# SIDE CHAIN MODULE (Ducking) **URL:** \ **Category:** DIY STUFF\ **Created:** [February 22, 2021, 11:04am UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998 "2021-02-22T11:04:21Z")\ **Posts on this page:** 14\ **Page:** 2
**Author:** ![jackb](https://avatars.discourse-cdn.com/v4/letter/j/65b543/32.png) [@jackb](https://lookmumnocomputer.discourse.group/u/jackb)\ **Post date:** [September 20, 2021, 8:52pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/22 "2021-09-20T20:52:31Z")
Yes! I did make a few minor modifications to get it running with a stompbox 9v DC supply and to accommodate a microphone signal for the sidechain. ---
**Author:** ![konthaar043](https://avatars.discourse-cdn.com/v4/letter/k/a88e57/32.png) [@konthaar043](https://lookmumnocomputer.discourse.group/u/konthaar043)\ **Post date:** [September 20, 2021, 9:05pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/23 "2021-09-20T21:05:54Z")
Very nice pedal 🙂 What did you have to change to make it work with microphone level? ---
**Author:** ![jackb](https://avatars.discourse-cdn.com/v4/letter/j/65b543/32.png) [@jackb](https://lookmumnocomputer.discourse.group/u/jackb)\ **Post date:** [September 20, 2021, 9:12pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/24 "2021-09-20T21:12:33Z")
Thank you! A very minor modification but I had to change the resistor values in the first op-amp stage to boost the signal enough to drive the vactrol - that’s the preset pot in the top left of the second image. I used a rail splitter chip then to split the 9v supply in to +4.5 and -4.5 ---
**Author:** ![konthaar043](https://avatars.discourse-cdn.com/v4/letter/k/a88e57/32.png) [@konthaar043](https://lookmumnocomputer.discourse.group/u/konthaar043)\ **Post date:** [September 20, 2021, 9:35pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/25 "2021-09-20T21:35:54Z")
Yes that makes sense, microphone level would be quite low compared to synth level. Thanks for explaining 🙂 ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [November 7, 2021, 2:10pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/26 "2021-11-07T14:10:52Z")
My finish build ![20 - ducking side chain - sound bender (1)](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/c/9/c9ba0017690ee47ff9b5e609073567b1f1db30da.jpeg) ![20 - ducking side chain - sound bender (2)](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/b/1/b14ac79382b912f561aee24de1f72acb0d0878c3.jpeg) a little patch 🙂 [![](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/a/a/aa366d2f45485b0c569b96ede266af64fb7f0ed6.jpeg "MODULAR SYNTH DIY - DUCKING SIDE CHAIN MODULE") ](https://www.youtube.com/watch?v=u6-yCLnolyg) And the verified stripboard here > [@Verified Stripboard Layouts!](https://lookmumnocomputer.discourse.group/t/verified-stripboard-layouts/81/400): > > Dual Balter Gate Delay from NLC Pics, schem, video … DUCKING SIDE CHAIN original schem from [Juanito Moore](https://www.instructables.com/Freestyle-High-Fidelity-Ducking-Circuit/) Pics & demo video of my build here ---
**Author:** ![AfonsoPatinhas](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@AfonsoPatinhas](https://lookmumnocomputer.discourse.group/u/AfonsoPatinhas)\ **Post date:** [December 14, 2021, 11:59am UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/27 "2021-12-14T11:59:55Z")
Hey hey jackb! Great looking build! Could you send the layout for this? I don´t know how to convert this to pedal format from the rack layout 😕 Thank you so much! \<3 ---
**Author:** ![jackb](https://avatars.discourse-cdn.com/v4/letter/j/65b543/32.png) [@jackb](https://lookmumnocomputer.discourse.group/u/jackb)\ **Post date:** [December 14, 2021, 8:00pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/28 "2021-12-14T20:00:47Z")
I have gerbers for the circuit board I had made - would that help? ---
**Author:** ![AfonsoPatinhas](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@AfonsoPatinhas](https://lookmumnocomputer.discourse.group/u/AfonsoPatinhas)\ **Post date:** [December 15, 2021, 10:17am UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/29 "2021-12-15T10:17:35Z")
Yes that would be great 🙂 ---
**Author:** ![Bertindo](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/bertindo/32/22908_2.png) [@Bertindo](https://lookmumnocomputer.discourse.group/u/Bertindo)\ **Post date:** [February 20, 2022, 10:41am UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/30 "2022-02-20T10:41:16Z")
Hi, I noticed that the circuit puts out an inverted signal. I was wondering whether it would be possible to get a non-inverted signal. As a beginner in electronics i started puzzling and reading… Would this be a correct change to the circuit? Or am I seeing things too simplistic? [link](https://falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWEAWayDM7ICZfP8gJwLogBs2ISCkVApgLRhgBQAhiNgBxche3IyyPrV5gkTJGHjwQDGDOyEyFSAjAB2HMg01BUcDMgsATiHTZaYMimvgbVoywDu5y-c48Px19zE2-cmEfWxs7QWE7EIiPGP4oUxQhESoyUVpaXGN0Ml4ENJShdINjMzBCSmTA5IEtOETlIPAKptr4FgAlEEbki1bzFKQMqGhxQnEiDEgKlgBzT15GwLBuEpZNYWWNGxzeSzEqIxHEEA66AGcAS3OAFzYAOwBjOhcF8G23-YTfLy-MAMgvBC5UqkRamgcrxB7wCXghCXm6C4kQ+SM2gLWiORKDg5mxGEoGShLWQuMCpKJrmhyxJuJC5L6-xQfXpXgpbwJCQ2HNxu2ZlAgNBkxzUpwu1zuTxe8z+7j+CEJCS6Sy8fUCtFI8SGJVGCHGCEmWBmZhVYha6pQdVKzUogTtXja9T5esoWGEZA0rsgwQSZiIO29VBaboMWUS6AV5lyKGQvD5jnaHAsGsD-vMgcI4Ak4kMRwY2GgKg0FW4hGRhDLyAg+cLHuIeHy6k9+Fz7Vc+Dj0bT8de3a7jRDIQjrujIZ7rjHo8Dyd9nAxM7H7gTbc+qrlDtei417hnxgAHnJpJ4QLpzBBNsJLvcAG50Ew3OgAExYB6YEGwOnAuE4NBQnGE9wAPb3AwV63veT4sIBJ79KSFaGOQaChjB6BQceNQ4vBR4rNABy2nGLBAA) Thanks for getting me on the road! ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [February 20, 2022, 10:54am UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/31 "2022-02-20T10:54:04Z")
> [@Bertindo](#): > > I noticed that the circuit puts out an inverted signal. > I was wondering whether it would be possible to get a non-inverted signal. This is precisely the principle of the Side chain, otherwise a simple VCA does the trick. but it’s surely possible … ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [February 20, 2022, 1:31pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/32 "2022-02-20T13:31:44Z")
I assume you mean the audio is phase inverted, not the inverted change in amplitude. I think your linked solution would work, although I would omit the voltage divider / pot and just use a fixed input resistor — I don’t like output voltage dividers, I prefer keeping the output signal high and doing attenuation on the downstream inputs. Or if you want that pot, why not just one fixed resistor and one pot in series on the inverting input? What you have would behave nonlinearly, almost all the change happening in the first 20% of the pot rotation, since it’s a large pot with a small resistance to virtual ground on the wiper: ![image](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/1/2/12102304c62f70b937b21f68d44bd28eafd5fd74.png) I’d also use 10k instead of 100k for the feedback and input resistances (including the pot), for a lower noise floor, and I think 220R is too small for the output resistor, I’d use 1k. ![image](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/4/9/49e505404b068959d909a905ee6ea0ba6dc9ac68.png) ---
**Author:** ![knopsl](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/knopsl/32/23478_2.png) [@knopsl](https://lookmumnocomputer.discourse.group/u/knopsl)\ **Post date:** [March 2, 2022, 6:44pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/33 "2022-03-02T18:44:53Z")
> [@jackb](#): > > rail splitter chip what is this “rail splitter chip” named? ---
**Author:** ![jkb](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jkb/32/26136_2.png) [@jkb](https://lookmumnocomputer.discourse.group/u/jkb)\ **Post date:** [December 17, 2022, 11:03am UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/34 "2022-12-17T11:03:41Z")
I did a PCB in Kosmo format with components on the panel in case someone is interested: > **[GitHub - polykit/kosmo-sidechain: Kicad PCB and schematics for...](https://github.com/polykit/kosmo-sidechain)** > > Kicad PCB and schematics for sidechain/ducking module in Kosmo modular synthesizer format - GitHub - polykit/kosmo-sidechain: Kicad PCB and schematics for sidechain/ducking module in Kosmo modular ... ---
**Author:** ![Edgard](https://avatars.discourse-cdn.com/v4/letter/e/9de0a6/32.png) [@Edgard](https://lookmumnocomputer.discourse.group/u/Edgard)\ **Post date:** [March 7, 2023, 9:11pm UTC](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998/35 "2023-03-07T21:11:51Z")
Hey jackb, I also really want to adapt this circuit for guitar, but I’m pretty new to circuitry, so I was hoping you would have a layout you could share. Great adaptation [Previous page](https://lookmumnocomputer.discourse.group/t/side-chain-module-ducking/2998.md?page=1)