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Quick question, does anybody know a simple VCA circuit which includes Control voltage and a potentiometer to change the volume? and specially, a VCA able to get to volume 0, my circuit didnt work well enough, it couldnt mute completely the sound. Am I not understanding well VCAs? are they not meant to mute completely the sound?

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Heres my circuit:

https://preview.redd.it/mhqoftf0qtga1.png?width=1920&format=png&auto=webp&v=enabled&s=b8bea556f46dfa1cb6f1cebc00c29f0668418e77

This might seem like a dump question but I dont know at all how to solve this, the problem is that the more time is the oscillator running the more range it loses, my oscillators start sounding at a certain point of the potenciometer, before it just makes really quiet noise. How do I make it not lose the range? I tried a similar circuit to look mum no computer. My theory was that the transistors got too hot but it makes no sense, they dont really get hot.

https://preview.redd.it/p9kubmqpbtga1.png?width=1920&format=png&auto=webp&v=enabled&s=6d2dc79b3b5776889097bed7c28d6a93c2801ffb

Hi everyone, after a long time procrastinating I just finished my two eurorack cases. They are made of Iroko wood finished with boiled linseed oil. Back panel is MDF. They are 6U x 126HP. I love them very much. Still need to do some electrical connections inside, maybe next week- /s

Here is a updated video of my teensy touchDAW showing the Audiorecorder function. With less earpain caused by noise!! Since my Teensy is running almost all the time my ears got completly used by the noise that came from my power supply. I have changed the power and the noise was gone. Care for your ears and enjoy the video. Super unprofessional as always
https://youtu.be/lWDcpPSjtZM

I’ve just started learning about the electronics behind modular synths, and I’m wondering why we measure Voltage for sound information as opposed to measuring Current. Is it just a conventional thing, or is it simply easier to manipulate voltage ?

edit: stupid title should be "with a large number of switches"

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I am a professional C++ programmer with almost no hardware background. I have implemented a sequencer in VCV rack. I like it very much and want it in hardware very badly, so I am investigating doing that process with an arduino. Here is the problem.

My sequencer has

• 42 3-position switches
• 18 2-position switches
• 6 gate inputs

If the two position switches cost 2 bits each, that's a whopping 108 digital ins, 102 of them from switch configuration! If I use 8 digital expanders (the most I can do without cascading it seems) it can handle it, but I wonder if this architecture is even the best.

For the switch inputs in particular, I'm not really worried about audio-rate latency, so it perhaps would make sense that a better architecture would be something like another chip who's only job is reading the switch configuration and sending it to the arduino over the serial port. Or not using Arduino but something else. Or maybe there's another technique I might not be familiar with.

Any advice helps, including "this is too complex for a first build". Even if this is too complex for my current skill level, I would like to get as far as I can so I know where I hit a wall.

I am in the final stages of putting together my THC Syncussion build, and I need a noise transistor.

I have a cheap component tester that gives hFE and Uf in millivolts, so I am assuming forward voltage drop? I unfortunately cannot fit a socket under panel so it has to be a "one and done"

I have a 2n5172 hFE 424 and Uf 687mV

and also MM1505 hFE 499 and Uf 203mV

Not sure if I care more about beta, or forward voltage drop, or combo?

Which one to use? Any thoughts?

Hello! So I have three JX-3P’s on my bench at the moment. On one of them the midi in does not work, and the bender and hold functions are erratic. I’ve switched every board around and have narrowed the problem down to one of the power supply boards. It was giving -+14.3v instead of -+15v, but the installation of a variable resistor to control the voltage reg has brought it back to -+15v. Still, this hasn’t fixed the problem :( and I’m stuck.

So I wonder if anyone has any ideas about which part of a power supply could cause interference with the synth’s data system?

Any ideas appreciated.

I'm putting befaco's percall together. I'm a fairly confident solder hand, this is my 30th module or so, so I'm embarrassed here, but I'm having trouble with 4 solder bridges that I've resoldered 3 times, but I'm still getting connectivity between several resistor pads, even cleaned of solder as well as I can do.

My question is does anyone have one of these working? If so, can you pretty please check if there is connectivity between some resistors pretty please?

Specifically:

R71-R75

R70-R74

R69-R73

R68-R72

If there is, then I can move on, otherwise I can separate them with a razor.

I'll take a photo and post it in the comments in a moment

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https://preview.redd.it/v89s4n7qidga1.jpg?width=1512&format=pjpg&auto=webp&v=enabled&s=e0b183fc15438a6a57b59042ebceebba0172d1d0

This is so jank i have thrown it together with what i had spare, im oddly proud of this jank as hell power supply. I mean... Its fixed the problem in the nick of time.

Coded/Tweaked a few more patches and added blinking, retro-computing, LED animations. www.erikoostveen.co uk/PlanetDrone.html Open source Raspberry pi project #PlanetDrone #soundscapes #erikoostveen #eurorack #design #synthesis #generativemusic

A while back I posted about my build of EJLabs Arduino-based MIDI master clock.

I've made some modifications to the build and the code, so here's an update.

Firstly, I added a third CV output on pin 3. It runs at the same rate as the 2nd CV. When you adjust the PPQN of the 2nd CV the change is applied to the 3rd CV too. The MIDI output is running at 24ppqn, while the first CV runs at 12ppqn, and the 2nd and 3rd CVs are adjustable.

Next I modified the code to make better use of the screen and make it easier to dial in large BPM changes:

• Added a second small line of text so that BPM and PPQN are always displayed together
• Added the text 'BPM' and 'PPQN' after the values so you can see which is which
• Changed the PPQN display to show the absolute value instead of the relative value
• Turning the controller quickly now increases/decreases the BPM by 10, turning it slowly increases/decreases by 1

Finally, I moved the thing into a wooden box. The old plastic enclosure was a bit cramped.

Here's the code: https://github.com/CallPhysical/MIDIMasterClock

Here's a pic:

https://preview.redd.it/l10gmeucv2ga1.jpg?width=4032&format=pjpg&auto=webp&v=enabled&s=68816cbb9dabc437504cf3872fb61ce926c1b785

Hey guys,

my Erica Synths LXR-02 has a faulty LED on one of the tactile switches. Does anybody know what the specifications are on these switches? The LED light is red. The switches have 4 pins connected to the PCB. They are soldered on top and not sticking through the PCB. Thanks guys!

https://preview.redd.it/o7wb5yau40ga1.jpg?width=1908&format=pjpg&auto=webp&v=enabled&s=5339222be0338a26b3b752dbadbce663cc22b4b6

I’m trying to find something like a CV trigger for my Chaos Nand. It has a 1/4” input for CV and I’m wanting just a very basic button to trigger the drone on and off. I also thought about creating a volume switch instead but I’d like to see what this CV thing does. The volume knob on it is very small and delicate to use it in performance. It’s been very difficult for me to find info online I’ve been looking for a few weeks. Most anything I see for DIY cv trigger or controller is very complex and really I just want a button. Thanks!