PLAN B analog blog

Hi,

I am new to this group, located in Germany and a lucky owner of the Model Volt Proc, as my 
Cwejman S1 MkII is a bit short on freely accessible mixers, let alone crossfaders or 
Peak/Trough processors. To further enhance my setup, I am interested in the Model 37 Elf 
LFO and have a question about its waveform outputs: what's the voltage swing of each 
waveform, and which do swing around 0 Volt, and which do swing positive only?

Thanks much in advance,
Jan-Hinnerk

Hey Jan...

Welcome to the group.

All of the waveforms on the M37 are AC, swinging both sides of ground.  

That being said, know that the pulse width of the Pulse Out is severe. It'll trigger things like M10's, Miltons and Blacet EG1's that don't
give a hoot how long the incoming gate is to do their thing, but for
for ADSR's and such which are gate time dependent, forgeddaboutit.  

The Pulse is what happens to the normally square internal Reset signal
when the saw shaper is applied.  The method I've incorporated to
create the saw from the triangle core is a bit unorthodox...there are no output waveshapers. Instead I actually change the shape
at the core from Tri to Saw and that is reflected in the
pulse output at it goes from 50% duty cycle (tri setting) to somewhere around 4% (saw setting).

If you're one for waveform purity, stick with the Model 15.  For use
as an LFO, you won't notice a thing and when used as a VCO, given the
M37 outputs only the 'forgiving' waveforms - ones whose impurities are
not that audible - I get away with it.

hope this helps,

- P




--- In PLAN_B_analog_blog@yahoogroups.com, "metafoetus2002"
<jan-hinnerk.helms@...> wrote:
>
> Hi,
> 
> I am new to this group, located in Germany and a lucky owner of the
Model Volt Proc, as my 
> Cwejman S1 MkII is a bit short on freely accessible mixers, let
alone crossfaders or 
> Peak/Trough processors. To further enhance my setup, I am interested
in the Model 37 Elf 
> LFO and have a question about its waveform outputs: what's the
voltage swing of each 
> waveform, and which do swing around 0 Volt, and which do swing
positive only?

> 
> Thanks much in advance,
> Jan-Hinnerk
>

Hi Peter,

thanks for the welcome and the explanation. Is there an easy mod that would make just the 
sawtooth output swing positive only?

Best regards,
Jan-Hinnerk

--- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure that out)" 
<peter@...> wrote:
> All of the waveforms on the M37 are AC, swinging both sides of ground.

Wellll....

Hmmm...within the module it'll be a bitch, especially the Square/Pulse
port.  But you could add a couple of op amps, one just inverting with ground going to the reference input (in this case the +) and
the second also inverting,  yet with a trim pot going from the - and +
rail in the positive input insead of a ground reference.  That would
do it.

So internally you'd have to hang another little board and you'd route the one of the outputs (either the tri/saw or square/pulse), but first replacing it's 1K output resistor wth a 100K into the neg input of the first op amp with the positive input tied to ground, then use another 100K as it's feedback resistor, then the output of the first op amp through another 100K into the negative iput of a second op amp, use another 100K as that op amp's feedback, then the output of the second op amp through a 1K to the faceplate jack.  But instead of connecting the second op amp's reference (positive) input to ground, connect a trim pot which swings between full - and full + and that'll work as an offset so you can push the output waveform up and down vertically to the point it's fully offset on the positive end. 

Second option:  A model 14!!

Third Option:  A model 10 and use that for the positive LFO

I wish I could have done more with all of the ELFs...but those guys
are small and we had to make some hard decisions in all cases.

- P




--- In PLAN_B_analog_blog@yahoogroups.com, "metafoetus2002"
<jan-hinnerk.helms@...> wrote:
>
> Hi Peter,
> 
> thanks for the welcome and the explanation. Is there an easy mod
that would make just the 
> sawtooth output swing positive only?
> 
> Best regards,
> Jan-Hinnerk
> 
> --- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure
that out)" 

> <peter@> wrote:
> > All of the waveforms on the M37 are AC, swinging both sides of ground.
>

Hi Peter, 

yes, I guess it will be pretty packed inside the ELF LFO. Option 2 is nice, as I already have a 
Model 14. The only thing that bugged me is that I have to devote a complete 3-in-1-
bipolar-mixer with-offset to achieve just an offset.

I figure that you already get more than enough proposals on this list, but I can't help it, 
here comes mine: How an ELF Leveler MkII that (a) offers bipolar attenuation and uses 
pull-pots? If pot is pushed in, it's a bipolar leveler, if pulled out, it's a bipor level shifter. 
Guess it is out of the question as space is so small with the ELFs.

So back to reality (some sort of): option 3 is also nice, as I have long dreamed about 
adding one to my setup. I understand that there is now a Model 10 MkII around. I am 
trying to shut up here, but I can't: would it possible to add...a switch that changes between 
MkII (retriggerable) and MkI (non-retriggerable) behavior? And how about a three-way 
switch that switches the timebase VC into controlling T1 only, T2 only or TB (both, as it is 
now)?

I guess I've just turned into "The very hungry caterpillar" ;-)

Best regards,
Jan-Hinnerk 


--- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure that out)" 
<peter@...> wrote:

>
> Second option:  A model 14!!
> 
> Third Option:  A model 10 and use that for the positive LFO
> 
> I wish I could have done more with all of the ELFs...but those guys
> are small and we had to make some hard decisions in all cases.

I actually thought about a non-ac model 37 - but given it goes into
the audio range and beyond i felt it best to keep it both sides of ground.

Push pots - no can do in an ELF: too large under the panel.  The
iceberg effect would have the sides of the pot sticking out the ends
of the faceplate.

Model 10, Mk 3:  A switch for both retrig and non-retrig ops:  I
wrestled with this one, a lot and elected against it only becase it
would have constituted a rise in the price due to the time it would
take to wire the switch.  We've already got two of themin there we're
hand wiring as it is.  

If I convert the M10 to the new jacks, which means the panel hardware
would integrate by simply soldering the the part into a board, then I
will do this but in the meantime, ALL M10 MK 2's CAN BE MODDED IN THIS
MANNER.  You'll need to punch a hole in the panel and wre a DPDT
switch, but it can be done - I designed the new boards so tat was
possible.

This weekend I'll publish the procedure.

- P


--- In PLAN_B_analog_blog@yahoogroups.com, "metafoetus2002"
<jan-hinnerk.helms@...> wrote:
>
> Hi Peter, 
> 
> yes, I guess it will be pretty packed inside the ELF LFO. Option 2
is nice, as I already have a 
> Model 14. The only thing that bugged me is that I have to devote a
complete 3-in-1-
> bipolar-mixer with-offset to achieve just an offset.
> 
> I figure that you already get more than enough proposals on this
list, but I can't help it, 
> here comes mine: How an ELF Leveler MkII that (a) offers bipolar
attenuation and uses 
> pull-pots? If pot is pushed in, it's a bipolar leveler, if pulled
out, it's a bipor level shifter. 
> Guess it is out of the question as space is so small with the ELFs.
> 
> So back to reality (some sort of): option 3 is also nice, as I have
long dreamed about 
> adding one to my setup. I understand that there is now a Model 10
MkII around. I am 
> trying to shut up here, but I can't: would it possible to add...a
switch that changes between 
> MkII (retriggerable) and MkI (non-retriggerable) behavior? And how
about a three-way 
> switch that switches the timebase VC into controlling T1 only, T2
only or TB (both, as it is 
> now)?
> 
> I guess I've just turned into "The very hungry caterpillar" ;-)
> 
> Best regards,
> Jan-Hinnerk 
> 
> 
> --- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure
that out)" 

> <peter@> wrote:
> >
> > Second option:  A model 14!!
> > 
> > Third Option:  A model 10 and use that for the positive LFO
> > 
> > I wish I could have done more with all of the ELFs...but those guys
> > are small and we had to make some hard decisions in all cases.
>

Hi Peter,
thanks much, that's awesome!
Best regards,
Jan-Hinnerk

--- In PLAN_B_analog_blog@yahoogroups.com, "(i think you can figure that out)" 
<peter@...> wrote:

>
> Model 10, Mk 3:  A switch for both retrig and non-retrig ops:  I
> wrestled with this one, a lot and elected against it only becase it
> would have constituted a rise in the price due to the time it would
> take to wire the switch.  We've already got two of themin there we're
> hand wiring as it is.  
> 
> If I convert the M10 to the new jacks, which means the panel hardware
> would integrate by simply soldering the the part into a board, then I
> will do this but in the meantime, ALL M10 MK 2's CAN BE MODDED IN THIS
> MANNER.  You'll need to punch a hole in the panel and wre a DPDT
> switch, but it can be done - I designed the new boards so tat was
> possible.
> 
> This weekend I'll publish the procedure.

An attenuating offset Elf would be great!  :D
Could bring new life to many modules too.

-Don


--- On Tue, 11/11/08, metafoetus2002 <jan-hinnerk.helms@t-online.de> wrote:

From: metafoetus2002 <jan-hinnerk.helms@t-online.de>
Subject: [PLAN_B_analog_blog] Re: Model 37 Elf LFO Waveshape Question
To: PLAN_B_analog_blog@yahoogroups.com
Date: Tuesday, November 11, 2008, 1:48 PM










    
            Hi Peter,



thanks for the welcome and the explanation. Is there an easy mod that would make just the 

sawtooth output swing positive only?



Best regards,

Jan-Hinnerk



--- In PLAN_B_analog_ blog@yahoogroups .com, "(i think you can figure that out)" 

<peter@...> wrote:

> All of the waveforms on the M37 are AC, swinging both sides of ground.

will be mixer ever released?

thanks
best
r

ok, thanks for the answer


On 2008-11-12, at 14:38, robert piotrowicz wrote:

will be mixer ever released?

  thanks
  best
  r


www.musicagenera.net
www.myspace.com/robertpiotrowicz