[sdiy] tr 606 heavy modularization, pictures and questions (4:37 am)

[Robin Whittle]

Anthony Bisset wrote:

> Would it be simpler to hijack the post logic instrument trigger
> pulse's themselves rather than worry about summing trig and accent
> together?

Yes.  For the TR-606 and TR-808 at each drum circuit there is a point
with a 1ms wide voltage pulse, normally 5 volts but between 5 and 14.4
or whatever for an accented note.

This is the only sane way to switch and process drum triggers - and then
you can go to lower volumes and intensities, with lower voltages.  Each
drum circuit has its own voltage at which there is little or no sound.
In the TR-808 the Handclap does not alter its sound much according to
the trigger intensity.

For instance in the TR-606 Bass Drum circuit, the signal at the
collector of Q15 is the point to do the surgery.  External triggers can
be done at this point by putting a diode between the collector and the
top end of R63. (Cathode to R63.)  A second diode with its collector
also to the top of R63 can be used to logically OR in external trigger
signals.  These should also be 1 millisecond or so long and between 5
and 15 volts.  These diodes introduce 0.6 volts of drop, so it is best
to boost the voltage of the "Normal" trigger voltage by 0.6 volts or so.
    This is a little trickier . . .

  - Robin   http://www.firstpr.com.au/rwi/dfish/