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Thanks, the HP output is designed for headphones 80-250 ohm impedance, but you can use them with 32 ohm headphones, you just need to be careful not to turn up the volume to high (or you can adjust the gain of the headphone volume control by changing a couple of resistors)

@MeeBilt Thank you, I'll give it a go!

Hey, thanks a lot!

Thanks a lot! I did it like this: 1) I took dimensions from the datasheets for the components to locate all the holes 2) after that I made the design of the main PCB in KiCad placing out the components on the PCB the way I wanted them. In some cases I had to download 3D-models of the components from the suppliers and add them to my component library. 3) I exported the PCB design as an STEP-file 4) then I imported the design into Freecad and designed the enclosure around the PCB 3D-model 5) next step was to design the outline of the front- and back-panels in KiCad. 6) I used the top surface of the main PCB as the reference plane and then I placed all the holes for the connectors and pots using the measurements from step 1) above. 7) final step was to verify the location by exporting STEP files for the panels and bring them into FreeCad so I could check that everything matched up before I sent the PCBs for manufacturing

@@MeeBilt wow amazing, this would help me so much! Thank you so much sir. in future if you have the time and motivation could you make a video of you explaining the process of you doing the mechanical work for your products, such as mechanical design decisions and techniques. Thank you once again!

I have a series of episodes called "909 Rimshot" on my channel that explains my workflow. It's for a Eurorack module, but I basically used the same method for this design. In order to fit the holes for connectors and pots I used 3D-models of the PCBs that I exported from KiCad into FreeCad where I checked the aligment and dimensions. I hope this answers your question

This is not a problem that I have experienced. But I guess that it would be possible to make an in-situ tuning in the preferred listening position and adjust groupdelay of the front speakers to match the subwoofer response.

I think the point of active crossovers is you can design them to avoid the phase shift of a purely passive crossover. If you’re really bothered about time and phase alignment, get a multi channel amp with DSP, then you can time align based on where the drivers are positioned in relation to your listening position.

Unfortunately I don't have access to an audioanalyser, but my plan is to buy one. I'm also curious how the circuit performs and if I can make any improvements to it.

Thanks a lot!

Thanks and happy new year!

There will be a couple of videos about this project early next year

Me too... that's why I'm finally decided to build one

You can use the bmult-top-cpl instead

@@MeeBilt yes, I checked everything and did not find a file named top. Maybe I'm wrong. Please help me find it.

The firmware was pre-programmed in the STM32 so I didn't have to flash it myself. The module supports Mutable Instruments original firmware, so you could use that I guess: pichenettes.github.io/mutable-instruments-documentation/modules/plaits/firmware/

Yeah, it requires a bit of filtering. The PCB that I made took care of most of the interference, but the toroid inductors can be difficult to get hold of.

Sorry to hear that you have issues with the build. My suggestion is to start by double-checking the component placement, especially the diodes, since they very easy to mount the wrong way around. One thing that is very important with the trigger input is a good square-wave with a fast transition is used, since the trigger pulse is derived from that. This is valid for all 909 modules. A slow rise time will not work.

Thanks!

I'm sorry I can't help you with that. It could be the LCD screen itself or the conductive rubber that connects between the LCD glass and the PCB that is damaged.

Hey, welcome to the world of Eurorack 😀 First of all you will need a good power supply that can output regulated +12VDC and -12VDC to power your module. Next you need consider what signal levels you can input to the module and what signal levels you get out of the module. In general Eurorack modules have a input signal range of +/- 5 VDC and the same levels are outputted from the module. These are quite high signal levels compared instrument or line levels, the safe (but more costly) option would be to connect an input module and an output module with the filter in between. But you could probably get some kind of LP filtering going by just inputting line levels directly into the filter and sending the output from the filter to the next unit in the signal chain.

The knobs will act as faders, but keep in mind that the middle position is "0" (max attenuation) and the full CW is max level. Turning the knob to full CCW will also give max level, but with the signal is 180 degrees phase-shifted(!) I don't have any audio mixer in my Eurorack case (yet), so I use an Utility Mixer for this purpose, but it is a bit awkward to use when you need to bring down a level to 0 in a mix.

I would suggest to use a triangle waveform as a CV signal when you are testing. A square wave isn't really gonna help you troubleshoot the exp output - it's better to use a linear waveform like a triangle (or a sawtooth). Keep in mind that the control input on the OTA is a current input and if you exceed ~2 mA the chip will break down. Measuring the current on the exp output is also a bit tricky, especially if you measure the voltage levels and have the OTA connected, but I guess that you could measure across the 20k resistor with a multimeter and calculate the current. Finally; building this circuit on a breadboard (or stripboard) is really difficult. The LM13700 operates with really small signal levels and I barely got it to work on my breadboard setup. I didn't get good performance until I made the PCB.

@@MeeBilt Thank you so much!! I finally replaced the transistors with other units of the same specification and got it working. Thanks for the advice! Now it's time to design a decent board. I could barely fit all the components on a 10 HP panel since I did it with two CV inputs per channel. I just started building my own modular synth a month ago, and your channel is helping me a lot. Once again thanks for your work.

@@oscarpastor4439 Awesome, welcome to the fun world of Synthy DIY. Good luck with your builds!

I haven't tried that myself, but it probably works fine too, I would imagine.

The hex nut on the pots fits a standard 10mm hexagon socket that you can find in any tool/hardware store. The tool for the knurled nuts were bought at Thonk (www.thonk.co.uk/shop/thonk-knurled-nut-driver/)

Thanks

I think that there are BAV99 clamping diodes on all inputs and outputs. dl.modulove.de/module/arythmatik/ibom.html

I have actually tried this but I could not get the needed strength and precision. Discussed it a lot with the manufacturet, but they could not help me. But I will keep on searching.

@@MeeBilt the other option is antistatic spray.

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Thanks a lot for the nice words. I'm happy that you find it useful!

it the diode clipping mod from the neinohnein documentation