Simple Twin-T Kick Drum

tune pot is good (from diode) but with 220 not 50K resitor

i put still my build in this thread

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Thanks. What a great learning.
I understand the need to place the 100nF cap near the IC pin. The video also explained why to have multiple different bypass caps to better deal with impedance.
But why does it use the same 100nF cap?
And why is it placed at the other end near the PSU?

After breadboarding the @Krakenpine ‘s version didn’t work very well for me i can’t figured why :confused: maybe it’s my cheap aliexp’ OP-Amp i modified the trigger input to match with the one from the original Kassutronic workshop , and it work way better I did a bit of kikad to add the led driver from @Dud website and the attack switch a potpourri of everybody’s ideas :smiley:
Here is the schematic, i double-checked twice but error can remain.

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On your new schematic, you change some value
2 x 500K to 2 x 470K
2 X 50K to 51K
2.2K in 3K

Not some really very important difference, but maybe it’s better to use the exact value for the best result.

This module has been tested by several people (at least 2 :slightly_smiling_face: ) and works fine like this. Changing a few values ​​can sometimes / maybe / a lot / never, cause problems.

For Trigger, the initial schem work well too, maybe your invert trigger problem come from your external machine.

Have you tested with a mulimeter the trigger signal coming out of your trigger machine ? what do you use to trigger this module ?

and on your schem you forget the 1K resistor on the OUTPUT.

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Maybe. There’s a topic about that.

I’ve bought chips off AliExpress but only ones I don’t have a critical need for and can easily test to see if they do what I need them to. Op amps I get from Tayda, Digi-key, or Mouser. The price is higher but they’re going to be genuine.

Did you use IC sockets? If so then the good news is, swapping out for a more reputably sourced op amp will be easy.

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It’s after reading this thread that I thought it might come from my OP-Amp :slight_smile: I use sockets as much as I can because you never know.

On your new schematic, you change some value
2 x 500K to 2 x 470K
2 X 50K to 51K
2.2K in 3K

Yep i swap them for the nearest value i have (i try on breadboard and it’s working nicely)

For Trigger, the initial schem work well too, maybe your invert trigger problem come from your external machine.

I try different things, with 9v battery, with an home-made PSU and some different voltage divider, and with the +12 rail from the module, i’m currently working on a gate sequencer but still not finnish so i can’t try with it.
They all do the same and trigger the sound when the signal go from HIGH to LOW on a reverse voltage.

and on your schem you forget the 1K resistor on the OUTPUT.

Wow, thank you i’m gonna edit my post with the new schem :slight_smile:

Well i cannot edit the previous post, the new schematic is here, thank’s again :slight_smile:

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@Dud which name do you prefer SoundBender, Dud or what ?
I’m gonna share the gerber here when i know it’s working, i will order PCB in few week i have to re-check everything again :slight_smile:

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it is used as a noise transistor correct yes

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thx for asking but you can leave my name, you make all this from the original schematic and add some change :wink:

Looks dope, would also be nice if you could share the whole KiCad project, not just the gerbers, so we can make a “Kosmo”-style version. We don’t have a Kosmo drum yet, AFAIK.

warning the original schem work fine with my kosmo modular (trigger by an LFO, gate, beatstep …), but in his mod version he add a circuit to reverse the trigger signal input (not good for you i think :slight_smile: )

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@Dud Thanks for sharing your stripboard layout. Today I finished building it. I wasn’t a fan of stripboard layouts at first, but it was a really relaxing experience, so I think I will be doing this some more :grinning:.

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yes i like it too ! happy that’s work :slight_smile:

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The proper name is “Rally English.” Classic clip from that genre:

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Now there are more and more interesting and verified modules here :slightly_smiling_face:

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Hi, I received the PCBs for the drum-kick, all works well :slight_smile: The trigger is not inverted, you need at least 5v to start it.
I made a gitHub repo with all the kicad project and the gerber folder. I used homemade fingerprints for easy soldering.

Here is the link : GitHub - Pl0p/Drum_K: Analogue drum kick

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I started thinking of how this could be make more snare-y. Having a noise source and getting a release envelope from the trigger and using that to control the noise with a extremely dirty vca (consisting mostly of one fet and a diode) and then summing that noise to the oscillator tone and letting the distortion circuit to glue them together sounds promising. Let’s see how this goes.

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i don’t know if that can help you, in your description, there are similarities with this build

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