MOTM

i did moe's manual pushbutton gate mod and it works great.

http://motm.retrosynth.com/markus_stuff/motm800 mods


mark


At 06:55 PM 3/12/02 -0500, you wrote:
>For quite some time I've been contemplating a couple of enhancements to 
>the 800 ADSR generator.  The obvious "wants" are a manual gate switch (to 
>audition that portion of a patch), either a "gate on" LED or a gate output 
>LED (that tracks voltage level via intensity), and an adjustable gate delay.
>
>The gate LED has already been done 
>(http://www.hotrodmotm.com/800_mods.htm) and a manual gate switch is 
>pretty much cake, but the delay option is a little more involved.  Am 
>looking for opinions on the viability of this idea: Add the activity LED 
>like Moe did, add a manual gate switch as has been suggested by many, and 
>turn the SUSTAIN pot into a dual-use mode: SUSTAIN/DELAY.  I envision that 
>a multifunction piggyback board be added to the 800.  The manual gate 
>switch (an NKK switch to match other MOTM modules) is used to trigger a 
>gate on-demand.  But this added NKK switch would have a center-off, and 
>momentary On/On capability.  When the NKK switch is lifted, a manual gate 
>is created and the 800 module works as if a gate-in has been 
>received.  Let go of the added NKK switch and all is normal (gate goes 
>away).  But, press down on the added NKK switch and you have selected the 
>"delay-time-set mode".  Using the existing SUSTAIN pot, adjust for the 
>desired DELAY time wanted (1 millisecond to 10 seconds, log 
>curve).  Release the added NKK switch and the module works as normal 
>except that the added piggyback circuit "remembers" the selected delay 
>time and delays each incoming gate by the user-selected amount.  (Of 
>course the SUSTAIN pot will have to be adjusted back to where it was 
>before you adjusted the delay time.)  By again lifting the added NKK 
>switch, one can audition the delay time just added.
>
>Getting this to work is not difficult.  But would this be a workable user 
>interface?  (Yes, the SUSTAIN pot is linear... the conversion to a 
>log-taper for time-delay adjustments would be handled by circuits on the 
>piggyback board using a PIC processor, a couple of opamps, and some 
>passives.  And yes, just like a dedicated pot, the piggyback circuit would 
>remember delay settings even after the synth is powered down.  This 
>circuit is designed, but not yet prototyped.)
>
>Lastly, I would sacrifice the -ENV output in favor of a voltage control 
>input for the delay time.  That way, delay times could be made to vary by 
>note, random event, or anything else one could dream up.  This 
>modification would certainly require some hacks to the existing 800 
>module, but should be minimal in severity and number.  The changes would 
>be reversible.  I would suggest that a pair of MTA-156 connectors be added 
>to the piggyback board and use a short (3") MTA-to-MTA cable to supply 
>power to the 800 board to preserve use of the existing cable.
>
>In conclusion, one would end up with an 800 that has a manual gate switch, 
>gate activity LED, an adjustable gate-delay over a wide range of times, 
>and a gate-delay voltage-controlled input.  That, while adding only 2 
>small holes in the front panel of the MOTM 800 (LED and NKK switch).
>
>Comments?
>
>Cheers!
>Tom Farrand
>
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