Niiiice I’ll have to build yours. Did you just use VCAs for cv control? I’m imagining cool things when used with a sequencer
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It uses analog switches as pseudo VCAs for the square wave outputs of the CD4040.
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Hello Soundbender,
I see that you have added the option of being able to control 3 of the 7 pots with CV using a rotary switch, but only one of the 3 can be selected using the switch.
Is there anything wrong with building all (/8 /4 /2 1 x2 x4 x8) with separate CV inputs (jack socket)?
If nothing speaks against it and it is technically possible, I would just have to connect the respective potentiometers to the outputs of the CD4040, right?
I hope what I write is somewhat understandable, my English is not very good!
This is another approach to a CV version, it has CV inputs for all 7 octaves:
I did it using the Barton PCB and my own auxiliary PCBs but I would think the former could easily be replaced with the above stripboard and the latter could be done as stripboards too if you’re up for making the layout.
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I was just looking at the schematic for the original module and was thinking it would be easy to add a sync input for the 4046. I done quite a bit of experimenting with the 4046 last year and one intersting feature is that pin 5 can be used to sync the internal vco. Not sure what effect it would have in the current application, but I suspect it could be interesting to try.
Thank you analogoutput, I’ve seen your CV version before and I’m also thinking about having the PCB made, I’m a bit undecided which way to go.
A great job you’re doing and thank you for sharing it so generously, I’ve already recreated 2 of your works 
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I can attest that stripboard is possible. I have it half built and it is one projects that is a high priority to get back to. I will admit if I had it to do all over again I would probably get the pcb printed - the pinout of the 4066 really bends my brain for some reason.
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I also like “doolang” this modulation is particularly audible at the high frequencies!
Does anyone else have this problem?
Like “analog output”, I increased the 1K resistor to 6K, but this didn’t make any difference for me.
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I use a modification of the Non Linear Circuits threshold. Instead of 100k over 1k (Barton) or 100k over 10k (NLC), I use 100k over 18k. This gives a threshold of around 1.7 volts, which a saturated transistor plus a diode drop may be able to pull a low on (you with diode logic will appreciate this). And BTW on the Barton trapezoidal LFO, it can have problems cycling because the negative swing of a 'TL07x Opamp is not near as much (absolute sense) as the positive swing, so the thresholds used in the circuit can get it stuck on phase 3. Little changes like these make these otherwise brilliant circuits operate with more of the modules in the wild.
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