Sequencer Gating question

[Ric Miller]

'k kids.  I've got an odd question:  (Background first).  I finished the
prototype for a new sequencer design from myself, on Monday evening.  2
x 8 step sequencers that each have, or are capable of:
- Looping ability between 3 - 8 steps
- Main Clock (Internal or External) divisions of 1, 2, 3, 4, 6 and 8
Clocks before doing a step
- A pitch knob for each step (about 4 octaves)
- A pitch transpose knob (as well on each step) with an On/Off switch on
each step
- An LED for each step

In the original design for this sequencer (Stompin' Tom the 3rd) I had
planned on having the Gate signal for each sequencer, be turned on, if
the Pitch on the given step that the sequencer line was on, was OVER 1V
DC.
On the CV Output of each of the 2 sequencers, I'm summing all of the
Pitch and Transpose pots, through 100K resistors, into an Inverting
Summer, with a 51K feedback resistor (to cut the total voltage of Pitch
and Transpose on each step by half) and feeding this into another
Inverter through a 100K resistor, with another 51K feedback resistor.
(This is then the CV output, of each sequencer.  And yes, every Pitch
and CV output (before their pots) are fed through their own diodes, so
that there isn't any other path for either of the voltages to discharge
through, except for the output.)
This is then the Output CV for each sequencer line.
This output is also fed into a comparator whose Negative Input is fed by
a pair of resistors set up as a voltage divider, from the +15V supply.
(150K from + and 10K to ground)  This leaves a Threshold of +0.93 volts.

The INTENTION here, was to ONLY turn the Output of the Comparator to
HIGH (+15V) if the CV Output voltage were above +0.93V.
BUT ..... doing this, caused one of the WEIRDEST bugs that I've seen
yet, in anything that I've built or designed. :O
(This was tested when I'd only had 1 of the sequencers built.)
The results were Gates happening SOMETIMES, depending on the Pitch and
Transpose settings of each step.  The Gate would ONLY occur, when the
pots were in a very small range around the 1/4 of the turn, of the pot.
Turning the pot below this point, or past it, would cause the Gate to
NOT occur on that step.
I never WAS able to get all 8 steps to output a Gate, either.  The most,
if I remember correctly, out of all 8 steps, was 4 of them.
I'm completely unable to see (with my little bit of electronics
experience) WHY this would happen.
?????  I hope that SOMEONE can help with this.  :O
My other idea that I've thought of trying in this regard, is running the
CV Output, through 2 x 1N4148 diodes, to achieve a voltage drop of about
1.2V, and then feeding this into a Comparator, whose Negative input, is
fed Ground.
The output of the Comparator as well, would be passed through another
1N4148, to only allow + voltage Gates to occur.  (Something that I DID
forget, on the V1.00 of this sequencer PCB.)
Using this method, I STILL don't see any way, that this should affect
whether there is a Gate or not, on each step.

I'd REALLY like to get this function working, as this would add the per
step function of Gate On, or Off (for Rests).

On top of that ..... I'm wondering if anyone has ever seen a knob based
sequencer that was capable of having a switchable On/Off transposition
setting, on each step.  ???  The only knob based sequencers that I've
ever owned/used were the Korg SQ-10 and EML 400/416.  Neither of these
had this function.  I'm wondering if anyone knows of any other knob
based sequencer that did?  (This transposition function is easily
possible on sequencers with rotarys switch Pitch controls, or Quantized
slider/pot controls (like the EML 400/416.))  This function, is
absolutely WONDERFUL for doing transpositions on the fly, like Tangerine
Dream 'tunes' from their late 1970's albums.  (One of the main reasons
WHY I designed and built this sequencer.  I've wanted one like that ever
since first hearing their tunes, 15 years ago.  :) )

Thankyou grandly for ANY help in this regard!  :O  As soon, as I get the
work done, there'll be photos, a schematic and wave files, of this
sequencer up on my homepage. :)

Ric

A.R.F. is dead - May 22nd, 1997
http://www.pangea.ca/~rmiller