problem getting gates AND CV from 4017

widdly · Posted: Mon Apr 07, 2008 10:59 pm Post subject:

Actually you could vary the clock signals duty cycle to get a "swing" parameter.

richardc64 · Posted: Tue Apr 08, 2008 6:08 am Post subject:

widdly · Posted: Tue Apr 08, 2008 7:48 am Post subject:

The clock is inverted before the 2nd AND gate so only one AND gate can be open at any time. As long as the one-shots are shorter than the clock duty cycle it will be fine as it is.

Seperate pots instead of the dual-ganged would work to.

Once you chain two 4017's you need to add more logic for the reset and carry anyway.

loss1234 · Posted: Tue Apr 08, 2008 8:01 am Post subject:

how would you change the duty cycle to get swing??

richardc64 · Posted: Tue Apr 08, 2008 8:06 am Post subject:

loss1234 · Posted: Tue Apr 08, 2008 9:30 am Post subject:

OK
are the diodes on each gate out (post switch) important? in other words, on foniks schematic, the diodes come after each switch. the way i wired it, i took a diode out of each step, into the switch, then i chained all the switches together and put that into one half of a diode AND> with the other half of the diode AND being the cd40106 inverter being fed from the trigger clock to change the gate length...also, is the cd40106 the right kind of inverter to use for the gate length changer??

thanks

richardc64 · Posted: Tue Apr 08, 2008 11:00 am Post subject:

loss1234 · Posted: Tue Apr 08, 2008 12:26 pm Post subject:

maybe the diodes are what are messing up my gates then!! i have to use an AND chip, not a NAND right? or wrong?

let me see if i have one of those....i already have the 40106 wired up

thanks

widdly · Posted: Tue Apr 08, 2008 6:40 pm Post subject:

richardc64 · Posted: Wed Apr 09, 2008 3:02 pm Post subject:

loss1234 · Posted: Wed Apr 09, 2008 3:36 pm Post subject:

richard64-

i was going to ask, i had some problems with the inverters. after removing the offensive diode AND circuit (which was messing up my gates btw) I tried your FIRST schematic and it didnt work. maybe it was too large a pot or cap value ( i tried a 103 cap between the first inverter and second, and a 100k pot 10 1k to volts) no luck. it works better with just the gate outs straight from the diodes of each step...

so i want to try the new verison BUT should i try a different cap value? (i was anding with a 4081 btw)

thanks

richardc64 · Posted: Wed Apr 09, 2008 6:10 pm Post subject:

widdly · Posted: Wed Apr 09, 2008 7:16 pm Post subject:

loss1234 · Posted: Wed Apr 09, 2008 8:04 pm Post subject:

richard

no, what i meant was it the clock pulse didnt work mixed in at all (to shorten the steps) in the end i ripped out your circuit and just took the outs straight from the steps (with diodes) as i couldnt get the pot/cap combo to do anything

i will take a shot at the new schematic and try a higher cap size though tomorrow

thanks for all the ideas and help

widdly · Posted: Wed Apr 09, 2008 8:27 pm Post subject:

How about adding swing to the CV outputs too. Here's an idea...

You could use two of Rene Shmitz Minimum circuits ( or some other Buchla trough type circuit). http://www.uni-bonn.de/~uzs159/minmax.html

I guess you might need a comparator on the clock signal to ensure it has the same swing as the 4017 outputs. It would be nice to include a one shot one the clock signal for these circuits so that there is an integrated swing control regardless of the clock duty cycle.

I'm not sure about the outputs, it might be an idea to use an op-amp summer.

Oh, and if you built something like Fonik's babyseq, you could add a switch for this too so it does either 2 x 8 or 1x16 with swing.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Funky40 · Posted: Fri May 30, 2008 1:22 pm Post subject:

richardc64 · Posted: Fri May 30, 2008 4:06 pm Post subject:

Funky,

Those are inverters, and any of several ICs can be used: CD4069 or 74C04, or CD40106 or 74C14 Schmitt triggers. They could even be left-over NORs or NANDs with inputs tied together.

But I'm thinking maybe the 4017 clock is too brief or narrow to reliably trigger the one-shot, which is a half monostable and something slightly different is needed: a full monostable, as shown below.

R/C values shown are only suggested. Experiment!

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Funky40 · Posted: Fri May 30, 2008 5:45 pm Post subject:

Thank you very much Richard.
It is not specific for the 4017 .
More important for now is to DIY something like the Q961 from dotcom for my Q960.
http://www.synthesizers.com/q961.html

But i have also a 4017 in work (hmmm, since quite a while... )

whomper · Posted: Fri Feb 12, 2010 3:06 am Post subject:

Hi,

I have tried to use a simple diode AND circuit as per the attached image but could not get a pulse signal at the output. Used 1N4148, +15V and 1M for the resistor.

Must I go for a CMOS solution, like the 4081?

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fonik · Posted: Fri Feb 12, 2010 3:38 am Post subject:

i don't think it will work. as i understand it the idea is to have the current flowing from +V thru the diode(s). as soon as there is a HI at A & B the current would have to flow to Z. but how could current flow from +V thru the diode(s) when there is no sink at the other side?
am i right?

RF · Posted: Fri Feb 12, 2010 7:36 am Post subject:

Here's a not-quite perfect, quick, dirty, cheap hack to get sequential-step triggers from a Baby 10 type sequencer.

(Have I under-sold it enough yet?)

Chain the Gate Switch Diodes from the Even steps together, Chain the Diodes from the Odd steps together, run them each to a Gate to Trigger converter. Sum the outputs of the two Gate to Trigger converters.

It'll work fine unless you set the sequencer to an odd number of steps - then the last step will become a long gate if step one and the last step's gate switch are both on.

Did I mention it's not very elegant?

bruce

fonik · Posted: Fri Feb 12, 2010 8:04 am Post subject:

for a CMOS solution refer to my VCPS8.