Sequencer success!

[Mitchell Hudson]

    So the beginners have done it again! Yep they've found the simplest
most basic 8 step sequencer they could find, put it together and it
mostly works! Two IC's, one transistor and three resisters not counting
the front panel components.

    I do not remember where I found this schematic, if anyone recognizes
this one let me know. I put a copy of it here

www.webdevils.com/schematics/SEQ8.jpg

    I put this together on a perfboard from radioshaock and made a front
panel from a two unit frac panel. I left some room on the panel for one
more knob and a couple of extra jacks so I can add a clock at a later
date.

    There are a few things that need improvement. It has one small
problem with the up/down switch. When switched the sequence runs
backwards and stops. Not sure what the problem is, I am assuming of
course that the sequence should not stop but repeat backwards when the
switch is down. everything runs fine in the forward direction.

    The output seems a little high, I am assuming there is a range of +
a small amount of volts up to +15V. Initial tests using the sequencer to
control my VCO, through the v-oct, seem to show that the knobs are only
useful for about half of their range. The rest of the range being too
high or too low depending on the initial pitch of the VCO. Seems what I
really would be looking for would be a range of 0 to +10V? I am thinking
there is probably a way to scale the output down a bit with a resister
maybe. Though for some reason my beginner instincts are telling there
should be an op-amp involved because these things seem to end up in
everything and this circuit doesn't have one, yet.

    I had the idea that if I built a clock with two outs that flip
flopped. I could build a second simple 8 step sequencer and clock each
from one of the outs of the clock and get 16 steps out of the two...

Thanks

--M