MOTM

Just my personal opinion - I think you guys are nutz<g>! The UEG is 
not designed or optimized for sequencer operation, it just includes a 
bonus pseudo-sequencer mode. I'd recommend either waiting for the 
MOTM sequencer, or building your own true sequencer if you can't 
wait. There are dozens of designs floating around that will clock 
faster, and allow you to get the trigger and gate output options and 
stage selection flexibility that you want. My point is that the 
amount of work you'd have to put into the UEG to turn it into a 
sequencer, could be spent to make an actual one. Hell, use my 
SuperMoe schemos if you like (published on my site).

Look at your UEG carefully. Notice that you will have to completely 
disassemble it to get to the pcb, because so many of the controls are 
mounted directly to it. Remember that it is more static sensitive 
than a typical all-analog MOTM circuit. You risk ruining a fine (and 
expensive!) module.

Not trying to be a wet blanket - just pointing out that you should 
pick your DIY battles carefully, and weigh the risks. I would be too 
afraid of screwing mine up, for not enough gain to satisfy me. You 
will have to make that evaluation yourself, of course.

Remind me to tell the sad tale sometime of my "portable B-3" project.

Moe

--- In motm@y..., mark@i... wrote:
> At 5:26 PM -0500 03/08/01, Tentochi wrote:
> >
> >I like this idea!
> 
> That's why I mentioned it :)
> 
> >The easiest way to get this function is to reprogram the chip.
> 
> Yes, that would be the most elegant method.
> 
> Another way which might be possible is to tap the trigger off of the
> existing PCB (which would likely require a daughter board with at 
least a
> voltage follower).
> 
> A third way would be to build an edge detecting daughter board 
connected to
> the CV out of the UEG.  It could be mummified in electrical tape 
and stuck
> with double-sided tape somewhere.
> 
> The first two options require help from Encore.  The third option 
does not.
> If this seems somehow disrespectful, disloyal, unappreciative, or 
immoral,
> to any of you, just try thinking of this as merely some guy trying 
to
> differentiate a stepped function in his spare time :)
> 
> Since the dawn of man, I'm sure someone before us wanted to know 
whenever
> the voltage of a signal jumped up or down.  So I'm thinking a 
circuit that
> does this is already out there.  However, I'm not an EE, and all of 
my
> "cookbooks" are about food.
> 
> Yet, I do have a copy of Horowitz & Hill.  It just showed up one 
day in the
> back yard.  Using stone tools and coconut husks, I pieced together 
the
> following circuit in my mind (please note that my primitive mind is 
one of
> the worst places one could keep a circuit!):
> 
> Take the CV output of the UEG, run it through a voltage follower 
(as not to
> draw too much current), to a differentiator.  Figure 4.51 on page 
224 looks
> like a cap (C) going into the inverting input of an op-amp, with a 
resistor
> (R) going from the op-amp's output to the inverting input, and the
> non-inverting input going to ground, such that:
> 
> Vout = -RC dVin/dt
> 
> Since this looks like calculus I started jumping up and down "Oooh 
oook
> oook! eee eek!!" :)
> 
> Then it says this circuit generally has "problems with noise and
> instabilities at high frequencies because of the op-amp's high gain 
and
> internal phase shifts".  It shows a new circuit, with high-frequency
> rolloff, in Figure 4.52.  Yet it doesn't give a formula in which to
> calculate the component values.  Stupid aliens!!  So I started 
hollering
> and flinging poop at the monolith :)
> 
> Luckily he monolith ignored me, but I knew that even if I could get 
the
> differentiator to work, I would end up with both negative and 
positive
> voltages.  So after this differentiatior, I would need an "absolute 
value
> circuit" or "active full wave rectifier", I found two on page 222 
and
> started beating my chest :)
> 
> After that, I need to get this positive voltage up to approximately 
5
> volts, with enough current available to be used as a trigger.  Is 
there a
> comparator circuit that anyone would like to recommend??  I'm 
thinking a
> LM339 with a pullup resistor connected to 5 volts would work.
> 
> Do they make comparators that will give a positive output 
regardless of the
> polarity of the input voltage??  The table in Horowitz & Hill (pp. 
584-585)
> leads me to believe that an LM311 can, which would eliminate the 
need for
> an absolute value circuit.
> 
> Does all of this monkey business make sense??  Does anyone know how 
to get
> the circuit on in Figure 4.52 so that it will work??
> 
> 
> >Tony has stated several times that most DIYers don't have the
> >equipment to do this.
> 
> I certainly don't!!
> 
> >I haven't programmed any EPROMs for 15 years, so I am
> >not up-to-date in this area and what geeks like us may have sitting
> >around at home...
> >
> >It looks like all of the incoming data is available from all of the
> >switches and you can program the output of each of the
> >jacks--in particular, the TRIG OUT jack.  You can check for LOOP 
ONLY mode.
> >When in this mode, you could use one of the settings on the unused
> >STEP/TRIG LOOP/RELEASE switch to turn on the "trigger out at the
> >beginning of each step" mode.  The location to check for this 
should be
> >very obvious is the source code.  And it should take too many 
extra lines
> >of code to add:
> >
> >At the beginning of each step--
> >
> >	Check for LOOP ONLY mode.
> >
> >	Check for TRIG mode.
> >
> >	Send trigger pulse to TRIG OUT.
> >
> >If anyone can read and burn these chips, I will be glad to help 
disect the
> >code.
> 
> Thanks :)  Does anyone know how to read and burn these chips??  
Regardless,
> building an edge detector might be easier than trying to re-write 
the code,
> which could introduce a bug.  Also, an edge detector circuit might 
be
> useful with other things besides the UEG.