Has anyone here built this kit or had USB issues with modules which use the RP2 B2 (R2040) chip?

I can’t install the firmware as there’s no disk mounting via USB on my Mac, and nothing listed under System Information. I’ve tried with two MBPs, one via a hub (as there’s no USB-A ports) and the other (much older) directly.

I’ve confirmed with a multimeter that various ICs are getting the correct voltage to the relevant pins, the power header is correctly oriented and there are no shorts between the pins. All solder joints have been double checked and re-flowed where necessary. Flux removed with isopropyl alcohol. I was very careful not to overheat anything while soldering but I don’t know how to confirm that something didn’t get fried.

It’s a pretty simple build since a lot of the components are pre soldered SMD and most of the soldering relates to the pots/jacks and not anything which should affect the MCU side of things. I’m hoping it’s just a Mac USB compatibility issue, and I’ve contacted RYK for advice but in the meantime wondered if anyone else had a similar problem with this build or something else that uses the RP2 B2 chip?

I’d appreciate any pointers!

Do you think I could power the fuzz factory on 12v? Just looking for distortion solution for my case and have two fuzz factory clones built. I figure an attenuator might be a good idea on the input. Not really looking for any cv control here but maybe some home rolled vactrols in the future would be fun.

My Attempt

Eddy Bergman's Design

My stripboard component side

sandwich

https://preview.redd.it/a952e4u7bmge1.jpg?width=4080&format=pjpg&auto=webp&s=4b872cd6ce3a0ffaad7790bd5375b405f0037f5d

https://preview.redd.it/hckhhy28bmge1.jpg?width=4080&format=pjpg&auto=webp&s=8a64ff0940858b69087cc3cb682353de4e68f560

Hi All,

So having built a number of modules from PCBs I decided to try and build something off a stripboard diagram off Eddy Bergman's site. I changed out a few things to fit it to Eurorack format, and made a silly mistake in my pin placement, but it seems to be okay. No magic smoke.

I am having some issues getting the DC offset to 0 off the output jack, I get -12v from the x3 gain out and -.215V from the normal out. The trimmer doesn't seem to do much at all, is it the orientation or different type of trimmer? I tried adding a capacitor in the line of the output but I don't think I fully understood how to implement the DC removal effect and it didn't seem to do anything. I could use the advice and would love to have another pair of eyes on this. Thanks!

I'm wondering if people normally add a ground plane on both sides of their modular PCBs or just one side? I have several designs to send off but I haven't seen a valid answer to this conversation and I'd hate for them to come back noisy or faulty. I'm not sure if it matters much, and to me both sides may look better, but my top layer often serves no real purpose as a ground plane. So do I keep the top ground plane but do not link it to a net?

Dear community,

Current mirrors keep on being the best circuit! Here is a two way current mirror design with just 6 components, excluding the load resistor.

Simple Two way Current mirror

The output current is actually inverted (mirrored you can say heh), so 1 mA into the circuit results in -1mA through the load, so the output voltage becomes negative and current goes from ground into the output. The output voltage is -(Input Current)*R.

To get a Two way current mirror without inversion you can chain two such circuits together. Using Opamp feedbacks, or another set of NPN / PNP transistors on the outputs you can have current amplification.

Here is the same circuit as above with stabilized virtual ground input, this removes the forward voltage drop on the first set of transistors.

https://preview.redd.it/5gipx7yywjge1.png?width=685&format=png&auto=webp&s=5d4262d541903d8b1946df1c930f1cf23cb6c817

TLDR: I need 64 knobs to control Ableton synths, mixer, and DJ fx for my live set. I have never done a DIY electronics project but from YT it doesn't seem that intimidating. Will a DIY midi controller with 64 pots be cheaper than a Faderfox pc12 or two Launchcontrols XL? Do I learn a new skill that might be useful (but not the objective) or submit to GAS and find money for expensive quality gear?

Hello everyone

Could anyone help and give some advice from experience? I have been working on a techno live set in Ableton for a while and have run into the bottleneck of needing a proper midi controller with pots (and maybe faders). Since my only experience with DIY is watching all the youtube videos I need some help with estimation of price and effort.

My goal is to play music live but I don't have that much money for gear. If I decide to make a MIDI controller myself, I would learn a new skill that might be useful, but the goal is make music, not to be good at DIY.

With this in mind I want to understand how much effort and money it would take for a 64 knobs DIY midi controller. If there's a website that can help me calculate it, could you please share a link, otherwise below is a brief description of my Ableton synths and what controls I need for them. I have zero understanding of which board/chip I need.

Does it make sense to do an 8 knobs prototype to learn some DIY skills and then build a 64 knobs controller or does it make sense to just buy a faderfox or a bunch of smaller controllers? What would a 64 final controller + prototype cost?

The project itself

As the title says I need 64 pots/knobs and 4 buttons for my set. I am also open to faders for stuff like mixer faders and ADSR on my Juno-like synth. In total I need 64 controls that require moving a knob/fader and 4 buttons to switch some presets.

1. Kick: 1 gain, 5 sound controls
2. Bass/kick/tom: 1 gain, 6 sound controls
3. Clap: 1 gain, 2 sound controls
4. Hat: 1 gain, 2 sound controls
5. 303: 1 gain, 5 sound controls, 2 buttons for saw/square wave and distortion type
6. Juno: 1 gain, 7 sound controls
7. Filler saw: 1 gain, 7 sound controls
8. 3*7 sends (1 reverb and 2 delays)
9. Master DJ effects: 2 knobs, 2 buttons for preset changes

All synths I have made myself with Ableton stock devices based on existing hardware instruments.

Now I need a hardware midi controller. Accounting for all movable controllers I need 64. All pots might be easier but 12 faders (7 track + 4 Juno adsr + 1 DJ effects) + 52 pots can be cool.

Currently I'm using Launchpad Pro mk3. It has pad faders so I can control all these parameters. Pad faders are restrictive though and even with built in smoothing I can only set levels on specific values, between which the levels move smoothly.

Is the easiest way to do this with a boost converter IC?

I'm making a 4017/555 clock sequencer and have been intending to run it off it 9V. Issue is that if I want to take an external clock, those are typically 5V and that will not be enough to meet the threshold requirements of something running on 9V.

Yes, I could run the entire thing on 5V to get around this I suppose, but I kind of like the idea of doing 9V so that my CV range can be from 0-9V instead of 0-5V.

So, I figure, I could boost a 5V external clock to 9V somehow to allow the external clock signals to work.

Thoughts? What's the easiest way to increase the voltage of a clock signal?

I've designed a 10p front panel in KiCAD. No copper layers, only holes for pots, audio jacks, & mounting. I'd like it to have blue solder mask. PCBWay is having trouble with my soldermask layers. They say that "solder mask files are empty". They will not manufacture until I fix he problem.

I've done this before using JCLPCB to manufacture front panels. When I used JCLPCB, I kept all of the KiCAD settings at default values and JCLPCB manufactured perfectly. I look in the KiCAD settings. I see that I can specify no fewer than two copper layers. For the F. Mask & B. Mask layers, I can specify Material & Color, but I am not sure what to specify (my hunch is liquid ink). Slodermask color is selectable on the PCBWay order form, so that field seem immaterial.

Does anyone have experience ordering front panel "boards" from PCBWay? Thanks in advance.

Hey everyone! Just showing off my minimalist printed rack.
THe rails come from gie-tec and the printed side pannels come from here: https://www.thingiverse.com/thing:4923072
They are really nice give the designer some love!

https://preview.redd.it/z8k5i4dycige1.jpg?width=4032&format=pjpg&auto=webp&s=9f2f615d2571ecb27f8cffb9766558a4172e156d

https://preview.redd.it/140o33eycige1.jpg?width=4032&format=pjpg&auto=webp&s=c517df5bfb719385b3ea7cc620cb4d49eaa7f9ac

Hi there! I’m really interested in building a Radio Music module for my rack. I know the files are open source but printing them costs me like 90 dollars, and the Teensy 3.2 also isn’t cheap to find. Does anyone maybe have the PCB’s they want to sell on to a fellow DIYer? Located in Europe but also willing to pay shipping from USA.

Anybody know of some good polysynths to build? I dont mind between analog or digital, the few ive found out there just dont have a lot of documentation.

I noticed that Erica Synths released a device for saving one's patch routing for modular/semi-modular synths...looks like the matrix from their SYNTRX instruments. Basically four of those 8x8 LED matrixes arranged in a 2x2 grid with a microcontroller interface for saving your patch routing. I think calling it a 'Mixer' is a little less descriptive than 'Patching Matrix' or something, but it does offer a few attenuation levels and you can mix CVs with it.

Anyone have any ideas on what chip(s) they're using to handle the actual switching? Or are there some pics of the inside that show the chips hanging out somewhere that I haven't seen?

Or more generally - has anyone built something like this? If so, what ICs / what kind of setup did you use to handle the actual switching?

I've always figured that they're using one or more analog crosspoint matrix ICs; there are plenty of them out there. There are a handful that are DIP-types and could even be breadboarded, though I think that most are surface mount and would require a breakout board. Just interesting because I feel like a lot of synths with deep mod matrices are handling those signals digitally (or all of the pathways are just connected all the time and disabled as needed or have VCAs that are set to zero when not in use). Wondering how companies/people are handling switching of analog signals (if they are at all).

Just saw that they added an ability to save projects. Anyone considering making this device now has the option to save their work. A feature we've been looking forward to for years.

If anyone would like to buy a LMN-3 I have a special one for sale. Made by Floyd Steinberg himself.(upgraded with the help of his videos.) Dm me.

I am currently choosing components for my newly designed PCB.

My design features an input stage to my ADC and an output stage from my DAC.
I am attenuating 10Vpp input to 1.7Vpp, and vice versa on the output. so roughly a gain of 5
My input stage has a 1uF coupling cap. My output stage 10uF.
I am searching for the right dielectic material.
I heard MLCCs are really disadvised in audio applications because of piezoelectric effects.
Since this is my first design, i don't need to have hifi-top-notch-esoteric performance. It just needs to work and shouldnt sound like shat.

Can you recommend caps , that are usually used in Eurorack AC-coupling, preferably SMD?

I'm working on a Max4Live frontend for Ambika, and there's a couple parameters I can only reach through Sysex.

I have MIDI CC control: https://i.imgur.com/3qDCS5P.png

and I have NRPN control: https://i.imgur.com/rm1Bvpy.png

The parameters I can't reach are voice part allocation and BPM. I assume there is a message I can send to MIDI out that would set them, but I don't understand the instructions in the manual ( https://medias.audiofanzine.com/files/ambika-user-manual-mutable-instruments-476409.pdf ) for how to get that information. Could someone give me a hand? Happy to share the maxpat file, and I'll be posting it for free on maxforlive.com when it's finished

Pardon the naive beginner question but… Is it a worth replacing the tempco resistors if the leads have been cut? Building the MFOS sound lab mini synth mkii and realized after populating the pcb and cutting all the leads that rays instructions specify FULL LEADS on the tempcos that are in combination with the transistors. Again, thanks for indulging the novice.

Built default Minidexed as per the github using USB.

Works with controller but is not recognized by Mac or PC.

Last time I played with midi, it was an old MT32.

Thank you.

Hi guys, I don’t know if this is a stupid question or not, but I’d like some help to clear my doubts. I would like to build a basic 4 voices analog synth but I am a bit confused on how voices assignation works. For example, imagine I have already 4 keys pressed, how do I make sure that an eventual 5th keys pressed doesn’t play and doesn’t affect any voltage signal that is being sent to the oscillators? In wider terms, how do I connect every key to the 4 oscillators?

I received an Erica Synths Bassline pcb and panel for Christmas, which is awesome, but I'm having a hard time finding the LM337LZ/NOPB. It's obsolete and not on Digikey, Tayda, or Mouser. The only places that have it either have $100+ minimum order requirements or want $10-20 for it. They're listed on Amazon, but I don't trust them for anything I can't test quickly. Anyone know where to get this part or know of a substitute? Thanks!

I saw this post back in October:

https://www.reddit.com/r/arduino/comments/1fenu0y/midified_an_old_set_of_organ_bass_pedals_using_a/

Surprisingly, my brother and I had already made plans to get together the following weekend to do pretty much exactly what this fellow had done. I had a set of bass pedals from a Farfisa Compact combo organ, and was fortunate enough to have a parts organ as well from which I harvested the female pedal connector, then an Arduino, an Adafruit 7-seg display, some off-the-shelf parts and a project box, some programming time and voila! It's a lot cheaper than a new MIDI bass pedalboard and I can still use the pedals with the organ if I want to.

Here's the result:

https://youtu.be/K9BUOJILgAM

I'm making a synthesiser using a teensy 4.1 with the audio shield, it's powered using a lipo battery. I have a little speaker with a pam8403 amplifier.

When the teensy and the speaker are powered by different batteries, it works fine - the speaker plays the audio as expected.

However, when they're both connected to the same battery, the audio is very feeble and noisy.

I've read online before that a lot of people do use separate batteries for the speaker and the synthesiser - however, I've made a few synthesiser projects in the past - using the same teensy 4.1 and pam8403 amplifier. In the past, I've connected them both to the same battery and it's been fine.

So my question is, what might I be doing differently here, and how can I wrangle it to use the same battery for both?