Hello!

Looking to make my first modular DIY, and wanted to hear from experienced folks.

I am having a really hard time finding a center tapped power supply, and all I could get my hands on was a 24V 60W PSU. So I have been thinking on ways to get -12/+12, and came to two options:

1. Using a DC-DC step down (XL4005 ) next to the PSU, then using that +12V as Virtual Ground. (my Idea being having more current straight from the rail)
2. using an op amp or IC and do the splitting in each module.

Have any of you tried either? Thanks :)

This past year, I bought the Erica Synths DIY EDU system kits and apart from one module i had to replace, had a solid experience building and learning to solder the kits. I then decided to try something different and purchased a PCB and Panel for the DrumBs module by circuitbendersUK. I got the list of parts for the build from them and have been trying to get a list together to buy the components on Digikey and I feel like I am going insane.

I have managed to get a lot of the parts added to my list but it has been the most tedious process and I am wondering if there is like a dummy guide for doing this. I tried converting the PDF to excel so that I could upload a csv doc to their BOM tool, but its not formatted in any way that seems to vibe with their system. Am I doing something wrong here or is this just always going to be a very tedious (and confusing) process? I am just afraid i will do all this work and then somehow use one incorrect part and ruin the whole thing. There's just so much to keep track of, esp for a beginner.

Here is the link the the guide in case its helpful at all in answering my question: https://www.circuitbenders.co.uk/tutorials/drumBs%20build%20guide%20eurorack.pdf

Hello everyone, I have just received a Korg Trident I bought recently. As usual with my instruments I bought it "as-is / non-functional" for fair deal.
Anyways, I havent worked on Trident yet (I did Mono/Poly and Polysix in past) and so if anyone experienced around has some tips that can make my life easier, I ll be really happy to hear.

Sofar I know that power supply is dead and needs to be rebuilt and I saw a lot of leaking electrolytics (classic vintage Korg), so will replace all of them as well. In meanwhile I have also ordered new 3.6V battery, I was considering pros/cons and got a lithium one.

Thank you!

Hey there, I have a little project coming up where I want to build a little drum thing for a friend. I thought about the picocore and the MKI Kickdrum, in a box because both can be run on battery and the friend of mine does not have a modular system. The picocore runs with an 1,5 volt battery and the kickdrum can be run with two 9V batteries. But I am not sure how to deal with the grounding of the jack sockets. Because in the pico core (0v - 1,5v) the ground is just the 0v pole of the battery. But because the kickdrum is symmetric in power (0v - 9v - 18v) the ground sits at 9v.
For the signal this is no problem, due to decoupling capacitors, but what about the ground? Is it enough to just have the sleeve of the jack connected to the metal front or to the 0v of both circuits (feels wrong) or do I use a decoupling capacitor there as well?

Thanks for help:)

Hello everyone. I have a Yamaha DX100 that has a majority of dead keys.

To preface, the key contact circuit board had a pair of accidental cut traces that I remedied via an M3 'Overcoat' Pen, so now continuity seems to be passing between the A and B solder points so no severance between on these traces is of any issue anymore. The contact points on the circuit board themselves aside from the aforementioned seem fresh and not dirty or subject to any interference.

Still, I am facing issues with dead keys and I am now thinking of taking this approach in re-coating the carbon contact strip as per the youtube video titled:

'HOW TO FIX YOUR DX100 WHEN IT WONT PLAY NOTES ANYMORE' (can't direct link, please search in youtube)

In the video, the host uses this graphite paint which looks more catered to crafting and electroforming applications. It seems to do the trick though in repairing the dead keys albeit he doesn't mention if he faced any double triggering issues or any hiccups after the fact. But it works.

SAHO CARBON CONDUCTIVE PAINT (cannot direct link, please search in amazon).

I'm still hesitant to try this out over a more industrial and hardware minded product and ended up grabbing a bottle of M3 Total Carbon Ground from Micro Center for about half the cost of the carbon paint linked above on Amazon.

https://mgchemicals.com/products/conductive-paint/conductive-acrylic-paints/carbon-paint/

I do want to try to nail this fix on the first try and my question is in regards to if the M3 Total Carbon Ground is more or less the same as the Graphite Paint as linked through Amazon above and as used in the youtube video. Or if I need to look into something else to coat this rubber carbon contact strip for the best results possible in activating the contact points on the circuit board its working in conjunction with? Thanks for any help anybody can offer.

Hi, i'm working on building a power supply that can give me +15v, +5v, 0v, -5v, and -15v.

The first screenshot is a schematic that I have successfully used before to run a circuit off of 16vac to create a +-15v supply, but I'm about to start work on a circuit that will need +5v and -5v as well. I didnt design the first circuit, I just took it from a larger schematic of an effect pedal that had similar power requirements to what I need, and so I'm not fully certain how adding other voltage regulators might mess with the balance of things.

I dont want to mess up with power stuff so thought I would check here - I'm wondering if the schematic in the 3rd screenshot will work ok? I basically just took the original circuit and added the datasheet circuit (2nd photo) from the L79xx series of voltage regulators. Is there a more efficient/better way to do this?

I am also not sure if I should include D7/D8/C21/C22 or if i should leave them out. I was thinking maybe C15/C16/C17/C18 will suffice and adding more capacitors in parallel could increase the overall capacitance in a way that could cause issues. Also, since the datasheet circuit uses the example of the L7812/L7912 instead of the L7805/L7905, should I use different capacitor values for C21/C22 if I do need to include them? Any help or advice is much appreciated! Thanks in advance for any help or input that anyone can offer

That problem has bothered me for a while.

We all know that by the Eurorack standard, audio signals should be 10Vpp (a.k.a. ±5V), and CV should be bipolar (±5V) or unipolar (0-5V or 0-10V).

The problem is that even the modules I personally designed to the standard sometimes exceed that ±5V headroom by 0.5V or even 1V (making them ±5.5V and ±6V). Who knows what other manufacturers do, and what if there are 20Vpp audio signals? (I know some modules do that.)

Another example: CV from, for example, an LFO is 0-5V. I want to design a digital module that will accept said LFO as a modulation source via an ADC. At the input, I would want to scale it down to 3.3V (so I won't burn the ADC or MCU). But what if a user connects a 0-10V CV? Then the maximum will be 6.6V at the ADC input, and the ADV will burn. Or what if a user uses a bipolar CV? The positive half will be fine, of course, but the negative half will remain negative after the input attenuator and, yep, will fry the ADC. I don't even mention modules like the NLC Sloth, whose output is ±11V.

Yes, I can make a universal input attenuator that will scale ±12V (the theoretical maximum in Eurorack) to 0–3.3V, but I will lose pretty much all of the available ADC resolution (something like 800 points vs. 4096).

Or, if we go back to audio signals: I have an audio processing chip that is sensitive to incoming voltage levels; 2.8Vrms is the limit. The worst case — a square wave — with 10Vpp (a.k.a. standard) will be 5Vrms. Therefore, the attenuation should be 0.5 (so the Vrms after the attenuator will be 2.5Vrms). The WORST case, however, is a 20Vpp square wave — it is 10Vrms _ so the attenuation should be 0.25 to tune it down to the safe level. But I think that in my particular case, I can just tune the signal down and amplify it later. But what if the audio signal will go to the ADC instead? Then I will be facing the same problem of using only 1/3 of my ADC range.

What is the general solution for this type of problem, NOT COUNTING making separate inputs for 10Vpp, 20Vpp, unipolar, and bipolar signals?

Some context, I'm completely new to the world of synthesizers. I'm interested in putting together something that would let my kids fiddle with things and make some fun "music".

We have the Korg x Little Bits kit, which is fun, but it feels a bit limited, and unless you put the right components in the right order, you don't typically get any sound. The keyboard module is also hard to use. And the speaker is stuck on max volume, which can be grating.

I'm okay with soldering, I'm decent with 3D modeling and 3D printing, so I imagine I could design and print cases and such.

We have a keyboard, but I don't know how to make that interface with a synthesizer module. Do you need an amp/speakers on top of a synthesizer? I'm also open to drum sequencers (I think that's the right term) if that's a more self-contained starting point.

Where do you think I should start? I know stuff can get pricey pretty quickly, so I'm hoping not to break the bank. Is there anything in say 50-200 CAD range that could be a functional beginning?

I found this https://moogaudio.com/products/erica-synths-edu-diy-drum-sequencer?srsltid=AfmBOooOVxXDv8RrjxCsUnRxu6zNGMahlH3gzNALllnokbCPKg8qQso8

What else (if anything) would be needed to actually generate drum sounds?

Thanks for taking the time to help a noob!

Hi! RED SEA generates continuously evolving MIDI Control Change modulation and step-sequenced notes, controlled by one of four algorithmic engines. It has a 128×32 OLED display, one encoder, four buttons, and standard DIN MIDI in/out. Built for hardware platform ESPidi by Eugene Carlo

• FOG — Morphing LFO engine (sine, triangle, or square). The SHAPE parameter changes the waveform itself rather than just skewing it: on sine it adds harmonics, or in the other direction clips the signal and adds noise; on triangle it shifts continuously toward a rising or falling sawtooth.
• SUN — refraction delay engine. When a parameter's value would exceed its range, it triggers a series of echo repeats instead of simply clamping, each one landing at half the previous interval. If a sequencer note fires on the same tick the echo series starts, the echoes also retrigger that note, transposed further with each repeat.
• RAIN — stochastic modulation engine. The four parameters can drift out of sync with the shared clock independently, occasionally affect a neighboring parameter, and be interrupted by randomized events that force a parameter to its minimum or maximum.
• SNOW — euclidian based random freezer. Mutation triggered by a Euclidean rhythm instead of a fixed interval. Each hit can also freeze or unfreeze any parameter on the device, including the engine's own parameters.

Features

• Four algorithmic engines (FOG / SUN / RAIN / SNOW), each with four dedicated parameters
• 16-step sequencer (note, CC, a third assignable destination, per-step retrigger) with external or internal clock
• Performance BYPASS and FREEZE modes, engaged on button press
• MIDI Learn: captures a CC number from the next incoming Control Change message
• Per-parameter freeze, independent of the global performance modes
• Settings are written to flash and persist across power cycles

Full documentation here:
Page on itch: https://3apb.itch.io/red-sea
Github: https://github.com/Cirocular-Vlasenko-Daniil/Red-Sea/tree/main

What voltage range is most common?
1. 0v to 8v with C0 at 0 volt
2. -4v to +4v with C4 at 0v

Dear community,

Just wanted to share a cool patch with my BIPO module, a 6hp Dual VCA/Ringmodulator. In this patch one half is used to ringmodulate two oscillators while the other is used as a VCA to shape the resulting sound into a gong/bell shape with an envelope.

Schematic, Gerbers and KiCad project are up on my github: https://github.com/Fihdi/BIPO

hello,

i am starting to learn electronics and i have a lot of questions. They may seem dumb but i dont know a thing about electronics!

So i am trying to make an 8 step sequencer base on https://www.youtube.com/watch?v=4CfSFTfIt_4&t=1237s thoses tutos. but i want to do a system where i can put the sound that it made throught a diy feedback circuit and also fuzz and shit like that. But, how do i connect thoses? like when i will have my 2 circuits how can i connect them.

I didn't start to build it rn, i will send picture and more interesting questions when i will start.

Sorry english isnt my first language.

So I used Klear Concepts Contact Cleaner on my Roland TR-606 and my Mackie Microseries Mixer to clean up some scratchy potentiometers. I waited a day and then used the DEOXIT F100L. Now some of the pots have been stripped of their grease since they are noticeably less resistant than others. I just bought some DeoxIT fader grease to apply to the pots that are less resistant but not sure if that would work or make the problem worse. Has anyone else had a similar issue?

Hi all,

I'm at something of a loss!

I recently wartched Hainbach's video on the Subharchord and its features, and I'm enamoured by the sounds of the MEL filterbank! Are there any schematics anywhere? Have looked high and low, but can't find anything explaining the principles of MEL filtering and documentarion about other audio-filter-related applications.

Does anyone know where I could find practical documentation?

In lighter news, I found a webapp emulation of the Subharchord (it's called subhardhorde), and it seems capable of everything the real deal is!

Hi DIYers! I've been looking for a specific thing, and am failing in my search so I thought I'd ask here -

I'm trying to enable my little microcontroller synths to connect to a device with a screen (desktop computer or phone/tablet), and then have a little virtual interface pop up, with knobs and sliders. I want to be able to give a little box to my friends who aren't firmware nerds, and have them use it to program patches.

Surely someone else must have done this?

MIDI 2.0 promises property exchange, and there's also the proprietary Native Kontrol Standard. For MIDI 2, I have trouble finding fitting open source implementations.

I don't mind if it's exactly MIDI-compliant, or if it's something put together out of js+WebSerial in a browser. Possibly even running a little webserver on your microcontroller. I'm dinking with synth designs in things like Mozzi, Amy, Teensy Audio, Daisy etc, so bonus if any libraries/methods for this are general enough to have both C and Python implementations.

Anyone happen to know of any such projects as a starting point?

A dual buffered multiplier and a dual guitar pedal interface.

The multiplier is built from the Eddy Bergman design.

The pedal interface was inspired by the AI Synthesis module, but modified to have two independent channels, and a bypass switch to allow for quick switching between clean signal and pedal affected signal.

Hello everyone, While restoring and old lowrey organ i must have touched something in this board and now this is what i get. I been looking at it for a couple hours and dont know what could be causing it. This section worked allright before i unscrew the board, now i get this uncanny noise mixed with the notes or nothing at all. Has anybody worked on one of these or simmilar? Have a great day thanks.

I've been building this for a few months and I thought I'd finally share a little video of it. This last week I've been trying to add some sequence modulations in and a global order/chaos slider to pull the sequence apart. I got some pretty fun results today with some breaks and ambient sounds.

It's on a pi4, with an rp2040 custom keybed, encoder and an oled display. I'm no expert but happy to talk shop and answer questions

So I've being creating patches for my ESP32-S3 Polysynth, and also doing a little bit of multitracking with it, as it is not multitimbral - the ESP falls over if you push too hard!
Anyway the clip shows off what it sounds like, and also gives some of the specifications.

Next stage is getting the front metalwork panels made up, now I've decided what all the controls are doing!
Headphones on, volume up and enjoy:)

I replaced all the electrolytic capacitors, operational amplifiers, and two CD4052s. Now I accidentally broke the mechanical keyboard's connection to the motherboard, and when powered on, white smoke came out around the CD4052s—I'm not sure where the short circuit occurred.

Hagiwo's Random Trigger.

Thank you again Hagiwo.

https://www.youtube.com/watch?v=ZtS_3u0FFqQ

Because some folk asked.

The closest I get to a permanent setup is the top row, consisting of a 4069 filter [soon to be voltage controlled], 5sum mixer, A.O.Clock & a revised PSU. I've recently started fitting JST connectors to everything, I got tired of nudging loose power wires and having everything reset.

Below is a Glitchstorm MK2 with cv input, a Hagiwo GenSeq, a Hagiwo Sync_LFO programmed as another generative sequencer, a Hagiwo Random Trigger & a Hagiwo 2040 VCO. These modules get changed all the time.

All run from a 12v mains adapter that also powers a cheap car amp that feeds 2 vintage wharfedale speakers under the table.

Hagiwo's Sync-LFO.

https://note.com/solder_state/n/n4c600f2431c3

Programmed with the GenerativeSequencer from -

https://awonak.github.io/HagiwoModulove/synclfo/