AETHERPHON, global theremin family

I have a keyboard (a K2600) that accepts both CC pedals and breath  
controller inputs.  I have done a few experiments where I have been  
able to convert Control voltages to midi-CC messages via the pedals  
however have been unable to find specs for the inputs anywhere.

I would like to send the CV signals from my Theremax and/or Epro to  
the Breath Controller or CC controller inputs -- if I can't get this  
to work I'll have to break down and purchase a CV to MIDI converter  
(such as the Paia Midi Brain).

Does anyone have specs or perhaps a schematic that allows CV outputs  
to connect to a digital keyboard such as the K2600?

Any comments/info greatly appreciated!

-- Kevin

Kevin,
If you want to use a CV to control the breath controller inputs of your
Keyboard, I think you are better of staying with an analog signal,
rather than a midi conversion due to midi's limited resolution, speed,
and likely not required.

I am researching the breath controller specs, but so far the best I can
find is 0v = 0 pressure, and I am not sure about that.  It seems to be
a dc voltage proportionate to pressure input, but I can't find a spec,
yet.

See if the manual for your keyboard indicates the breath controller
input voltage range.  My guess is the cv out from theremax/epro and
breath controller input are compatible, but that is a just a guess at
this point.

bret

--- kkissinger@... wrote:

> I have a keyboard (a K2600) that accepts both CC pedals and breath  
> controller inputs.  I have done a few experiments where I have been  
> able to convert Control voltages to midi-CC messages via the pedals  
> however have been unable to find specs for the inputs anywhere.
> 
> I would like to send the CV signals from my Theremax and/or Epro to  
> the Breath Controller or CC controller inputs -- if I can't get this 
> 
> to work I'll have to break down and purchase a CV to MIDI converter  
> (such as the Paia Midi Brain).
> 
> Does anyone have specs or perhaps a schematic that allows CV outputs 
> 
> to connect to a digital keyboard such as the K2600?
> 
> Any comments/info greatly appreciated!
> 
> -- Kevin
> 
> 
> SPELLBOUND-L, the glocal thereminist community
> 
> To contact the moderator, e-mail porphyrous@...
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> 
> 


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I wrote:

> I am researching the breath controller specs, but so far the best I
> can
> find is 0v = 0 pressure, and I am not sure about that.  It seems to
> be
> a dc voltage proportionate to pressure input, but I can't find a
> spec,
> yet.
> 
> See if the manual for your keyboard indicates the breath controller
> input voltage range.  My guess is the cv out from theremax/epro and
> breath controller input are compatible, but that is a just a guess at
> this point.

I downloaded the manual for the Kurzweil, and don't see a spec for
breath controller.  I do see that the input jack for breath controller
can also accepts a cc pedal.

Remember a cc pedal or a breath controller is an analog device.  It is
either a resistor, or a voltage source.

The kurzweil cc pedal has a tip, ring, sleeve (trs) connector.  This is
the same scheme used in the roland EV-5L pedal, that I have.  These trs
cc pedals are a pedal controlled potentiometer.  

I believe both are nominally 10k pots, but I know the roland has an
adjustment pot on the side to vary from about 8k to 50K (just measured
it).

The tip seems to be the wiper on the pot.  What some companies do is to
use this as a voltage divider.  The sleeve is ground, the ring is the
input voltage, the tip is output voltage.  The suggestion that kurzweil
does this is indicated here, regarding the k2500:

http://sonikmatter.com/wiki/Kurzweil:Dead_Letters_1996c
----------------------
(snip)

The rest of this document details more measurements on the Kurzweil
K2500.

I enabled the "Cped1" transmit (PitchBend) on the "Cpedal" page under
Setup and turned on "MIDI View Mode" under the Master Page to view the
MIDI values sent out during testing.

We've seen on this list that the connections for the pot are:

    Ring = One end of pot 
    Sleeve = other end of pot 
    Tip = Wiper 

I've been told by kurzweil@... (I think that's David Fox), that a
"standard" (is there one? :-)) 10K CV pedal will work on the K2500.

I used the previously-mentioned part from Radio Shack.

With 10K linear pot:

    Vts @ MIDI value 127 = 5V; It = 5uA 
    Vts @ MIDI value 0 = 0V; It = 0uA 

Ir was constant at about .6mA (as expected)

For grins, I tried a 100K linear pot. The results were the same as for
the 10K pot.

    Vts @ MIDI value 127 = 5V; It = 5uA 
    Vts @ MIDI value 0 = 0V; It = 0uA 

Ir was as expected (I didn't get an accurate reading, but it was just
over 50uA).

Additionally, varying the load on Ring to Sleeve from 10K to 100K does
not change Vrs.

Note the K2500 appears to prefer a full voltage swing on the Tip. That
is, for full MIDI value swing from 0-127, the Tip should go all the way
from the Sleeve voltage to the Ring voltage. Scaling using the K2500
firmware (Setup:Cped1:Scale/Add values) seems possible if the voltage
on the Tip is not full scale. 
--------------
end of clip

Kevin,

I believe the input voltage (from breath controller) to the k2600 is
the tip on the k2600 cc input.  I think that if you take a 3 conductor
(trs) cable, and plug it into the cv output  of the epro or theremax
(should be a 2 conductor jack), plug the other end into the k2600
breath controller/cc input, and assign that cc controller on the synth,
it will work.  

What this does is connect sleeve to sleeve, tip to tip.  Since the cv
output of the theremax and epro is a 2 conductor jack, there is no
ring, thus the k2600 ring is not connected (the supply voltage from the
k2600 to the breath controller or passive cc pedal).

It Must be a 3 conductor 1/4" cable (male to male), NOT 2 conductor
(that would connect the k2600 ring to sleeve, there is likely
protection for that, though) so that you have a ring on both ends.

Since I can't verify with a kurzweil here, I cannot 100% guarantee this
is correct, but the spock in me says that the probability of this being
correct is 99.77%.  Try at your own risk, or email/call kurzweil to
ask.

If you want to check things further, get a trs plug (radio shack) and
measure the voltages from tip to sleeve, and ring to sleeve to get a
better idea.  

I think you will see (as described above) the sleeve is ground, and the
ring is 5v dc.  Thus, the tip responds to the voltage connected (from
cc pedal or breath controller, or your theremin cv).

Email me directly if you need some assistance.  Let me know if you have
questions.   You can do this without going around your elbow with cv to
midi to synth midi cc.  Midi only has 128 levels, and has latency. 
Analog is continuous and immediate.

BTW, have you read this interview with Ray Kurzweil?  He is quite an
amazing thinker, and manages to make his thoughts into reality.

http://www.smart-publications.com/articles/MOM-kurzweil.php

bret





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Bret,

Thank you very much for taking the time to research the breath  
controller specs.

I expected to read +5v on the ring however I am reading -12v!  Not  
sure what to make of it.   When I apply a voltage to the tip, the  
K2600 does, indeed, generate midi CC messages -- however only a narrow  
voltage range (that I haven't been able to measure).

As you pointed out, the resolution of this input is only 0 thru 127,  
so would have limited utility.

Perhaps I should rephrase my question to the list:  how do you use  
your Theremin to control your MIDI devices?

-- Kevin

Quoting Bret <echoplex@...>:

> I wrote:
>
>> I am researching the breath controller specs, but so far the best I
>> can
>> find is 0v = 0 pressure, and I am not sure about that.  It seems to
>> be
>> a dc voltage proportionate to pressure input, but I can't find a
>> spec,
>> yet.
>>
>> See if the manual for your keyboard indicates the breath controller
>> input voltage range.  My guess is the cv out from theremax/epro and
>> breath controller input are compatible, but that is a just a guess at
>> this point.
>
> I downloaded the manual for the Kurzweil, and don't see a spec for
> breath controller.  I do see that the input jack for breath controller
> can also accepts a cc pedal.
>
> Remember a cc pedal or a breath controller is an analog device.  It is
> either a resistor, or a voltage source.
>
> The kurzweil cc pedal has a tip, ring, sleeve (trs) connector.  This is
> the same scheme used in the roland EV-5L pedal, that I have.  These trs
> cc pedals are a pedal controlled potentiometer.
>
> I believe both are nominally 10k pots, but I know the roland has an
> adjustment pot on the side to vary from about 8k to 50K (just measured
> it).
>
> The tip seems to be the wiper on the pot.  What some companies do is to
> use this as a voltage divider.  The sleeve is ground, the ring is the
> input voltage, the tip is output voltage.  The suggestion that kurzweil
> does this is indicated here, regarding the k2500:
>
> http://sonikmatter.com/wiki/Kurzweil:Dead_Letters_1996c
> ----------------------
> (snip)
>
> The rest of this document details more measurements on the Kurzweil
> K2500.
>
> I enabled the "Cped1" transmit (PitchBend) on the "Cpedal" page under
> Setup and turned on "MIDI View Mode" under the Master Page to view the
> MIDI values sent out during testing.
>
> We've seen on this list that the connections for the pot are:
>
>     Ring = One end of pot
>     Sleeve = other end of pot
>     Tip = Wiper
>
> I've been told by kurzweil@... (I think that's David Fox), that a
> "standard" (is there one? :-)) 10K CV pedal will work on the K2500.
>
> I used the previously-mentioned part from Radio Shack.
>
> With 10K linear pot:
>
>     Vts @ MIDI value 127 = 5V; It = 5uA
>     Vts @ MIDI value 0 = 0V; It = 0uA
>
> Ir was constant at about .6mA (as expected)
>
> For grins, I tried a 100K linear pot. The results were the same as for
> the 10K pot.
>
>     Vts @ MIDI value 127 = 5V; It = 5uA
>     Vts @ MIDI value 0 = 0V; It = 0uA
>
> Ir was as expected (I didn't get an accurate reading, but it was just
> over 50uA).
>
> Additionally, varying the load on Ring to Sleeve from 10K to 100K does
> not change Vrs.
>
> Note the K2500 appears to prefer a full voltage swing on the Tip. That
> is, for full MIDI value swing from 0-127, the Tip should go all the way
> from the Sleeve voltage to the Ring voltage. Scaling using the K2500
> firmware (Setup:Cped1:Scale/Add values) seems possible if the voltage
> on the Tip is not full scale.
> --------------
> end of clip
>
> Kevin,
>
> I believe the input voltage (from breath controller) to the k2600 is
> the tip on the k2600 cc input.  I think that if you take a 3 conductor
> (trs) cable, and plug it into the cv output  of the epro or theremax
> (should be a 2 conductor jack), plug the other end into the k2600
> breath controller/cc input, and assign that cc controller on the synth,
> it will work.
>
> What this does is connect sleeve to sleeve, tip to tip.  Since the cv
> output of the theremax and epro is a 2 conductor jack, there is no
> ring, thus the k2600 ring is not connected (the supply voltage from the
> k2600 to the breath controller or passive cc pedal).
>
> It Must be a 3 conductor 1/4" cable (male to male), NOT 2 conductor
> (that would connect the k2600 ring to sleeve, there is likely
> protection for that, though) so that you have a ring on both ends.
>
> Since I can't verify with a kurzweil here, I cannot 100% guarantee this
> is correct, but the spock in me says that the probability of this being
> correct is 99.77%.  Try at your own risk, or email/call kurzweil to
> ask.
>
> If you want to check things further, get a trs plug (radio shack) and
> measure the voltages from tip to sleeve, and ring to sleeve to get a
> better idea.
>
> I think you will see (as described above) the sleeve is ground, and the
> ring is 5v dc.  Thus, the tip responds to the voltage connected (from
> cc pedal or breath controller, or your theremin cv).
>
> Email me directly if you need some assistance.  Let me know if you have
> questions.   You can do this without going around your elbow with cv to
> midi to synth midi cc.  Midi only has 128 levels, and has latency.
> Analog is continuous and immediate.
>
> BTW, have you read this interview with Ray Kurzweil?  He is quite an
> amazing thinker, and manages to make his thoughts into reality.
>
> http://www.smart-publications.com/articles/MOM-kurzweil.php
>
> bret
>
>
>
>
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>
>
> SPELLBOUND-L, the glocal thereminist community
>
> To contact the moderator, e-mail porphyrous@...
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>

Kevin,
Don't know what to make of the -12v output on ring.  Not what I
expected, either.  I don't see much for cv to midi, mostly midi to cv. 
I have a kenton box that does that.  

So, looks like your first thought of the paia 9201fk MIDI Fader PROM
midi brain is a good choice.  It allows 0-5v input, and outputs into
'MIDI Control Change, Pitch Wheel and Channel Pressure messages'.

There are some DIY projects like
http://tomscarff.tripod.com/cv2midi/cv2midi.htm
and more elaborate (multi channel) and expensive cv to midi
http://www.electrovoce.com/Applications/cvmidi.html
http://www.bigcitymusic.com/product.asp?cat=new&pid=1000314

Good luck.
bret

--- kkissinger@... wrote:

> Bret,
> 
> Thank you very much for taking the time to research the breath  
> controller specs.
> 
> I expected to read +5v on the ring however I am reading -12v!  Not  
> sure what to make of it.   When I apply a voltage to the tip, the  
> K2600 does, indeed, generate midi CC messages -- however only a
> narrow  
> voltage range (that I haven't been able to measure).
> 
> As you pointed out, the resolution of this input is only 0 thru 127, 
> 
> so would have limited utility.
> 
> Perhaps I should rephrase my question to the list:  how do you use  
> your Theremin to control your MIDI devices?
> 

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