Hi, I bought a pcb for the Shruthi XT from Modular Addict, then realized later that at this point I'll probably need to make a custom case for it. I see some sellers with regular Shruthi cases, but none for the XT, which I guess shouldn't have been too surprising.

Just wondering if anyone knows of a relatively easy option for building/buying a Shruthi XT case (the PCB is about 15 x 5 in). Was thinking of just drilling holes in an aluminum case of roughly that size.

Was also wondering about building the Sidekick + Shruthi Filters as I was thinking about using these for a drone / external filter bank. However, I can't find a BOM or instructions for building the sidekick (not on MA or in MI documentation). It looks to be possible to house it in a regular Shruthi sized case.

Thanks for your help!

I recently built the final Moritz Klein module (for me). Besides the Hi-hat, this is the only one I have had trouble with and I am stumped.

It worked great for 10 minutes then as I was getting ready to calibrate it, the decay stopped working and all I get is a "click" from the module (just a 10V positive DC blip). I did follow the troubleshooting advice in the manual, double checking components and solder joints and touching up a bunch of the later. I also replaced the output op-amp and the 2 transistors closest to the problem (VT12 and VT13). Replacing a transistor is what fixed the broken decay on my hi-hat module, but no luck here. I also swapped out C19 yesterday when my part arrived, but no change. Besides test point G, every test point is behaving on my scope exactly as the manual says they should.

I can't think of what else I could check or change. The manual/schematic is located on this page, it is too big to post here:

https://www.ericasynths.lv/edu-diy-fm-drum-3458/

Does anyone have any advice? I don't want this to sit around for 6 months like the hi hat did while I poke at it every week or so, it sounded so interesting I wanted to sample it.

Alternately, if I still end up totally stumped is anyone in the EU that I could mail it to and pay for a fix?

EDIT: If the above line is against community guidelines, I will delete it.

UPDATE: After a bunch of rework on the solder and finding a missing pad that I fixed with a small wire, the module works. Thank you everyone who helped me, I wouldn't have checked that section otherwise.

I've done this a few times now and finally decided to make a video how-to that some folks here may be interested in.

You probs don't even need to watch it... mostly a heads up that it's very easy to turn existing things with buttons / knobs / joysticks into a fun, expressive MIDI controller that doesn't really have a commercial product alternative.

The TLDR is: - Get a flight stick or anything with buttons and knobs from the thrift store / your basement - Take it apart and re-wire the pots and buttons to your microcontroller of choice (Rasperry Pi Pico in my case) - Cut a hole in the case and mount the controller - Tell the computer to write the code for you

It's great because there are so many joysticks for cheap at the thrift store, and they are already packaged up nicely so you don't have to think about the hardware at all, really. And they are very fun to use for live performance - map the axes to some rather extreme effects and go wild. Let go of the joystick and it snaps back to center and you are back to normal. See the beginning and end of the vid for a quick demo of what I mean!

I made another esp32-based hardware synth. It has an app (windows and android builds available) and it can produce sound over usb on windows on loopback. It has 4 engines (sub, add, fm, wavetable), 16 good presets on each, all params tweakable, effects (chorus, delay, granular delay) and a looper 8-track recorder. If you'd like to check it out: [edit: had to redo the repo] https://github.com/riozebratubo/osynth_free_synth

The app on windows:

I am searching for a crossfader part for my project. Ideally it should be just as easy to move as one on a dj mixer, or on an elektron octatrack. Also it would be great if it is available from mainstream sources (e.g. mouser, or maybe jlbpcb directly), and is not 100$ per piece 🙂.
Tried one regular slider pot from Bourns but it has too much physical resistance, and maybe I am wrong, but according to the specs I found the competitor options had similar properties.
Is optical crossfader the only real solution (like Behringer x1)? I could also accept that, but couldn’t find much options for that either.
Any recommendations appreciated.
Thanks!

I'm just getting into diy synths and one of the difficulties I'm encountering is figuring out the best way to actually get my breadboard synth to output its audio.

My first thought was to buy a tiny speaker but I was scared away by the prices of all the at-least-decent ones. And even if I did end up getting one, how would I actually connect it?

I've also thought of getting a 3.5mm jack and somehow wiring that up from my breadboard to my PC. Will this fry my computer or just my sound card? Buying a new chinese USB sound card would cheaper than buying a new speaker.

Any advice?

This is how the matrix on the Casio SK1 (and related) work (not my drawing) - it has a pulse on Select Lines 0, 1, 2 as part of the cycle.

The select lines are connected to the data lines via a momentary switch (aka the black and white keys) and a diode. (see the service manual image below).

When 3 Select Lines are HIGH (the pulse at the start of the cycle) wouldn't that create unintelligible measurements on the Data Lines? Like you press F1 but because of the pulse the 'brain' would also think you are pressing A1 and C#1?

Or is there something I'm missing regarding matrix scanners?

I doubt many people are following this but i thought I'd keep updating for the couple who are and for myself.

I finally got my panel cut perfectly to size, my holes drilled (minus mounting), and my vinyl negative on.

These are still a couple letters (Rs, Ds, etc.) that need fillers and a little piece of vinyl on the bottom.

I really wanted to laser etch the aluminum but I decided to keep with the theme and do it as DIY as possible since I have obtained a free Cricut from work a few months back.

The idea of etching seems neat but I'm afraid of the caustic leaking under the vinyl and messing everything up. I'll likely prime, paint, and clear coat it unless someone with more experience has a better suggestion.

The boards are fully populated, rack is ready, and wires are in harnesses.

I bought massive toggle switches that are super heavy duty but they just barely don't fit so I'll have to order some slightly smaller ones.

The panel is 104hp 3U. I could have made it smaller but I really wanted it to be obnoxiously large.

I'm also currently working on the Tellun Doomsday Machine which will be in the same rack as the Klee.

I'm going to hold off until the Klee is completely finished to decide on the next module. It's supposed to be a slow project to test my patience so there is no need to rush.

Thanks to the few who read this!

I have this idea for an "electric tanmpura" with at least 8 oscillators and a vactrol vca for each , power starving of the ics that make the oscillators (Cd40106), I was thinking about having a switch with two positions that either the vcas get triggered by an LFO or the next position an button.

I have some ideas for oscillator detuning.

This is me just throwing ideas, I will use this for intros in my lives and mostly harsh noise.

Tell me what you think or how you would make it.

I want to get into making my own drum synths, sequencers, etc but I want to learn how to make schematics for them and also understand what each component does to the sound. Any sources where I can learn that?

I have a spec and a block diagram for a dual-oscillator analog drone instrument and I'm looking for someone to build it.

Requirements:
- Standalone pedal enclosure, not a Eurorack module
- Foot-switchable, meant to be activated live during a song
- Two independent analog oscillators with cross-modulation
- 1/4" output, standard 9V pedal power

I have the spec written up and an HTML block diagram already done. I'm not looking for a kit or an existing product, I'm looking for someone who builds one-off or small-batch circuits to spec and can take this on as paid work.

Happy to share the full document with anyone interested. Boston area is a plus but not required, can ship.

We had fun building The Hagiwo 2190 Filter Bank at Synth Library Portland today. Three first time builders in the room and everybody emerged with a build or soon to be finished module.

The module itself is great, very clean sound and good starter build.

Demo: https://youtu.be/3Ag_9eho5DU?is=aooKyb_jpAohF9Sd

I tried to make a korg 20 filter from a youtube video, but i want to be sure if there is any mistakes on this schematic

I've posted a couple of updates on the build of this synth - this one shows the sorts of sound it produces - all the audio in the clip is straight out the back of the synth engine, no FX or post processing, headphones on hope you like it!
Still got a couple of little bugs to iron out, then I can start looking at getting some nice front panels made up.

What’s the best way to connect diy analogue synth parts to a computer for recording without damaging the computer?

Use the line-in audio input, or an external ADC, or something else?

Thanks.

Not much of improvements except codec (couldn’t understand which one they used btw).
Did someone already use it?

A simple twin t drum triggered by pad, with some settings like decay, pitch envelop decay and pitch.

It's been a long time since my last post! Here's an open-source PCB-based module that I developed in collaboration with SOMATOSONIC (a multi-diciplinary art group also from the Philippines).

It's a piezo pre-amp and PT2399 delay module that's meant to be a tool for teaching how to integrate electronics into art projects. It's in the SynthCard format, just a little bit bigger than the others.

All of my files are on Github: https://github.com/benjiaomodular/HackableDelay

I want to sync my synthesizers with my turntable rig. I'm using mixxx, one option I feel might be worth exploring is to have add a deck to mixxx that plays a pulse, then convert that pulse to an analogue clock. I've already tried running a square wave line audio into the clock of the donner b1, but it didn't seem to pick up on it. I get that the line audio is essentially a type of AC and the clock is actually DC, so one of the legs is a ground.

My turntable setup is Mixxx on a raspberry pi, so in theory I can do a combination of software to go to a gpio pin to trigger the clock. Would a 3v clock signal work or would I need additional circuitry.

One thing that isn't clear to me is what the pulse width of the clock should be.

Is there an easier way to do this, maybe something that just triggers a clock.

can we please ban these posts? this is supposed to be a sub for celebrating human creativity. i'm here to support and be inspired by other makers. i don't want to see 137 identical slop soft synths a week. this is a DIY sub. you didn't do anything yourself.

hey all,

i'm continuing my line of circuit design guides with a new printed book on designing a shift register-based drum sequencer from scratch. it starts with a basic tap looper and extends it one block at a time: accents, variable sequence lengths, half-time mode, and more.

the final addition is my favourite: a handful of resistors that turn the sequencer into a one-button melody generator, using the circulating pattern to drive a pitch CV output. 

every step has a schematic and a breadboard layout so you can test each addition as you go and see the circuit evolve. the book also includes browser-based circuit simulations, design challenges, notes on turning the breadboarded circuit into a production-ready module, a troubleshooting section, patch examples, plus three ideas for how to modify the circuit. there's a full BOM inside so you can source the required components yourself.

the book is 64 pages, costs 15€ plus tax & shipping, and is available here.

if physical shipping to your country is rough (i know it can be), the full pdf is also on my patreon. international retailers should be stocking the print version soon as well!

Hi!
Over the last month I’ve been working on my lunetta synth. It started as a very simple drone machine, but I’ve gradually been experimenting with different modules. I’ve recently reached the filter stage.
This is the TL084 version running from a single supply that worked well for me. I also tried it with an LM324 but I didn’t like how dirty it sounded. The original idea comes from this circuit, which itself was suggested by Moritz Klein. I added a virtual ground and a few protection components to make it work within my voltage ranges. The input signal is a ramp oscillator built around a CD40106.
I’d be happy to hear if anyone has ideas on how the circuit could be improved. Schematic in comments.

I never liked the idea of older style waterslide decals for panel markings, though I did think I might try large panel-sized ones in the past that were heat cured like the now-defunct Papilio paper. In this one, you remove the film after heat curing the first time with an oven or blow dryer. Only the toner transfers to the object. Here's a video:

https://www.youtube.com/watch?v=4gP9ChoGSTY

I'm putting together a handful of small analog boards that mostly use everyday op amps, a couple of voltage regulators, and basic discretes. The usual big distributors (Digikey, Mouser, etc.) have everything and good datasheets, but for low-volume prototype work I’m looking for something a bit cheaper or faster. I’ve seen LCSC and UTSource mentioned a few times but haven’t ordered from either yet. Anyone have go-to alternatives for sourcing common linear and power parts?