What does this mean?
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Come on now … I know a clever guy like you can work that out … 
I have to leave a little headscratching surely? 
Mmm 3 vertical dots left are spdt switch and 3 vertical dots right are vol pot ( obviously😁)
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Mfos dual A/R generator.
Built just the one …flawless operation.
Remember to inverse orientate that tl074 !!!
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If it were obvious, I wouldn’t have asked.
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Why, Indeed. Obviously 
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MFOS “oldie but goodie” State variable filter.
One of my earlier builds , must have been satisfied with the results cos I built more
Please have a look here for more info and assistance
Schematic
Now then … one thing to add… cv control will probably need to be attenuated .
the cv input is easily overdriven and is exceptionally loud when done so therefor you will need to attenuate the cv inputs suited to your needs. You have been warned. I think I put larger resistor Maybe even 470k on the cv control . Take heed . Its a ray wilson work in progress really.
However , I have three Of these and all modes have a good Full response throughout the cutoff range I will attest .
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Hello!
I made a Eurorack-friendly version of the Distortion+. It sounds good.
I removed the input offset voltage as it is no longer needed.
It uses dual opamp instead of single as everybody has those somewhere.
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Cool ! where come from this schematic please ?
Have you some sounds ?
thx 
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I used the MXR Distrotion+ schematic from Electrosmash.
I might record some sounds later. It sounds a bit like overdriven MS-20 filter as it is simply hard clipping the signal.
Please be clear about the polarity of the power connector. The red pins can both signify +12V (as it does), or the red strip on the power cable (-12V). Thanks!
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This one ?
link here :
https://www.electrosmash.com/mxr-distortion-plus-analysis
btw you don’t adapted the impedance (input & output) of a guitar pedal for a synth level ?
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Note that even with five caps in such a small circuit, none of them are bypass caps…
It sounds good without impedance adjustments.
The red is +12V and blue is -12V.
Bypass caps always be added later.
100 nF bypass caps should go close to the IC, which is difficult if they’re not designed in.
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Maybe add the credit of the schem on your layout ?
For the impedance i think that is not a sound’s question, but more to protect your circuit of the hight synth level
For info you can look at this kind of module
or here @Jos used the same schematic (stomp box adapter) to his module
but if it work for you …
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I made a quick demo with some distortion knob twisting action:
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I don’t think anything here is going to be damaged by a synth level signal, especially with a ±12 V powered TL07x replacing the LM741 (∆V = 24 V vs 9 V).
If the results are what you want it doesn’t matter. But with the distortion pot in the middle, basically you have a 3x amplifier and the op amp will clip on any signal larger than about 4Vpp. So not with a guitar signal but probably yes with synth. But for a distortion module maybe you don’t care, especially with the following diode stage.
As for the output, especially with germanium diodes it will be very low (~0.6 Vpp), and they’ll more severely distort a signal from a synth than one from a guitar.
Anyway, if it works for you it works, but I’d think attenuating the input and boosting the output (and/or using silicon diodes and/or more diodes in series) would be worth looking at.
The 1M pot and feedback resistor look odd to me. Guitar pedals typically have 1M input impedance but these aren’t on the input side. Usually in synth circuits you see ~100k on an inverting input stage and often ~10k on other stages. Larger resistances tend to make for more noise. Whoever designed this as a guitar pedal presumably had some reason, but I don’t know what it was or if it would apply for a synth version.
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thank you for all these precise explanations
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good choice for the demo. Sounds great!
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Thanks for posting this Dual VCA layout. I just built it out.
To add attenuators on the outputs could I add 10k linear pots (leg 2) to the output lines?
Planning to do a similar thing with the CV inputs. Will also add an LED on the cv inputs. Do you think I need a 1k resistor to protect them?
Thanks again for the easy to follow layout, I’m building two for a 12HP Quad VCA module 
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