# Simple Twin-T Kick Drum **URL:** \ **Category:** DIY STUFF\ **Created:** [December 9, 2020, 5:07pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460 "2020-12-09T17:07:50Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [January 31, 2023, 4:16pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/102 "2023-01-31T16:16:54Z")
The nice thing about having a second instance of a circuit is that you can compare them by measuring voltages left and right with a multimeter or scope and then when you find a discrepancy this may lead you to find a solution. Make sure to give them the same input signals and settings before you try comparing them. ---
**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:** [January 31, 2023, 10:45pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/103 "2023-01-31T22:45:09Z")
Maybe start by looking here > [@General advice for troubleshooting a module and asking for help](https://lookmumnocomputer.discourse.group/t/general-advice-for-troubleshooting-a-module-and-asking-for-help/2049): > > (This is a wiki post, please add and correct!) Look and see if others have had the same problem. Use the Discourse search facility to find topics where the module you’re building is discussed. Inspect your work. Verify all components are correct values. Look for solder connections that are rough, irregular, skimpy, dull, or missed completely (we all do that!) and reflow them. Look for solder bridges between pads and remove them. Check your power connection. If it’s a Eurorack style power cabl… Do you have any pictures of your build ? it’s from my stripboard version ? schem ? ---
**Author:** ![Jewceman1](https://avatars.discourse-cdn.com/v4/letter/j/b487fb/32.png) [@Jewceman1](https://lookmumnocomputer.discourse.group/u/Jewceman1)\ **Post date:** [February 1, 2023, 2:42am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/104 "2023-02-01T02:42:10Z")
Yeah sorry have been too busy to post! It is based on your stripboard layout and schematic! Here are some photos of my build! ![iDExqSo](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/e/f/ef2a9ae5bd1a539afa5576bc0357fadc38f388cf.jpeg) ![JbXcliV](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/5/c/5cf942ad4c4fd9fd17522284346dd8a611714fa1.jpeg) ![taDnUgI](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/d/6/d6bf6a40ae6ecde0c640aa4e59e5b626597ab52c.jpeg) ---
**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 1, 2023, 9:44am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/105 "2023-02-01T09:44:26Z")
For me the face with the location of the components looks good, have you checked the resistors values ? tried another IC ? pass a knife or cutter between the lines of the stripboard to avoid any possible short circuit between the lines ? here for example it is not very clear in the photo but can be suspicious for me (and sometimes it’s not visible to the eye) ![5cf942ad4c4fd9fd17522284346dd8a611714fa1](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/b/7/b73976b8e5bb8613925df10d05fa83d505003b4b.jpeg) ---
**Author:** ![Jewceman1](https://avatars.discourse-cdn.com/v4/letter/j/b487fb/32.png) [@Jewceman1](https://lookmumnocomputer.discourse.group/u/Jewceman1)\ **Post date:** [February 2, 2023, 5:37am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/106 "2023-02-02T05:37:22Z")
Yeah I did follow your advice and using an exacto knife I carved between every trace to cut potentially any unwanted bridges and touches up almost all solder points, and the progress so far is that I kind of hear the faint sound of what sounds like the gate signal going through but not really a coherent drum sound. At some point it sounded like one of the potentiometers was affecting something when moving it, but then I lost it. ---
**Author:** ![Bpbby](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/bpbby/32/15259_2.png) [@Bpbby](https://lookmumnocomputer.discourse.group/u/Bpbby)\ **Post date:** [February 2, 2023, 8:01am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/107 "2023-02-02T08:01:22Z")
Hi, Are you 100% sure that your TL074 (opamp) is working ? Or genuine ? Just saying this as I cant see any printing on it. ---
**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 2, 2023, 8:21am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/108 "2023-02-02T08:21:08Z")
if it’s better, maybe there is also a not very effective soldering point, redo some soldering and also have you > [@Dud](#): > > tried another IC ? … ---
**Author:** ![Jos](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/jos/32/151_2.png) [@Jos](https://lookmumnocomputer.discourse.group/u/Jos)\ **Post date:** [February 2, 2023, 10:57pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/109 "2023-02-02T22:57:16Z")
I always use one of these to check ALL soldering joints: > **[1.89US $ 39% OFF|30x Jewelry Diamond Jewelry Loupe Magnifier Tool Eye...](https://www.aliexpress.us/item/3256804025746694.html?spm=a2g0o.productlist.main.107.466fEdGDEdGDXH&algo_pvid=ef5dbcb4-cdd8-4f9f-93db-47b143299099&algo_exp_id=ef5dbcb4-cdd8-4f9f-93db-47b143299099-53&pdp_ext_f=%7B%22sku_id%22%3A%2212000028397223948%22%7D&pdp_npi=2%40dis%21EUR%213.57%212.18%21%21%21%21%21%402100baf316753785404233223d06d7%2112000028397223948%21sea&curPageLogUid=6Ik79SJWimZl&gatewayAdapt=glo2usa4itemAdapt&_randl_shipto=US)** > > Smarter Shopping, Better Living! Aliexpress.com ---
**Author:** ![Jewceman1](https://avatars.discourse-cdn.com/v4/letter/j/b487fb/32.png) [@Jewceman1](https://lookmumnocomputer.discourse.group/u/Jewceman1)\ **Post date:** [February 3, 2023, 9:09pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/110 "2023-02-03T21:09:16Z")
So I did swap out the TL074 on it the other day with others I had lying around and it output noise and the potentiometers seemed to actually work, turning them would change some of the tone of what is being output. It is outputting a type of noise, though nothing that resembles a kick drum sound. And it does seem that the gate signal is going through, whenever I touch the tip of the cable on the input, I do hear the noise being affected by it and when there is a gate signal going through, it can also be heard. It does sound like it is trying its hardest to output sound, it can only go so far. I’ve been double checking solder points and wires and have barely gotten any desired results. I’m not sure if it is the TL074s that I am using as they seem to have always worked and I even bought them off of tayda electronics, but I had a similar problem with a colored noise circuit I made where both the protoboard and PCB versions of the same circuit encountered a similar problem. ---
**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 3, 2023, 10:52pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/111 "2023-02-03T22:52:47Z")
you are talking about Gate signal, but for this type of module (to have a short kick sound) it is a Trigger signal that must be sent what are you testing with ? btw if by changing the 74, the potentiometers work there is already some progress 🙂 ---
**Author:** ![Krakenpine](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/krakenpine/32/3263_2.png) [@Krakenpine](https://lookmumnocomputer.discourse.group/u/Krakenpine)\ **Post date:** [February 4, 2023, 12:32pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/112 "2023-02-04T12:32:45Z")
The trigger conditioning circuit actually turns gate signal into a trigger signal, unless the gate signal is way too long and gap between gates is short. But 50% on and 50% off gate signal with any sane tempo should work here. ---
**Author:** ![saint\_et\_moudulard](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/saint_et_moudulard/32/12683_2.png) [@saint\_et\_moudulard](https://lookmumnocomputer.discourse.group/u/saint_et_moudulard)\ **Post date:** [February 10, 2023, 2:01am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/113 "2023-02-10T02:01:31Z")
Yes I confirm that resonant twin-t networks are very noisy and really sensitive to external interferences. I never had exactly the same results for 2 identicals circuits. I’m experimenting this type of drum circuits for a long time now, so I have noted several important details to troubleshoot them: First it is really important to verify your wiring! (more than 70% of problems I had with these circuits come from here); Some poorly laid cables can quickly act as an antenna; if your circuit doesn’t work right away, delicately and carefully fiddling around with the wiring until you hear a sound, can often help to determine where the source of the problem is. Also, I noticed that it is very recurring that the problem comes of the decay/resonance pot; either by too long or badly insulated wiring between the pot and the pcb, or else because of bad solder joints on the legs of the potentiometer. Verify connections of frequency tuning pot too, don’t forget that here the two potentiometers act on each other ! The best design choice would be to use through-hole components for pot/socket, soldered directly to the pcb, like for a “sandwich-mounting”. It eliminates a lot of problems related to “spagethi” type of wiring… But it necessite to design your own PCB (in CAO) Sometimes, the strange behavior of Twin-t filters makes them really esoteric… but when they work they become very satisfying!! Currently I am studying resonator gamelan circuits, which are very similar to twin-t in design, and their are enough sensitive too… but they produce a really interesting and nice drum sounds ! (cf the Tinkle drum module by NLC, inspired by a 70’s concept of Paul DeMarinis, used for his Pygmy Gamelan synth) I hope this information will be useful to you, keep me informed and above all don’t give up, the result will be worth your effort ! Have fun ! ---
**Author:** ![AriaSalvatrice](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/ariasalvatrice/32/28804_2.png) [@AriaSalvatrice](https://lookmumnocomputer.discourse.group/u/AriaSalvatrice)\ **Post date:** [April 7, 2023, 6:25pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/114 "2023-04-07T18:25:34Z")
So, I am experimenting with this circuit, planning to build it using @plop’s PCB schematic (but not the PCB itself), and I’m not sure if I’m actually getting it to work! I’m building it step by step on breadboard first, and building the Twin-T core, it seems the decay section has no effect? I can’t see or hear any effect… I just get a pop. I can alter the frequency a little if I build the other “T” however. I don’t really understand this circuit, maybe I need to build the distortion and output section before it works? I tried to build it twice on breadboard, once the full core, once just the decay section and the 1M resistor. I’m using TL072’s (known good supplier) to split it on multiple boards. I know I experimented with Twin-T drums with CMOS chips a few months ago and the circuit was super fiddly too. ![](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/8/1/818670dff0550337da6108473b15d0847df2d5fa.jpeg) I added a manual trigger but it’s otherwise (intended to be) almost identical to the original circuit, this is my WIP redraw (I like to redraw things to understand them better and make them fit on printouts) ![image](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/a/8/a819ff964625b1343227758cad635556e92b4c35.png) ---
**Author:** ![Plop](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/plop/32/11707_2.png) [@Plop](https://lookmumnocomputer.discourse.group/u/Plop)\ **Post date:** [April 15, 2023, 8:28am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/115 "2023-04-15T08:28:42Z")
Hello, i take a look at what you redraw, the two resistors in series in the decay path are 470k. It should work just fine with CMOS as R1 and C5 act as a high pass filter and should convert any gate to a short pulse (you can try different value for C5 to vary the pulse length). here is a link to a workshop i followed while building it (the decay path is explained) → [here =)](https://helsinkisoundelectronics.files.wordpress.com/2015/11/analog-bass-drum-workshop-updated.pdf) Also i just finish a newer version of this design, i’ll post the link for the schem/pcb/thing here as soon as the upload is finish =) ---
**Author:** ![Plop](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/plop/32/11707_2.png) [@Plop](https://lookmumnocomputer.discourse.group/u/Plop)\ **Post date:** [April 15, 2023, 10:01am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/116 "2023-04-15T10:01:47Z")
Here we go, the old Drum-k is in the “OLD” github repo and here is [the new one](https://github.com/Pl0p/Modular_Synth/tree/main/Drum-K_MKII) There are few adjustments that can be done it’s being too loud and have too much low end for my taste, also the pin header positions are not the best and the accent level could not fit on the I/O board because of them so it’s just a fix 10k resistor for now. There are all quite simple fix it will be better in the next batch =) Also because i use the sandwich way, it could be done easily in Kosmo format ---
**Author:** ![AriaSalvatrice](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/ariasalvatrice/32/28804_2.png) [@AriaSalvatrice](https://lookmumnocomputer.discourse.group/u/AriaSalvatrice)\ **Post date:** [April 15, 2023, 1:46pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/117 "2023-04-15T13:46:29Z")
Thanks, since then I have rebuilt the circuit a few times and never got it to work yet, I tried multiple resistor values (i was cross-referencing multiple circuits). I’ll take a look at this version next time I try it out. ---
**Author:** ![ShedSynth](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/shedsynth/32/22450_2.png) [@ShedSynth](https://lookmumnocomputer.discourse.group/u/ShedSynth)\ **Post date:** [April 17, 2023, 6:07am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/118 "2023-04-17T06:07:18Z")
Perhaps [this](https://shedsynth.wordpress.com/drum-a/) version might help, also based on [Analog Bass Drum workshop](https://helsinkisoundelectronics.files.wordpress.com/2015/11/analog-bass-drum-workshop-updated.pdf). ---
**Author:** ![Swirv](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/swirv/32/26090_2.png) [@Swirv](https://lookmumnocomputer.discourse.group/u/Swirv)\ **Post date:** [April 4, 2024, 3:48pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/119 "2024-04-04T15:48:11Z")
hey folks, i built the twin-t bass drum from duds layout and it works great with a gate from my sq-1 @ 5v however i can’t get it to trigger from an lfo like i can with the rest of my percussion modules. is this where the “gate to trigger” circuit should step in or am i not understanding correctly? simply can i achieve this with some minor tinkering? ---
**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:** [April 4, 2024, 4:03pm UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/120 "2024-04-04T16:03:39Z")
The gate to trigger is here: ![image](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/3X/9/5/95a348b4742fc4ada5f1a825a25fb3560a2dbdd7.png) Presumably your LFO either is too low amplitude or too slow rise time to make a trigger. You could try increasing the value of R2, or maybe increasing C1. Swapping R2 for a 20k pot would allow a front panel trigger sensitivity knob. ---
**Author:** ![Swirv](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/swirv/32/26090_2.png) [@Swirv](https://lookmumnocomputer.discourse.group/u/Swirv)\ **Post date:** [April 6, 2024, 12:17am UTC](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460/121 "2024-04-06T00:17:56Z")
Thanks man I will try that. [Previous page](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460.md?page=5) [Next page](https://lookmumnocomputer.discourse.group/t/simple-twin-t-kick-drum/2460.md?page=7)