are reversing scaling attenuators.  LFO 2 is normalled to a
positive voltage.  FM could also be normalled, to a small voltage, and used
as a "fine" control.

The second LFO can be controlled in two ways by using a switched jack.
Without a plug, its input voltage is value of LFO 2 plus the voltage input
to the first LFO (which is the sum of FM and RATE), such that LFO 2 serves
as an offset, and FM and RATE serve as master controls for both LFO's.
When a plug is inserted into the LFO 2 jack, the LFO 2 knob becomes an
input attenuator.  This way you can patch either output of the first LFO
into LFO 2, or control each LFO independently.

SINE 1 uses a switched jack -- unswitched, 2 SINE contains the sum of both
sines (notice its name).  While the SQ 1 and TRI 2 jacks could also use a
summing feature, that might be confusing.