MOTM

Sorry, this is long but worth it if you are interested in breath controller
in you MOTM set up.

OK, I have my breath controller mod up and working perfectly on one of my
official MOTM-850s.  As I play with this thing, I realize there are two
possible ways to hook this thing up (ones that don't actually modify the
850)..  Each seems to have advantages and disadvantages.

So, I would like to hear some feedback from those that are interested.
Fortunately, it is academic since the circuit works both ways.  Only one
resistor will change on the mod board depending on how you hook it up.

Method # 1 - I have the breath mod hooked into the same input as the pedal
input.  You can use either, but not really both at the same time.  The pedal
must be unplugged for full range operation of the breath controller.

Advantages of method # 1:
Since you use the same controls, you can produce (+) or (-) going CV with
the breath controller also.

Disadvantages of method # 1:
You have to drill a hole and mount the jack for the Yamaha breath controller
in your panel..  I have not yet found a 3.5mm (1/8") jack that will panel
mount in metal as thick as MOTM panels.  Any info would be appreciated.

The pedal voltage is reduced by about 3/10 volts by the modification.  This
could be solved easily by changing the pedal jack to one with a switch.

Method # 2 - The breath controller is wired into the MIX input instead of
the pedal input.

Advantages of method # 2:
You can use the MIX in jack for your break controller (with one of those
common headphone stereo 1/8 to 1/4 inch adapters)  So you don't have to
drill your front panel for a 1/8 jack and you don't need one of those crappy
small jacks on your MOTM panel.  The MIX jack does have to be changed to one
like the pedal jack.

You can use the pedal and breath controller at the same time (they add).

Disadvantages of # 2:
You can only have positive voltages for breath  since the MIX attenuator in
not attenuating.
You loose the mix in function for anything other than the breath controller
(unless you add the dedicated 1/8" dedicated BC jack with this method also.

I can share plans with you for a small modification PCB that will allow you
to connect your breath modification to with either 850 input using method #
1 or 2.  Only one resistor changes depending on you choice of connection.

Either of these methods can be implemented to your 850 for less than $10.
Neither require any modification of the 850 and are easily reversible.

Having said all that, let me describe my third option, which I think would
be cool too.  This is great for those that have two or more 850s (like me)
and are up for something a little more "professional" in the way of a
permanent modification.

In this modification, the breath controller does connect to the MIX input
location as above.  However, the MIX attenuator is changed to a reversing
attenuator like the Pedal range input.  The small add on PCB is slightly
different and the old MIX pot  (now breath control) gets moved to the new
PCB.  No modifications are required to the MOTM PCB, but the mix pot is
removed.  Then a Stooge panel is made to replace the 850 front panel that
has the graphics correctly identified on the bottom pot with reversing
markings, and the mix input is marked breath input.

I think this modification has the best of the two lesser versions.  But, you
do permanently loose the MIX input.  And, it is significantly more
expensive.  You would need a Stooge panel for $16 and a replacement mounting
bracket for $4 (unless you don;t care to correct the graphics).  The cost
difference of the electronics is nil.  I would be happy to pursue this
method if enough are interested.  It would set you back about $30 if you
DIY.

You know what is really cool sitting here using my 850 now... even when not
using the CV out, the cool gate out feature can be used to "tongue" a gate
on and off repeatedly.  Thanks to Paul for the foresight to add this useful
feature.

Any feedback would be appreciated.  I have mine now built as method # 1, but
I am thinking of changing it to method # 2 since an external reversing
attenuator could be used to get negative voltages from my breath control if
I wanted them.

One last thing.  I am willing to ship my modified 850 around for some beta
testing to a couple of others that have Yamaha breath controllers to use for
few days.  I have a BC-2.  But I would like to have others with a BC-1 or
BC-3 to try it out also.

Larry Hendry