White noise hats

As I’m slowly rounding my way to filling out a basic rhythm section in my synth, I’m looking for some hats/cymbal sound created with white noise to match my twin t kick and snare vibe.

I’ve seen here on the forums various bits and pieces, but haven’t really found that super sharp and snappy hat sound I’m craving. I know I could:

  • start with white noice generation
  • roll up a high pass filter so we mainly get that sizzle
  • use envelope generator
  • use VCA
  • trigger the envelope generator
  • tune the path to get that snap

but this seems like lots of modules for what feels like it could be a super basic hats module in the same vibe as the twin t kick and snares I’ve seen here.

Does anyone have something like this? Ideally with white noise generated by a 2n3904 with a leg missing and the ability to not have a rolling off decay, but more a snappy snap snap end point if I want it, and some filtering so it’s toppy.

I’ve done some netrunning and mainly I see super huge builds with lots of specialist ICs that I feel could be done mainly with discrete components.

edit: I seem to be a search fool - sometimes not seeing all the results. For some reason I find the search function a little odd here on the forum, but anyway:

I found of course @Dud has this on his great site: 22. SYNTHÉTISEUR MODULAIRE DIY – HIT | SOUND BENDER 36

But @Dud in your video, it sounds like the hats are a little filtered down, like they’re missing the top end sizzle - is that the case, or just the way it was recorded?

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Yes already in my demo video, the sound is not very good (old camera :slight_smile: ), maybe rather listen in my “modular track” playlist (not in the 1st part it’s a bit old now) for a better sound recording.
But otherwise it is a very very simple module and it would surely require some modifications to be able to also adjust the frequency, but it do the job

There’s also the CMOS noise bell, very versatile

and maybe some idea here too

I am not sure if it fits your brief but the Barton Analog Drum module might work. I have built four of them into one module.



With 5 knobs for each? Sounds like a big module!


It is fairly big. I think it is worth it though. 300 x 200

So it’s a multi-use drum module, meant for kick/toms/weird sound whatever right? I’m at the point where I need to think about toms and man I always struggle to find the right tom sound.

Do you have any examples of your modules in action? I had a listen to the source website, but it’s not so useful


If you go to about 3:15 in first the video I start mashing the settings. There is only one module in the video. The second video shoes the four modules in one panel.


For Tom/Bongo … @saint_et_moudulard have done this one


This is nice! Thanks @Dud


Thanks - looks interesting, but not sure I enjoy the sound so much - I love a bit more rounded bump if that makes sense?


Analog toms…ehhh haha. I can squeeze a good kick out things but it’s fiddly. Toms always sound kinda cheesy to me. But maybe I just don’t have proper gear for it. I built the Thomas Henry bd+ and have drumBs.

I almost always end up using my TR-8s/samples.

Analog hats tho…the best


yep I understand what you mean, I’ve done another one since then and I’m looking for how to make the bongo sound with a lowpass gate…

maybe you can try the CGS18 Drum Simulator by Ken Stone

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drumBs is good too !! :slight_smile:

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@Dud I’ve constructed your “HIT” module from the source schematic (as well as a stripboard layout here:)

What I noticed straight away is that I’m getting SUPER low output. Reading around the net I’ve found others also only getting a slight tick from it, and it seems this schematic actually needs to be driven with a 12V gate source, and not much luck below that (some managed with 9V).

I was wondering how you managed with yours? Did you modify any of it to make it more suitable for 5V+ gate sources in the Eurorack world? Or did you simply amplify the output with an opamp to bring it up? (or perhaps you’re sending triggers @ 12V?)

EDIT: I’ve just put together a little buffer to boost the voltage going from the gate source to this stripboard percussion and though it’s now a little higher in volume output, it’s still a strained little sound rather than what I hear in your video, even gaining it up on the output still isn’t really giving me a gated white noise sound, more a kind of crackling

ANOTHER EDIT: Well it seems like the first 4 x 2N3904 transistors I picked up from the drawer were the same kind of bad: like an LPF was on them, which meant that after the caps filtered the snare part out there wasn’t much more than a crackle left. I continued to swap until I found some that sounded ok. BUUUUUT then I thought “hey why don’t I try a BC547 from that bad batch I found a little while ago with paint on them” and amazingly they give me this super weird crunch that sounds like a bandpass is in the middle making them a little honky. Far more interesting than an imitated snare!

I’ve made a couple more changes to values of resistors around the place and have built a buffered input for them, so I’ll finish it off with a buffered output and rejig the stripboard so that others can use it too. I was initially coming into this one looking for a rarely used sound that might be a bit crap, but have found some really interesting percussive sounds that’ll work with glitchy intros to songs, or fade out fall apart moments where we return to just a voice (aka Thom Yorke style - huge fan).

I’ll either finish this tonight or tomorrow hopefully so keep an eye out


So here’s my little addition to the module above, I’m just using an op amp in non-inverting mode to amp up the 5V input up to saturation or close to it so the signal is hot enough to drive the percussive noise voice well (without enough voltage, you don’t get that hard hitting percussion sound).

Happy to take pointers here, I’ve not really done much from scratch with op-amps, but this has been running all afternoon on a breadboard while I’ve been testing my percussive noise voice. Unfortunately I’d already built the stripboard otherwise I would have redesigned it to incorporate this, I still will in time.

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I forgot where I read it, but you can get louder noise if you add a capacitor to the noise transistor, like the 1uF in the bastl noise square:


They also add an opamp after that to increase the amplitude (gain of around 25).

Maybe you can experiment with that?


Yes the very low output is the most problem, but i use a mixer module to balance the level with my other drums modules and increase it after with my mixer table.

I have no problem with my Beatstep pro to triggering it.

I think we must keep in mind that it is a cheap module (besides, I did not do the “snare”, not good for me)

EDIT : i just see that i write in my blog " + add an op amp" (surely for the output)


for the “crackle sound”, have you tested different values for C1 & C2 ?

Ah this is excellent! It’s night here now so I’ll check it out in the next day or so, already I’m thinking I’ll have an OP amp on the outputs with different gain for each as the hats are quite punchy compared to the snare with the LPF effect going on.

Thanks for that!

Sorry yes it turned out to just be the first 4 transistors I pulled out had the same bad noise almost with no high frequency coming out. I’ll update this layout with what I’ve done now by swapping the snare noise source transistor with a BC547 with a certain hFE value that’s giving me a super interesting crunch snare.

More to do on this! Thanks

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