Sequencer success!

[Hairy Harry]

Hi Mitch.

Yes... you could put a resistor in series with the high side of each
pot...

~or~

CMOS can run on voltages from about 3 to 18 (MAX) volts... if you
wanted less range you could slap a 5V regulator on the supply comming
into the PCB.  Or any other voltage you wanted between 3 and probably
12V (assuming you use a 15 volt supply...).

H^) harry


>From: Mitchell Hudson <mitch at sirius.com>
>To: EFM Synth DIY <efm at xavax.com>, Synth DIY <synth-diy at node12b53.a2000.nl>
>Subject: Sequencer success!
>Date: Fri, 13 Oct 2000 04:37:07 -0700
>
>     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
>

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