CMOS 40106 'Sync' Effect

Today we're going to take what we've built in the last 2 video and extend it a bit to make it a bit more interesting tonally, by hooking one of our unused oscillators from the CD40106 chip up into another one. We're going to use what we know about oscillators along with some knew stuff about diodes!
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Thanks for watching!

[@arenotdiy7280]

"If the thing blows up, you resistor wasn't big enough" These are the things you must learn the hard way

[@TheAudioPhool]

Right?!

[@michaelhoste_]

I'm glad you finally explained the function of the diode here - Ive seen this circuit elsewhere but the diode was a mystery. Basically while/whenever the first osc is positive, the second one can operate normally (make a sound), Conversely, when the first is zero (or more negative), the second is muted because it's signal is diverted back through the diode. So it's actually the conduction of the diode that 'blocks' the second osc! Got it!! At higher frequencies both oscs contribute a 'sound' because the on > off > on > off rate of the first osc creates an audible tone, made up of little bits of the second oscs tone. [On a side note, you can tailor the freq range of the osc by using a 'small enough capacitor' for the high end and a 'large enough resistor' for the low end. A 1Meg pot and a teensy cap (much less than 1uF) gives you the entire audible range down to a few hertz.]

[@DECIMA1]

Such great videos, very informative! Keep it going bud!

[@TheAudioPhool]

Thanks so much! :)

[@ahdziz666]

Im digging all these videos a lot. I have to mention that the definition of a "cylcle" of the ramp wave at the beginning of the video was actually two cycles of the ramp for some reason so it's double the frequency. That wave would trigger a hard sync twice in what you have marked as one cycle.

[@gerryjamesedwards1227]

You can change things up even more by adding a couple more diodes in the feedback path of the first oscillator, feeding each end of another smaller pot with the wiper going to the existing pot. Changing the new pot will alter the hi-low periods of the oscillator, effectively giving you PWM control. The distinctive sound is due to the overtones. You can find some very talented folks on YT who can do overtone singing, and the effect is very similar. Think of the Mongolian throat singing, that does the same thing.

[@jackevans2386]

0:58 One period from 'here to here' is actually 2 periods.

[@twobob]

This deserves more views

[@LockStoppageSandwich]

Love it and have subscribes………..can you show us how to build multiple oscillators with this chip ?

[@treeski3410]

To the viewer - this one is a little rough but if you hang in there, it becomes clear. Thanks AP.

[@davidrysdam902]

Fun series. This video is confusing me though. I guess you are saying the left osc is the "audio" one and the right is the "effect" one. If I imagine singing a tone vs brrrrr my lips while singing a tone, that's the difference. Except my lips need to be going at a higher frequency than my tone. Kind of the opposite of an LFO. In the demo portion, you are adjusting "the resistor" (I assume on the right osc) to modify the effect. At some points, the oscope is showing the same thing you drew--that the effect signal disappears when the audio signal is low. I understand why that happens. At other points the oscope is showing that the effect signal continues even when the audio signal is low. How is that possible? The right osc would only be able to charge up to a max of .7v.

[@davidrysdam902]

Later: I built this and my left/right understanding was correct. To anyone else reading this: The resistor he ignores in the schematic is kind of important. 1k didn't really work for me. 10k works over a small range. In the video, you can see he's using 100k, which turns out to work really well.

[@TomLeg]

Why are you showing two cycles as the frequency? Should be one.