MOTM

When going through some old boxes of stuff I found a non-working Apple II 
joystick (turned out just to be an open in the ribbon cable).  My immediate 
thought was to use it with my MOTM, so I ripped out the wiring, re-wired it, 
added the appropriate resistors, replaced the game buttons with X-Y 
switchcraft jack outputs, and now have nice joystick for MOTM use.  So if you 
find old joysticks laying around, they can still be useful.  Picture at:

http://members.aol.com/elhardt/joystick.jpg

-Elhardt

Hello,

There is some new info of the impending frequency shifter. The drawing on
the site is a mockup, but it does represent the current prototype. The big
change is the local quadrature oscillator is now uC based, but everything
else is still analog. The audio path is completely analog.

The new changes from the unit at NAMM (besides the inclusion of a uC) is
through-zero shifting and the quadrature oscillator's two outputs are
available for general use. They also have output level controls and LEDs
that show the intensity of the oscillator.

All comments are welcome. The graphics are not set in stone yet. What you
see is a mockup.

About the schedule: It is still unclear as to a specific ship date (it's
getting close). I am wrapping up the SurfaceOne design and that is taking a
LOT of time. That's the cause of the snail's pace on this frequency shifter.

Yes, the MOTM Expressionist is going to happen, and YES the original
Expressionist will get an update. I just need to clone myself...

Tony Karavidas
Encore Electronics

http://www.EncoreElectronics.com

Designers of "The best MIDI to CV converter on the planet." -Keyboard Oct.
1997

Thanks for that; it was well thought out and I'm considering all your
points...

Of course if any are implemented, it will be even longer before it's ready!!
;)


Tony

> -----Original Message-----
> From: media.nai@... [mailto:media.nai@...]
> Sent: Monday, July 22, 2002 9:39 AM
> To: Tony Karavidas
> Cc: motm@yahoogroups.com
> Subject: RE: [motm] Frequency shifter
>
>
>
> >There is some new info of the impending frequency shifter. The drawing on
> >the site is a mockup, but it does represent the current
> prototype. The big
> >change is the local quadrature oscillator is now uC based, but everything
> >else is still analog. The audio path is completely analog.
>
> That sounds good.  I'm all for increasing carrier suppression.
> That is the
> most important consideration.  I do not see why it would be necessary to
> use an analogue oscillator, as it's not meant to be heard.  While the
> entire thing could be done in DSP, I believe that keeping an all analogue
> signal path will improve both its sound quality and its resale
> value (since
> it cannot be duplicated in software).
>
> >The new changes from the unit at NAMM (besides the inclusion of a uC) is
> >through-zero shifting and the quadrature oscillator's two outputs are
> >available for general use.
>
> Imho, having at least one oscillator output is necessary in order to be
> able to tune the frequency shifter, and to do various parlour tricks.
> Having both outputs is even better as it can then be used as a stand-alone
> quadrature oscillator as well, which is a useful module in and of itself.
> Afaik, MOTM does not yet offer a self-resonating filter with separate
> outputs, which is the "traditional" way of generating sines in quadrature.
>
> So with the inclusion of through-zero shifting, this new hybrid
> seems to be
> a vast improvement over the previous design.
>
> >They also have output level controls
>
> I do not think that is necessary, and pots are expensive.
>
> >and LEDs that show the intensity of the oscillator.
>
> Yes, LED's could be useful to indicate activity at the beginning of the
> infrasonic range, and when using it as a quadrature oscillator.
>
> >All comments are welcome. The graphics are not set in stone yet. What you
> >see is a mockup.
>
> I agree that having controls for both initial and fine shift is very
> important -- imho, it would be nearly impossible to adjust the entire
> frequency range with only one knob.
>
> What scale is the CV input??  Perhaps two inputs, one exponential and one
> linear, would be much more useful, and more within the expectations of
> oscillator control used by the MOTM system.
>
> Also, if you wanted to make the oscillator uniquely useful in and
> of itself
> (whether or not it is being used with the frequency shifter), perhaps an
> input could be added so that it can be driven by the edge of an incoming
> pulse.  That way, everything from a quadrature LFO synced to an incoming
> clock, to exact shifting equal to the pitch of a 300, would be possible.
> No other module can do this, as I believe that it is simply not possible
> using analogue.
>
> Since the oscillator is already digital, it may be practical to add one or
> more features only possible in the digital realm.  Otoh, I have no idea
> whether this would be a simple matter of adding a jack and few lines of
> code, or a huge PITA.
>
> >About the schedule: It is still unclear as to a specific ship date (it's
> >getting close). I am wrapping up the SurfaceOne design and that
> is taking a
> >LOT of time. That's the cause of the snail's pace on this frequency
> >shifter.
>
> Don't worry, they say patience is a virtue, so we MOTM users are like
> saints compared the unwashed hordes clamoring over their 1/8" jacks :)
>
>
>

>There is some new info of the impending frequency shifter. The drawing on
>the site is a mockup, but it does represent the current prototype. The big
>change is the local quadrature oscillator is now uC based, but everything
>else is still analog. The audio path is completely analog.

That sounds good.  I'm all for increasing carrier suppression.  That is the
most important consideration.  I do not see why it would be necessary to
use an analogue oscillator, as it's not meant to be heard.  While the
entire thing could be done in DSP, I believe that keeping an all analogue
signal path will improve both its sound quality and its resale value (since
it cannot be duplicated in software).

>The new changes from the unit at NAMM (besides the inclusion of a uC) is
>through-zero shifting and the quadrature oscillator's two outputs are
>available for general use.

Imho, having at least one oscillator output is necessary in order to be
able to tune the frequency shifter, and to do various parlour tricks.
Having both outputs is even better as it can then be used as a stand-alone
quadrature oscillator as well, which is a useful module in and of itself.
Afaik, MOTM does not yet offer a self-resonating filter with separate
outputs, which is the "traditional" way of generating sines in quadrature.

So with the inclusion of through-zero shifting, this new hybrid seems to be
a vast improvement over the previous design.

>They also have output level controls

I do not think that is necessary, and pots are expensive.

>and LEDs that show the intensity of the oscillator.

Yes, LED's could be useful to indicate activity at the beginning of the
infrasonic range, and when using it as a quadrature oscillator.

>All comments are welcome. The graphics are not set in stone yet. What you
>see is a mockup.

I agree that having controls for both initial and fine shift is very
important -- imho, it would be nearly impossible to adjust the entire
frequency range with only one knob.

What scale is the CV input??  Perhaps two inputs, one exponential and one
linear, would be much more useful, and more within the expectations of
oscillator control used by the MOTM system.

Also, if you wanted to make the oscillator uniquely useful in and of itself
(whether or not it is being used with the frequency shifter), perhaps an
input could be added so that it can be driven by the edge of an incoming
pulse.  That way, everything from a quadrature LFO synced to an incoming
clock, to exact shifting equal to the pitch of a 300, would be possible.
No other module can do this, as I believe that it is simply not possible
using analogue.

Since the oscillator is already digital, it may be practical to add one or
more features only possible in the digital realm.  Otoh, I have no idea
whether this would be a simple matter of adding a jack and few lines of
code, or a huge PITA.

>About the schedule: It is still unclear as to a specific ship date (it's
>getting close). I am wrapping up the SurfaceOne design and that is taking a
>LOT of time. That's the cause of the snail's pace on this frequency
>shifter.

Don't worry, they say patience is a virtue, so we MOTM users are like
saints compared the unwashed hordes clamoring over their 1/8" jacks :)