[sdiy] Roland CR-8000 triggering

Travis Thatcher recompas at gmail.com
Sat May 23 16:01:57 CEST 2015

I built one for my CR5000 using an Arduino. Its a bit crude but does
the job really well, also does Midi-sync and Din Sync out. I have a
switch to turn off the midi control of the clock so it just does
triggering or can use the internal clock. The cool thing is that if it
is under midi clock control you can still sequence it and use the
patterns at the same time.


On Sat, May 23, 2015 at 4:12 AM, Adam Inglis <21pointy at tpg.com.au> wrote:
> I'm looking at installing a midi to trigger interface in my CR-8000, but I
> want to retain the internal trigger function. I need a way of isolating the
> two trigger sources from each other.
> The internal trigger system is from the CPU, via some pull-up resistors and
> a buffer, giving negative-going triggers from 5 - 0 volts, seen in this pic
> here
> http://www.adambaby.com/images/tech%20pics/CR8000/CR8k_CPUtrig.png
> These triggers go to the various analogue voice circuits, here's a couple of
> examples, bass drum and hand clap
> http://www.adambaby.com/images/tech%20pics/CR8000/CR8k_BDtrig.png
> http://www.adambaby.com/images/tech%20pics/CR8000/CR8k_claptrig.png
> I tried duplicating the input capacitor seen at the trigger entry in these
> voice circuits, for each trigger source, however this attenuated the  pulse
> too much resulting in a different voicing (proving that these circuits can
> be "velocity" or voltage sensitive).
> Elby Designs, who make the MIDI2SDS16 interface that I'm testing, say that
> in general you can't have both connected at once.
> Any thoughts?
> cheers
> Adam
> (BTW, Roman asked re a previous post whether there was any change of voicing
> with pulse width variation. In the first pic you can see they quote a huge
> range of variation as the width varies with the tempo, from 4 - 70
> milliseconds. So I guess the pulse width can't be critical. I haven't tested
> below 4 ms though.)
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