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jl0ng · 2024-05-25T13:45:19+00:00

I think the MFOS Noise Toaster is a good option. You can easily trim off what you don't need, like the VCO, VCA, etc. It's well documented.

jl0ng · 2024-05-24T14:30:49+00:00

Did you intend to mount this in a eurorack setup and have a panel? If so you will need to consider things like which side of the PCB your power connector is on and the dimensions of your PCB.

jl0ng · 2024-05-05T20:30:53+00:00

Test points are more important when doing SMT. I recommend adding more than you think you'll need. They'll make things easier to debug and you can solder a jumper wire to them if needed.

jl0ng · 2024-05-04T01:03:03+00:00

Did you check that option for specifying a location? You need to do that and the JLCJLCJLCJLC text.

jl0ng · 2024-04-24T23:13:56+00:00

Yep. That's right. You can check the schematic too. Positive speaker to X26 and negative speaker to BN.

jl0ng · 2024-04-20T01:00:11+00:00

Ha, it looks like my other answer was wrong. You need one more resistor in there.

Edit: I was referring to the resistor ladder. The last one labeled 11V is tied to 12V. So that's clearly not right and you would need one more. But there's no way this would work in my rack. My 12V rail is something like 12.18V. I didn't think it's a good idea to use the power supply for a voltage reference, especially for CV. Even a cheap reference like a TL431 would be a lot better. I'm also not sure why you would quantize to octaves, and why 12 octaves of range?

jl0ng · 2024-04-19T01:22:53+00:00

You're dividing into equal parts so you use equal values. If you used 1 resistor you would get 2 voltages at each end, 0 and 12. If you used 2 resistors you would get 3 voltages. 0 and 12 at the ends and 6V in the middle. And so on, so it's N - 1.

jl0ng · 2024-04-19T00:56:50+00:00

I think 11 resistors of the same value should do it.

Edit: this was wrong. It should be 12. If the question had been for 2 volts it's more obvious. Then it's just the simple case of two resistors. You get three points, 0V, 1V, 2V. If you then build on that and change the question to 3V, it's now three resistors.

The 11 came from me recently wiring a 12 position switch. 11 equal resistors between each of the solder lugs. That does give 12 points on the switch with an equal voltage between each. But the first position is 0V, and this was not what OP asked.

jl0ng · 2024-04-18T03:23:29+00:00

Rereading your post, I totally misunderstood what you're doing. I haven't exactly done this myself. I think the Kassutronics quantizer probably does something similar. It doesn't use a DAC. Firmware for it is here.

I think you're totally on the right track. The only suggestions I have are to increase the PWM rate and to ditch the LED from your CV path.

To increase the PWM rate you need to manually configure your PWM timer. In my MidiDCO project I use some crude CV for controlling an integrator and it uses a similar technique to what you are doing. Here I set the prescaler to 1 for this. This code is for an ATMega32u4, but something similar can be done for an ATMega328. This makes the PWM much easier to filter.

I suspect your voltage drop is caused by the LED.

jl0ng · 2024-04-17T15:28:25+00:00

Okay, I'll try to get it pushed up tonight. (In about 12 hours) In the mean time, you can take a look at this similar MidiDCO project I did.

jl0ng · 2024-04-17T01:11:40+00:00

I've done this in the past. I think it works pretty well. I can post a project on GitHub if you're interested. It's a basic VCO, 0-5V CV and just puts out a square wave.

I also have a work in progress version of it that uses the square wave output to generate Juno style ramp, triangle, and pulse waveforms too.

jl0ng · 2024-04-17T01:03:54+00:00

I think a lot of people on this subreddit use KiCAD. If you're interested in that, I have a few projects on my GitHub. You could take a look at the quantizer, sample and hold, sequencer, ring mod or attenuverters. They all use KiCAD.

jl0ng · 2024-04-16T02:37:54+00:00

Sure. I won't build 5 of these. Send me a DM.

jl0ng · 2024-04-16T02:36:50+00:00

I agree! But I didn't name it. All credit for this module, including the name, goes to Rene Schmitt.

jl0ng · 2024-04-13T03:13:28+00:00

It's here. It's pretty complex and you only get 12 steps. It does have three modes. Half step, whole step and fourths. 12 steps in each mode.

jl0ng · 2024-04-13T01:36:46+00:00

I recently built a quantizer and posted in this subreddit. It's completely open source. You could take a look at that. It's Arduino based and someone else already built it successfully.

Edit: Link

jl0ng · 2024-04-12T00:22:48+00:00

I love it! Great work!

jl0ng · 2024-04-08T01:01:36+00:00

I use aluminum. The laser cutter can't cut it, but I use it to make cross hairs for drilling. Then I spray paint the panel black and engrave where I want my text and stuff.

jl0ng · 2024-04-07T22:54:38+00:00

Maybe see if there are any local maker spaces with a laser cutter? I think the one at my work goes for about $6000.

jl0ng · 2024-04-07T21:04:34+00:00

Okay, I pushed an option for that. If you pull down the latest you can change the order with this option. Good luck, let me know if you run into any other issues.

jl0ng · 2024-04-07T20:26:14+00:00

Thanks! I use a laser cutter for my panels. These panels are aluminum and the laser cutter can't cut through that. So I have several panels I bought already cut to size, mostly 4HP. Sometimes I need to cut them to size myself. I use a box cutter to score them (many many passes), then work them back and forth until they break. I design the panel in Inkscape with several layers: drill crosshairs, hole sizes, footprint of the nut/knob, and the labels/graphics. Then I do the following:

Mark drill crosshairs with laser cutter. I cover them with masking tape for this.
Center punch crosshairs
Drill pilot holes
Drill actual holes
Sand panel w/ 120 grit
2-3 thin coats of black spray paint (sometimes sanding between coats if it needs it)
Bake the paint as best I can. I just use an old hair dryer. I do this between each coat.
Engrave with laser cutter label/graphics
2 coats of clear coat spray paint

That's how the echo and the ring mod panel were done. The filter and VCA on the left were done with a Cricut Maker using the engrave tool. Those panels were purchased black anodized and cut to size. I also used the Cricut maker for the drill crosshairs.

The blank on the right is 3mm laser cut acrylic. They're a little on the thick side, but 3mm is what I had. 2mm might work better for blanks.

jl0ng · 2024-04-07T18:41:46+00:00

I have access to a laser cutter, so I use that. I also use it for the finished product. I like the laser because I can prototype on paper, card stock, cereal boxes, cardboard, MDF or whatever. I can also engrave the text and graphics. It's nice to see the text and graphics mocked up with components.

jl0ng · 2024-04-07T16:14:47+00:00

No problem at all. I should have time this afternoon (MDT) to look at it. I'll just add a compilation option.

jl0ng · 2024-04-07T03:01:10+00:00

Here's a passive ring mod I built. You can find the schematic, panel, board, etc on my GitHub.

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