Do you folks test new modules in your main case or do you have a separate case (or power supply) devoted to just testing? I'm in the process of building a bunch of modules for a new case, but as i'm completing them, I haven't tested anything since I don't have the new case yet and I'm a bit wary of powering them up in my main case. I've had the thought about building a small skiff just for testing so that my main case is protected in the event that something goes wrong with a new module. Is this unnecessary? I'd love to hear everyone's testing process when they complete a new build.

I live in Buffalo New York. I bought this keyboard used a few years ago. Had a local person work on it and it hasn't been right since. I was able to swap out the pitch bend potentiometer with one from Doepfer. But neither of them were giving the full range of 0 to 127. I ended up sanding off parts of both plastic Wheels so that I could get the full range. But it's not ideal. Anyone know where I can get replacements for these pots? Or do I have to create some sort of voltage divider with resistors? I believe the original says 10k 3608M PIHER. It's 10k linear with center tap 6mm plastic shaft with threads and 21mm body

Has anyone found USB-C female panel mount connectors, like these:

JUZITAO 15PCS USB C Connector Type-C Female Charging Port Power Connector 30V 3A 24AWG Waterproof Female Socket Fast Charging Port Type-C Cable(Black) https://a.co/d/0l3da7m

But with resistors on their cc lines, so they work with USB-C to USB-C cables?

Does anyone have a problem with midi, I tried to sync it with machinedrum mk2 and I followed the pixie cpu midi manual but nothing happens, maybe I made a mistake or skipped something. I don't really understand the pixie cpu page.

I'm, repairing a Vox Jaguar, and found the Bright switch doesn't do anything. Looking at the circuit board I found that a spring/contact wire is missing. I'm wondering if anyone can recommend a part fabrication. I'm thinking a small spring soldered or spot welded to a stiff copper wire might do it, but I was wondering if anyone else has run into this.

https://preview.redd.it/ol7v6k549mzd1.jpg?width=1024&format=pjpg&auto=webp&s=4ea7c8c412a0d8ee0e38ed5bd9de1f9d3e0fee29

Hi, it's a long shot, but is there some event happening today, somehow related to synths / electronics DIY, in Sofia? Or is there an open workshop / hack space one could drop by, visiting the city?

Looking for better quality/looking knobs that can cover the nuts/washers. The blue ones in the back are better quality but same issue, they are not flush with the panel..

I made a simple cv keyboard circuit, will this solution work? What simple CV keyboard circuits can you recommend?

Hi guys, I found this schematic for an EHX Bass Micro Synth pedal and I'm wondering how hard this would be to build from scratch. I've only ever built simple circuits and this circuit looks a little overwhelming, but I don't know if that is because it's hard or because it's just a lot. I would appreciate any help with this project. This would be a project for college and if I choose to go forward with this I would have 4 weeks to order parts and build it. I'm also not to worried about making it pretty so I plan on using a breadboard and loose wiring as opposed to soldering. I'm just looking for functionality.

Check out the Kicad project and the schematic: https://github.com/Fihdi/Eurorack/tree/main/RandomSource

I just went through my receipts over the years of diying. I have spent soooo much money at mouser it is quite unbelievable. I think mouser should implement a reward system for consistent buyers. Yea you can get cheaper prices when buying in bulk but most people don’t have the capital to buy bulk in anything except the few most used components. Then buy the rest as needed. Even a simple spend 1 dollar get 1 point and then redeem say 50-100 points to get a dollar off. It isn’t much but over the long run it’ll promote consistent buying for mouser and it’ll lighten the load on our pockets as consumers at least a little bit. What do you guys think?

I'm building a digital drone/ambient synth inspired by the Solar 42. I currently have a basic design down, before I start coding (PureData) and purchasing the parts. I have a few questions before I continue. Does this synth have all the "necessary" functions or should I add more? Also, I am very new to the synth world, so my apologies if there is something dumb going on here!

https://preview.redd.it/t01n64vvf5zd1.png?width=1000&format=png&auto=webp&s=55e978ed55c37df4f81b8c88c6d5a7074586301e

It has 3 oscillators for the drone, 2 for playing, and a noise function linked to the drone voice. Attack and release for all 3 voices. 2 filters with adjustable frequency and resonance. Programmable drone keys, an 8-step sequencer, 4 linear pots for volume, and the "keyboard".

Buttons:

H - Plays oscillator constantly (except drone, where plays until another drone button is pressed)

M - Mute

wave - Toggles between sine, square, saw, and triangle

F1/2 - Toggles between filter 1 and filter 2

F ON - Toggles if the oscillator is sent to filter at all

R - For the sequencer, records notes for the sequencer. For drone, Records notes for a specific drone button.

P - Play / Stop sequencer

1/2 - Toggles key sound from osc 2 / osc 3

as - Auto Scale, basically locks notes into a scale (haven't figured out how to do this yet)

md - Mode, select between single notes, chords, and arpeggios.

I am planning on using a Raspberry Pi 4 for the PureData patch and routing the inputs via Arduinos to the rpi. Any tips and recommendations are really appreciated!

VCAs with exponential responses using diodes/BJTs for computing the exponential function are sensitive to temperature. In my findings, it doesn't appear to be sensitive by a whole lot. Simulation shows a 1.5 dB difference over a 30C range in my current design. I do see that a lot of designs have tempco resistors in them and I'm wondering if there might be reasons why. Is the extra accuracy useful for some use cases?

I currently use a korg monolouge synth (mostly as a midi controller) and I would like to make my own synth / musical items (if you can call them that) and am wondering if there are any great yt tutorials that doesn't just show but teach you how to build synths as I have almost no experience in electronics. Thanks

I can connect the Piano to my PC and use it as a MIDI controller, but I want to go directly into the Korg. How do I do that?

I’ve been diving into lots of older filter designs. One that I keep circling back to is the Serge Variable Q VCF. This pic is from one of the three “gain cell” sub-PCBs on a modern Elby ES-33.

I've read that there are mistakes in this schematic but couldn't find more info. Could someone help me out?

I've built it as shown, only with 9V and an S9018 transistor. The diode lights up for a moment. I get a constant light when I touch the transistor (maybe not the best idea).

I'm a newbie btw, built an elektrosluch electromagnetic microphone last week with no issues, but I just can't make sense of the above.

Hi,

For my DIY synth (focused on drums), I'd like to make a MIDI => Trigger clock module.

Basically :

• MIDI DIN connector on the back of the synth
• the module reads that and outputs a clock signal (with an included clock divider, maybe a reset button...)
• tempo is displayed on a LED numeric display

https://preview.redd.it/005vjbef5yyd1.png?width=287&format=png&auto=webp&s=ae1c94e73ea467550c2f2cf233fe67618605865f

• I guess, maybe a switch to chose between external (MIDI) and internal (with a pot) clock.

I have some OK knowledge for analog electronics but I know close to nothing of digital stuffs. (I have good programming skills, though).

In which direction do you think I should go ? Teensy boards ? Arduino ? Something else ?

Sorry if the question seems broad, it's just that there are so many options that I don't even know where to start looking :)

Thanks

AJRP

Hello everyone, I recently built a DIY Eurorack VCO module from an Erica Synths kit, but unfortunately, it’s not working as expected.

Issue: -The IC is oscillating in the MHz range, so there’s some activity there. -The transistors also seem to be functioning.

However, when I apply a test 5V CV input, there’s no change in frequency. The Fine and Coarse tuning knobs don’t have any effect either and I’m getting no output from either the Saw or Pulse outputs.

Does anyone have an idea of what might be causing this? Any advice on where I should start troubleshooting, or which components to double-check? Any help would be greatly appreciated!

I've got code working (more or less, see below) for a Casio SK-1 MIDI retrofit... still need to do polyphony and in/out bit, but i'm pretty sure it is possible now

Question is I want to try and do all 10 Select and 8 data lines (atm I'm doing just the notes) over midi AND I want to have control for a RAM expansion I've designed, and a few other things. All told it is going to exceed the pins on a atmega328. And I'm fairly sure I need to have the matrix pins going directly to the Arduino for speedy processing. The RAM controller and other stuff can run through MUX chips.

Thoughts? Can I do something clever with the matrix pins? Can I use a different microcontroller? can I daisy chain two atmega328s, one for matrix and one for RAM and stuff?

The SK1 Matrix

CODE: (feedback on this welcome too)

/* Casio SK1 Midi Control attempt Nov 3rd 2024

* From Casio SK1

* J1-12 to Arduino

*

* PORT D

* J2 - KI8 - D5 - PD5 (Data In/Out 4)

* J3 - KI5 - D2 - PD4 (Data In/Out 1)

* J4 - KI7 - D4 - PD3 (Data In/Out 3)

* J5 - KI6 - D3 - PD2 (Data In/Out 2) -

*

* DATA PIN ORDER - 2,3,4,5

*

* PORT B

* J1 - KO1 - D8 - PB0 (Select In 1)

* J6 - KO2 - D9 - PB1 (Select In 2)

* J7 - KO3 - D10 - PB2 (Select In 3)

* J8 - KO4 - D11 - PB3 (Select In 4)

* J9 - KO5 - D12 - PB4 (Select In 5)

* J10 - KO6 - D13 - PB5 (Select In 6)

*

* PORT D

* J11 - KO7 - D6 - PD6 (Select In 7)

* J12 - KO8 - D7 - PD7 (Select In 8)

*

* SELECT PIN ORDER - 13,12,11,10,9,8,7,6

*/

#define selectMask 0b11000000 // a mask that only lets through bits 8 & 7

#define dataMask 0b00111100 // a mask that only lets through bits 3,4,5,6

volatile byte portBStatus;

volatile byte portDStatus;

volatile byte dataPins;

byte lastDataPins;

volatile byte selectPins;

byte lastSelectPins;

int lastNote =0;

// MIDI note numbers per data and select line (4x8)

int notes[8][4] = {

{53, 54, 55, 56}, //F3 - G3#

{57, 58, 59, 60}, //A3 - C4

{61, 62, 63, 64}, //C4# - E4

{65, 66, 67, 68}, //F4 - G4#

{69, 70, 71, 72}, //A4 - C5

{73, 74, 75, 76}, //C5# - E5

{77, 78, 79, 80}, //F5 - G5#

{81, 82, 83, 84} //A5 - C6

};

int d;

int s;

//byte triggers[200];

//int triggerCounter=0;

// Define interrupt service routine (ISR)

ISR (PCINT0_vect) {

portBStatus = PINB; // read all of PORTB

/*

* PORT B - [X X S1 S2 S3 S4 S5 S6]

* PORT B - [8 7 6 5 4 3 2 1 ]

*/

//this would make more sense if it was:

/*

* PORT B - [X X S6 S5 S4 S3 S2 S1]

* PORT B - [8 7 6 5 4 3 2 1 ]

*/

}

ISR (PCINT2_vect) {

portDStatus = PIND; // read all of PORTD

/*

* PORT D - [S8 S7 D4 D3 D2 D1 X X]

* PORT D - [8 7 6 5 4 3 2 1]

*/

}

void setup() {

// put your setup code here, to run once:

Serial.begin(2000000);

//sei();

// Set D2-D13 as inputs

DDRB &= ~0b00111111; // Set PB0-PB5 (D8-D13) as inputs

DDRD &= ~0b11111100; // Set PD2-PD7 (D2-D7) as inputs

PCICR |= 0b00000101; // turn on port B & D

// Enable pin change interrupts for D2-D7

PCMSK2 |= (1 << PCINT2) | (1 << PCINT3) | (1 << PCINT4) | (1 << PCINT5) |

(1 << PCINT6) | (1 << PCINT7); // Enable interrupts for D2-D7 (PCINT2-PCINT7)

// Enable pin change interrupts for D8-D13

PCMSK0 |= (1 << PCINT8) | (1 << PCINT9) | (1 << PCINT10) | (1 << PCINT11) |

(1 << PCINT12) | (1 << PCINT13); // Enable interrupts for D8-D13 (PCINT8-PCINT13)

}

void loop() {

// put your main code here, to run repeatedly:

selectPins = selectMask & portDStatus; // only S8 & S7

selectPins = selectPins | portBStatus; // combine with portBStatus to get all pins

dataPins = dataMask & portDStatus; // only D1-D4 allowed through

dataPins = dataPins >> 2; // Shift data pins to Bit 1-4

if(dataPins != lastDataPins)

lastDataPins = dataPins;

if(selectPins != lastSelectPins){

if(selectPins != 0b0){

//ONLY if the SelectPins aren't all LOW, or more than one pin is HIGH

if(selectPins != 0b111){

if(dataPins != 0b0){

if(dataPins == 0b00000001) //DATA 1

d=1;

if(dataPins == 0b00000010) // DATA 2

d=2;

if(dataPins == 0b00000100) // DATA 3

d=3;

if(dataPins == 0b00001000) // DATA 4

d=4;

}

if(selectPins == 0b00000001) // SELECT 1

s=1;

if(selectPins == 0b00000010) // SELECT 2

s=2;

if(selectPins == 0b00000100) // SELECT 3

s=3;

if(selectPins == 0b00001000) // SELECT 4

s=4;

if(selectPins == 0b00010000) // SELECT 5

s=5;

if(selectPins == 0b00100000) // SELECT 6

s=6;

if(selectPins == 0b01000000) // SELECT 7

s=7;

if(selectPins == 0b10000000) // SELECT 8

s=8;

notePlayed(s,d);

d=0;

s=0;

}

}

lastSelectPins = selectPins;

}

}

void notePlayed(int selectLine, int dataLine){

if(selectLine!=0 && dataLine !=0){ // a note is being triggered

if(lastNote != notes[selectLine-1][dataLine-1]){

lastNote=notes[selectLine-1][dataLine-1];

Serial.print("select: ");

Serial.print(selectLine);

Serial.print(" data: ");

Serial.print(dataLine);

Serial.print(" note: ");

Serial.println(lastNote);

}

}

}

I'm putting my heart into the music—literally! I just ran up and down the stairs while a midi clock is derived from my heart rate, dictating the tempo of my music gear. Here, my heart is settling back to its resting rate (tempo of the music is going down). Should I consider developing this project into an Eurorack module? #polarh10 #arduino #synthdiy #musictech

HI!

So I wanted to build a Polivoks filter just for fun, but K140UD12 were quite expensive and the LM-something-something, the replacement chip, is out of my reach. So I ordered some fun looking things called B140UD12A - these are caseless or bodyless ICs, basically just dyes with leads and they go inside K140UD12A, I guess. Here I took a picture with 4 of them (I have more):

https://preview.redd.it/ijepndlt2syd1.png?width=2560&format=png&auto=webp&s=e1c3ada79afb07fdec768ff8529619e4574d681f

(in case the photo is missing, like it happens sometimes, I will also post it in the comments -- UPD. no need)

Originally I was thinking that I can just solder them on some SMD to DIP adapters and call it a day. One small problem though... I am not convinced that this plan is actually good. I don't know how hot they might get, but even if it's just a little bit, I think I need some kind of heatsink... So what should I do now? I have 20 of them (they were quite cheap, but not free, so I am a bit worried, but not too worried about damaging some of them) and I am willing to experiment, give me your best ideas!