DIY Metallic Percussion Synth

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Today we're going to explore one of the weird and wonderful ways we can take CMOS logic gates and use them to do some unexpected stuff. This uses an XOR gate as a 'frequency mixer' to make us what is essentially a really simple FM synthesizer!
Use this to make analog cymbals, hats, cowbells, bells, gongs.. whatever you want!
Schematic! - drive.google.com/file/d/1Sr75...
Folder of other Schematics: drive.google.com/drive/folder...

[@ke9tv]

One interesting effect that you may not have tried is feeding frequencies in the ratio of 5:2 (a major tenth on the Pythagorean scale) into a "dirty" ring modulator that will have feedthrough of the inputs as well as the modulation products. You get a whole stack of harmonically and subharmonically related tones because the difference tone is 3:2, the sum is 7:2, there are third order products at 1:2, 9:2, 4:1, and 6:1, and so on. The emphasis on the half harmonics (fundamental, 3/2, 5/2, 7/2) gives an open sound that can, with a little flitering, give kind of a brass-instrument tone.

[@CatFish107]

Whoa hohohoho! Ooooh yeah, will absolutelutly try feeding square waves into xor gates in vcv rack now. Great patch idea. Thanks

[@jj74qformerlyjailbreak3]

You uploaded the sch for the mixers “inverting and Non-inverting” on Google Drive at the same time and day I found my mother had died in her sleep. It was a sad thanksgiving. Finding these schematic’s assures me I’m on the right track recovering from that day. Thanks for all your hard work you give the world. Your an awesome teacher. God Bless

[@TheAudioPhool]

That is absolutely awful. I'm glad I could help in some small way. So sorry for your loss :(

[@davidrysdam902]

When I followed the schematic for this, I had two problems. The first was that the output of the transistor was all negative voltage, which made the VCA not work. I fixed this by putting a big cap inline with the output. That centered me on 0 at least. I also had a LOT of high frequency noise that I couldn't track down. The noise existed somewhat at the output of every XOR and seemed to just add up through the circuit. I fixed this by adding a .33uF to ground between this circuit and the VCA to be a low-pass filter, but set very high.

[@TheAudioPhool]

Hi David! I might have to revisit this schematic. Sounds like I might have made a mistake somewhere. Thanks for watching and thanks for the feedback :)

[@TheAudioPhool]

With these CMOS circuits decoupling can be fairly important especially when you're using the 40106 which I think those one uses a lot of from memory. Could explain the HF noise. Will have a look this weekend!

[@TommyBoy7Heads]

Such a cool channel. Thanks man. Also glad you left the almost spilled drink in. Keep it real.

[@baddriddimworkshop]

i remember seeing a "gong" circuit on one of my books (you know those old 80's book full of all the same audio circuit schematics, i'm shure you must of seen it somewhere), never tryed it though. you gave me motivation to learn more about logic chips(i'm thinking to add push on/push off buttons to each gate track of a sequencer to reduce buttons for beat programing, and then i thought this i/o info per step could be stacked in somekind of memory, with a battery it might be very simple to do). for those types of sounds, FM is the best way, but a filter behind that circuit you designed here could be usefull to getthings to sound like different metal drums. an ar could be cool too... love your channel mate

[@TheAudioPhool]

This is amazing! There are loads of really clever and interesting things you can do with logic circuits. I'm actually planning to come back around to my analog sequencer that i started a few videos back, and have plans to try something not dissimilar from what you're describing so keep an eye out :) Thanks for watching and i really appreciate the thoughtful comments.

[@baddriddimworkshop]

@@TheAudioPhool in fact i just made a little seq for my modular fx system (i design and build things for the dub scene), but i'm thinking of making a "matrix" sequencer (8x8 with 4017) and that would have another sets of sequencers with gate output at each step so you can sequence sequences to make a full song. oh damn i love this shit haha! and i have spent all my days on this since 5 years now.....

[@npx_riff_lift-g]

an amazing lesson on sonic theory. subbed for sure!

[@tomwawer5714]

Instant sub very interesting sound out of mundane xor gate yay

[@stephenmaughan]

Love the sound of that. I need to make it once I get my head around how to do it.

[@floretionguru2977]

You are a great teacher. I have a back-of-the-envelope schematic of how to do quaternion multiplication with (N)XOR gates and am currently working through DIY synth exercises as a hobby on the side to prepare myself for the bigger project. Great to see them in action here.

[@TheAudioPhool]

XOR (or XNOR!) gates are every EE's favourite toy. Thanks for watching :)

[@stuartchapman5171]

Love this. I have a stack of logic chips and build a few basic drone box's. I use them to create complex shifting drones with stacks of pedals. Looking forward to seeing some more of your vids.

[@jakobhalskov]

Super cool and well explained! I am working on some TR-808 circuits and will soon be sharing a video on that. Looking forward to see more from you :)

[@CodyRedmond]

This is awesome. So happy to discover this! Subbed.

[@CodyRedmond]

finally getting my money's worth with my intellijel shapeshifter 😂

[@plop-4269]

I was looking for a simple VCA for a hi-hats circuits and found your BJT VCA's video, the i take a look at the other videos and found this one =) It's what i've been doing all day Your videos are amazing btw !

[@ZenZoba]

By far this is my favorite channel . Thank you so much for this channel. Very well laid out and VERY informative.

[@TheAudioPhool]

By far this is my favourite comment! Thanks you 😊

[@samlofthus7661]

Cool videos man. Keep it up 🤙🤙

[@TheAudioPhool]

Thanks mate!!

[@MarcDupuis50400]

Very interesting stuff!

[@mattmeckel99]

Thanks!

[@zetaconvex1987]

Interesting channel. Glad I found it. I'm a bit of a duffer at these things, so you're quite a bit above my level of understanding. It's interesting when you mentioned XOR gates. I was toying around with trying to make my tones sound richer, and I came up with the idea of sort of binaural beats, mixed using OR. I was quite pleased with the results. It turns out that my idea wasn't as daft as I first thought. I had wondered, though, if it might have been easier just to mix the outputs from two separate pins.

[@MattDiamondMDE]

Great vids! Thanks man

[@jamesgilmore2389]

Great video. Thanks.

[@TheAudioPhool]

Thanks for watching!

[@pete3897]

So the take-home I got from the last 2 minutes of this video is that you would like me to go away :)

[@angelofeffektd6462]

The church like Sound is created by having 2 or more frequencies nearly at the Same Note...I think

[@cj-er4xr]

thanks!

[@foobeaglebar]

420, nice

[@TheAudioPhool]

heh

[@skriptico]

Bello!

[@toreeriksson6117]

Nice! But is it okay to short circuit the input and output of a Schmitt trigger (if a pot. is set to 0 ohms)? Also, can I use a 74LS14 and 74LS86 instead of CMOS technology?

[@TheAudioPhool]

Yes it is ok - there is some resistance inside the chip that should limit the output current. The technology (CMOS vs TTL) shouldn't matter, i just find CMOS to be a little hardier and can take a bit more abuse! Particularly when it comes to supply voltages. Have fun!

[@toreeriksson6117]

@@TheAudioPhool Thanks for the quick reply. The reason I prefer TTL is that I have a pretty large drawer full of them. :) Also, I think I heard a long long time ago that TTL is able to take more ESD abuse, at least the really old ones. But I could be wrong.

[@TheAudioPhool]

@@toreeriksson6117 I always think the best parts to use are the ones you already have!

[@Bob.isnotmyname]

Lol

[@martingerken7094]

Poor little scope screen..