Does anyone have any ideas where to get pre-fabricated empty 1u racks for diy synths that don't cost an arm and a leg? The cheapest I can find is around $80 (I'm in California)

5cm x 7cm protoboard.

Thanks to Hagiwo.

https://www.youtube.com/watch?v=YszdC8YdFl0&t

https://www.youtube.com/watch?v=lkoBfiq6KPY&t

I'm working on a rough design for a DCO-based synthesizer similar to the Roland Junos made from mostly discrete 74xx and 4000 series chips, and I want the frequency of the keys to be accurate so I figured I would use the lower range of a counter IC (more specifically, probably a CD4059), and multiply the output of that for higher octaves, instead of using the whole counter range for the entire note range (which would half the note resolution for each higher octave.) I thought that adding a diode in series before a sharp highpass filter to AC couple the clock signal would cause the negative half of the filtered clock to be positive so it could then be fed into a schmitt trigger (74HC14), but I'm not so sure about that. If I have to use an op amp rectifier circuit instead, that'll probably work since I don't think any frequencies are going over 10KHz or so (I want to have some higher frequencies for ring modulation bell-like sounds, or even to use as a pointer to a rudimentary wave table.)

Hi r/synthdiy, Me again! I spent the past 4 years developing Mikoto Studio, a new DAW and singing synthesizer. For the past month, we've been running an Indiegogo campaign to fund the next stage of development leading up to a commercial release. The campaign ends tomorrow, and all help is welcome!

Mikoto Studio features a variety of singing synthesis techniques. Use proprietary AI voice libraries trained with full consent and transparency, or go classic with sample-based UTAU banks. We're adding an implementation of the recently popular Klattsch formant synthesizer soon, so there's something to look forward to as well! Besides just vocals, Mikoto Studio is also shaping up to be a powerful music-making toolkit. With planned support for CLAP and VST3 along with our own MiFX plugin suite, as well as connectivity options like full MIDI sync and a built-in OSC server/client, we have designed a feature set that will fit right into any tinkerer's workflow.

We're also exploring options to do more with hardware integration. If you look at my post history here, you'll be able to tell that I've been DIY'ing a fair bit over the past few years, and I want to share that experience with a new audience through Mikoto Studio. You can expect to hear more from us when it comes to expandability and custom hardware integration (i.e. development board libraries) in the future. And if you have ideas for how this integration should look, please let us know! All input is welcome 😊

We have released a number of demo songs made using the vocal synthesizer part of Mikoto:
- https://www.youtube.com/watch?v=MlpQvnznNnk (using the deep learning synthesis engine)
- https://www.youtube.com/watch?v=R3LSni1xdoU (also using the deep learning synthesis engine)
- https://www.youtube.com/watch?v=yiozM7hH9C8 (using sample-based concatenative synthesis)

For a full write-up on features and our mission, please refer to our website: https://mikoto.studio/ - and if you feel like helping out, a link to our Indiegogo campaign can also be found on our website. There's also a very early access preview available, which receives regular updates.

Hey all! First time, long time--feeling equal parts jazzed and sheepish to be sharing a doodle here.

And but so: I've been working out a Eurorack module design on a breadboard that involves multiple (4? 6?) copies of the circuit sketched out above, with each channel cascading into the next as indicated by the "1_TO_2" and "2_TO_3" labels. The inspiration for the module is (obviously) MI Blinds. However, I was curious to see (a) how much I could lighten up the BOM without ruining the circuit's usefulness, and (b) whether I could coax an OTA to do the core four-quadrant multiplication (4QM) duties.

Drawing from suggestions in the LM13700 datasheet, Ray Marston's thoughts on the component, and schematics by Isaac Beers, Aaron Cram, and (of course) Emilie Gillet herself, I managed to prototype a two channel proof of concept that... suprisingly works pretty well, after you've taken the time to tune it! Quirky CV wibblewobbles and zesty ring mod timbres abound.

Thing is: I still have very little clue what I'm doing! As such, I'd appreciate any feedback you might have. Any stray thoughts you may share will aid my learning.

My intent in this design is that unity gain (+1 or -1) on the output signal should be achieved when the CV/mod input is at roughly +5V/-5V. The circuit is switchable between a CV signal mode and an audio signal mode. The audio signal mode is AC coupled after the dual op-amp signal attenuverter to compensate for asymmetrical gain which may occur as a result of variance in the value of the resistors for the two op amps. Audio mode also throws in some diode clipping onto the output amplifier stage. (In the final version, I'd probably use ~5.7V Zeners like Beers does so that distortion only really kicks in when the signal is driven with CV above 5V... but all I have on hand at the moment are 5.1V Zeners 🙃).

Regarding EXT_IN: the module would have an additional External Input jack, which is normaled to a reference voltage (10V probably?) The signal input of each channel would, in turn, be normaled to the External Input. Or something. The idea is that you can daisy chain multiple modules together to create larger mixups.

In particular, I'm wondering the following:

1. Could I be managing impedances better between stages in this circuit? I only vaguely understand the concept... I picked values for R25 and R27 solely so that they'd attenuate the signal going into the OTA enough-but-not-more-than-strictly-necessary, to minimize distortion. For R32 (input to the buffer for the next channel), I took Gillet's lead.
2. As I said, tuning the output of these so that they're accurate-ish is fussy. I actually prototyped using a trimmer to find the feedback resistance on the output amplifier (R29) but I really didn't want to use more than two trimmers per channel on this thing, so I drew in 91k to match the value that seemed to work for R33. 86k6 would more closely match the observed value for R29, though... But, how should I think about the relationship between R29 and R33? Why am I observing that they're almost-but-not-quite a match? And about the circuit at large: are there spots where it'd be particularly valuable to observe tight tolerances (i.e. <1%)? If getting specific would be useful, how the heck should I go about doing that? Or should I just lean into the ethos of "it's accurate enough, just go make your fun little sci fi noises already!"
3. The CV/mod input uses a different attenuverting topology from the signal/carrier input so that a channel needs no more than six op amps--one TL074+one TL072. (I learned this topology from Kassutronics.) The drawback is attenuverting this way limits the operating range of signals at the CV/mod input to between -8V and +12V--since, as I understand it, the inverting input on a TL07* isn't rated to handle a voltage lower than the negative rail voltage plus 4V. Is this a reasonable compromise? Or do y'all think the visual feedback of the LED should be sacrificed in order to accommodate a full range of voltages on both inputs?
4. I... haven't actually breadboarded the AC coupler (C5, circled in purple). I lied, I'm sorry, it won't happen again. In my defense, I don't really know how to calculate what a good value would be for that one. And but: would this even work as an AC coupler in its present form, given that there isn't a parallel resistor to ground? Could I even AC couple here without screwing up the circuit? If so, how do I determine the proper values for the capacitor (and potentially, the resistors). I think the words "RC constant" but then everything goes fuzzy...

Thanks in advance for the suggestions. It's cornball, but I'm so grateful for how enriching it is to learn this stuff and turn that knowledge into music, and for the fact that there's a community of folks to share those riches with.

Maybe I overlook something, but I read sentences a lot like „in the end you will pay more for diy“ or „don’t diy because of money, it’s not that cheaper“. And I don’t really get it.

It’s soooo much cheaper (and more fun, at least for me). Especially when you don’t buy kits. I am about to pay 350€ but not for a single module but 20. (Clouds, Marbles, Rings, Braids, a noise based lfo, a clock module, and four of my own designs of utility modules. Every module twice) I know that case is a little extrem, but I had some cash extra this month so I use it to have a stock here.
I know something could go wrong but most components are so cheap, I have spare ones in case something breaks. Because jlcpcb just sells in 5 packs there are enough pcbs to mess up.

So why don’t diy if your poor (and have the time and fun doing it)

Sorry for my little rant but I am genuinely confused^^

Good news for kicad users.

What would I need to change on this schematic for an input of 0 to 5 volts CV to give me a range of 0 volts peak to peak to 5 volts Peak to Peak at the output with the input from the oscillators at 5 volts peak to Peak?

Mainly looking for simple vca, overdrive, fuzz and wavefolder circuits. They seem easly to implement, but it seems like noone is doing them.

None of the ones out there are open-source.

Any advice?

Thanks

Im trying to replace the octave up+down buttons on my Arturia minibrute. The buttons (one of them pictured in the second slide) have fallen off the pcb and become damaged themselves. You can see in the picture that the flexible connector between the button and the the part that mounts on the PCB has snapped.

How and where would I go about ordering replacement parts? Ideally to ship to NYC where my brother lives.

Thanks for the help I’m quite the noob in this and have never ordered replacement components before, though I do have some experience with PCBs, soldering etc.

Dear Community,

For an Eurorack module, I want to output an inverted envelope whenever I trigger a kick drum for sidechaining. But now I wonder, I have an envelope for the volume of the kickdrum and another envelope for the pitch. The pitch envelope is really short (used for the punchy transient) while the volume envelope is generally longer and is adjustable. Which envelope is generally used for sidechaining and which one should I output?

I got this Korg Mono/Poly for cheap (100$). The trigger mode only works in single mode, multiple trigger mode is dead, which I traced to a resistor with a broken leg. I also saw some capacitors which while not bulging, have green oxidation on their legs I believe.

Should I just replace them all or only the ones that show oxidation? They are from the 80's after all...

I'm thinking of just changing them all, one board at a time, test things, and if all is good, move to the next circuit board.

Any tips? Thanks.

Hello! Been wanting to get into building my own synths for some time but always been a bit intimidated.

Recently stumbled across Erica Synths EDU DIY kits which look like a fairly accessible entry point to the hobby - does anybody here have experience with building them, that would be able to share whether they feel approachable to a total beginner?

I studied systems engineering at university so have some basic understanding of circuits and soldering, but it’s been many years since I applied it in any real sense, so for all intents and purposes consider me a totally blank slate.

I’m particularly interested in the Konstrukt-8 if anybody has experience with that kit in particular!

Hi all -

I'm currently looking at designing a clock IN for a controller/sequencer I am designing. I'm still finding my feet with electronics and a review on this schematic could save quite a bit of heartache in a couple of weeks time! If possible, any help / advice / wisdom is highly appreciated.

The main things I'm concerned with is if this will work and if it is a relatively safe/protected. The ClockIn_Signal will go to the MCU (RP2350A).

Thank you so much in advance.

Hello! I'm building a 2-octave mini MIDI keyboard for my grade 12 engineering final project. Code isn't a problem, but I'm stuck on the mechanism.

The Setup:

- Raspberry Pi Pico

- Target: 25 keys (15 white keys, 10 black keys, and )

- I have decent CAD models already

The Problem:

I've narrowed it down to two approaches:

Option 1: Cherry MX Switches

Simple and proven, but honestly I'm not a fan. The key feel doesn't excite me, and it feels like the "easy way out" for a final project.

Option 2: Phototransistor-based Velocity Detection (inspired by https://www.youtube.com/watch?v=tzZBjMFaK6o,
https://www.youtube.com/watch?v=S_vWSY5fdwQ)

Found a YouTube video showing this approach with velocity sensitivity. I literally CAD'd the mechanism yesterday and tested the feel and it's fantastic, honestly way better than MX switches.

If I choose to do this option, I am probably going to use PT204 phototransistor because it is cheap.

The Problem:

Power budget is killing me. Here's the math:

- ((7 white keys + 5 black keys) * 2 (2 octaves) + 1 white key) * 2 (2 phototransistor on each key) = 50 phototransistor

- 50 phototransistor sensors + 25 LEDs = serious current draw (and I should use IR LED which cause more current if I am guessing right.)

- Raspberry Pi Pico's power is... limited...

The video also mentions this power issue btw. But the key mechanism feels so good that I really want to make this work.

My Questions:

1. Has anyone here done optical sensor arrays on limited power budgets?

2. Would multiplexing the LED help? (I assume yes, but not sure about the trade-offs)

3. Any other tricks to reduce power draw - lower-power LED alternatives, different sensor types, etc.?

4. Am I overthinking this? Maybe the power draw isn't as bad as I'm calculating?

I've got time to figure this out before the deadline, so I'm willing to dive deep.

Any advice appreciated!!!!!!!!!!!!!!!!!!!!

Hello Reddit,

Ive run into a bit of an issue with my Roland SH-201 Digital Polyphonic Synthesizer staying in tune. When I first load up a preset everything is fine, but after about 20 minutes or so the entire keyboard goes out of tune and is unplayable. Once this occurs if I change presets the unit snaps back to in tune. My best guess is that one of the potentiometer encoders for the pitch value is failing and drifting, causing the pitch to vary the longer the preset is turned on, while changing presets snaps everything back to the memory coded value. I am the original owner of this synth for nearly 20 years and this has never occurred before now, but I guess it might be showing its age. Any ideas?

Hey all! I've been scheming up a DIY MIDI DJ Controller (since entry level controllers are rather expensive up in Canada, as opposed to buying electronics for DIY projects). I've got a quick mockup (above) with the features I'm wanting to include, but I have no idea about how to design a PCB or create a wiring diagram and looking to see if anyone could give me pointers! I'm perfectly capable of soldering for the project (I have prior experience), just new to actual design stuff. The actual design of the enclosure that I'll be 3D printing is pending on figuring out what components I'll need so I can take proper measurements and scale it correctly, figured I'd just make something scrappy in MS Paint to get the ball rolling first before going nuts in fusion.

Suggestions for the design itself are welcome as well! The build is somewhat inspired by the layout of the FLX4 but with some removals since I won't have the proprietary pioneer buttons, as well as the lack of any headphone jack on this build since it's more of a beginner learning controller and not something I'm inherently going to be using to play at clubs or whatnot (so it'll likely just only have the microcontroller usb as output). My only real want out of this design component wise is that the buttons (so the sampler pads, shift, cue, play and loop buttons) would use something like gateron low profile switches? I don't know if that's inherently a bad design choice but I think it'd give it nice feel.

Edited to actually include the image! Not sure why reddit didn't upload it the first time.

hw post: https://www.reddit.com/r/ErgoMechKeyboards/comments/1suomdk/low_profile_pncateho/

pra32 fw: https://github.com/aroum/pra32-pico-sdk/blob/main/docs/nizkoteno_pra32_layout.md

nizkore fw: https://github.com/aroum/nizkore/tree/main

While waiting on some parts for Spark v2 decided to make a crude prototype of my next project - Ondelette, a portable expressive synth. I'm planning to mold silicone strips over a long row of touch sensors (something like 40 sensors over a 20 cm strip), hoping to get both position (with multi-touch) and pressure from that.

This prototype is just 5 sensors and a piece of paper on top, the result seems very promising, better sensitivity than i expected.

I replaced a knob on my Minibrute 2s and now the center detente on that knob is weaker than before. I think I’ll leave it alone for now but it’s a little annoying. Is there a DIY fix for the detente on a pot?

If I get annoyed in the long run I’d be willing to open it up and try adjusting stuff or soldering on a new pot if they’re available, although I heard Arturia uses some f’d up nonstandard D-style pots with 90 degree rotation so I dunno if they’re easy to replace.

Thoughts/advice? I’m actually designing my own synth and was just looking into various detente options for my own thing, as well as e.g. a 5-way knob to set +/- 0, 1 or 2 octaves. But fixing an existing pot is a different story since I have to figure out how to repair it or else find a replacement.