New Lurker - looking at Zynthian V4

hey folks, new user Scott here, greeting you from the wilds of the West Coast of the US where there are still a few things that are not on fire, surprisingly…

anyway i didn’t see a general category or an area for questions about usability. i’ve been lurking the forums for a while and balking at springing for the full V4 kit, but last night i looked at the completed build thread and i got excited because there seem to be lots of users doing their own thing at every conceivable sophistication level from plastic food containers up to fully CNC machined aluminum enclosures. so i feel pretty good about starting out with a basic box with a few V4 components and then upgrading later.

here’s my use case. this is going to be part of a live performance setup using a Pure Data patch with virtual instruments and effects, currently running on macOS. all of these are done via vanilla PureData with a few external libraries. control of this will be via direct ethernet connection to a second computer running the interface and sending OSC messages only - no direct connection to the Zynthian via I2C, etc.

the MIDI input will be over USB via a basic connection, again, routed to PD. i will only need one channel for this really. i may use DIN connections later on.

audio will be handled by a cheap USB C-Media dongle. it seems these have pretty good Linux support.

so here’s my questions before getting on this crazy train and i’m just confirming if these are possible:

OSC data over Ethernet to Pi via a point to point network? do i perhaps have to open the firewall of the Zynthian in that case? sort of like ssh but with data.

MIDI over USB on Pi? seems like it’s possible via the webconfig based on what @jofemodo has stated previously.

Audio over USB interface into Pi (cheap dongle running C-Media chipset)?

does anyone know what the outer dimensions of the ZynScreen 1.5 are? would be very helpful for me to determine a temporary case…

along a similar line - if i’m NOT using the HiFiBerry for audio in/out and not running the DIN MIDI, can i run a single 40 pin ribbon cable between the Pi and the screen and not use the Zynaptic module at all?

my plan is to buy the Pi, SD card, power supply and ribbon over here, and the encoders and screen from the store. trying to avoid soldering if possible - i did read about directly wiring to the Pi from the encoders, but that seemed really kludgy and the extra three caps on each via the PCB is supposed to increase reliability.

anyway answers to some or all of these questions would be very appreciated!

best to all!

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Welcome to the community @metaphysician. Having lurked for a while you will already know what a great bunch of enthusiasts are here.

There is no firewall on the Zynthian blocking OSC. The Zynthian listens for OSC over UDP/IP on port 1370. It has a limited amount of OSC support and does not (yet) support feedback of values (something I have been working on though). You can perform a range of actions via OSC to control the Zynthian. @ronsum and I have been working on an OSC Android client which we will share soon. (Spoilers!)

C-media audio works fine although the sound quality of some of the (very) cheap interfaces is variable. I have a couple and they sound fine one day then seem to inexplicably deteriorate on other days! You could use the Raspberry Pi’s built in 3.5mm (1/8") stereo audio output, at least for initial tests which although not perfect, isn’t bad and is consistent. Maybe your C-media interfaces aren’t as cheap as mine.

Class compliant USB MIDI interfaces are supported which covers a lot of them. A few others are also supported such as the MIDISport which uses extra firmware which is installed on the Zynthian by default. If a MIDI interface says it works on Mac and Windows without drivers then it is likely to be class compliant and hence work on Zynthian.

I have a breakout board which I designed and built myself which has screen, audio, MIDI, power-on button, etc. This is connected to the Raspberry Pi via a 40 pin IDC connector and cable (from an old IDE drive). As I develop bits I add or remove use of various pins, e.g. I am no longer using it to drive a screen. If you don’t need I2C, I2S, switches, etc. then you can connect a cable to the header that spans all pins. You can always add an intermediate breakout later if required.

My experience has been that my very customised unit benefited from deviating from the standard kit but generally you will get best support using standard build and parts from the shop and it tends to cost no more than buying parts then buying other parts to get things working. (Many people (me included) enjoy the challenge.) Buying from the shop also supports the project.

By far the most useful advice is to buy a good quality PSU with good quality cable. Failure to do so (often by accident due to variable quality sellers) is probably the most frequent cause of problems. I recommend buying the official Raspberry Pi PSU. It is reasonably priced and is guaranteed to work.

You can get a Zynthian working with just:

  • Raspberry Pi 4 (any model)
  • PSU
  • uSD card (16GB or larger)
  • micro HDMI cable (to whatever connector is on your monitor)
  • Ethernet cable
  • 3.5mm audio cable / headphones

You can lose the HDMI and use X-forwarding over SSH if you want but this is straying into the realms of geekdom, requiring a few, less supported skills. I have done this with an Android tablet / phone as display and also regularly show display on my laptop whilst developing.

Sorry, I don’t have an official screen for dimensions.

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thanks for the warm welcome!

that’s some excellent information to know - it fills in a lot of gaps i had about how budget i could go in setting the platform up. i’m first interested to see its viability as a live performance PD instrument as stable as those Muse Research Receptor modules. that may be a high bar to hit, but my stuff would require half doing synthesis DSP and half sampled playback manipulation. i don’t know if Rpi 4 4GB can handle it, but i know the hardware gets more and more powerful and i’ve heard good things about the 4.

so, i have a few questions on some usability and how you can code on the OS, but let me skip to an obvious one. do i need to get a fan for the Pi in the meantime before i get a case or enclosure together. does it really need a fan at all? heard various things but nothing really conclusive. i know folks who purchased the v4 case probably don’t have issues since the case functions as a heat dissipator, but i see a few examples of Zynths that are pretty unconventional, so i’m curious if those builders are using fans.

anyway, thanks again for the excellent information. looks like i’ll be doing the bare minimum Zynth due to some unexpected extra expenses. looking forward to more interactions!


A fan is not really needed but some method of dissipating the heat is recommended. You want to avoid thermal throttling and driving the CPU hard (like it sound you intend to) can trigger this fairly quickly. First consider how you are going dissipate the heat from the CPU. You may wish to attach a large heatsink. The V4 uses its aluminium case for this purpose. Next you want to consider how to get rid of that disapated heat! It’s no use adding a heatsink if the ambient temperature build up within the enclosure. (Heatsinks work by conducting heat from high to low temperature.) This could be done with vents in the case or making the heatsink external / part of the case. You could add a fan to the heatsink or somewhere else to extract the hot air. I have a full size heatsink with attached fan. Which works well but I don’t currently have the fan wired, pending me building a controller circuit to turn on and control speed only as required. I want a mostly silent Zynthian which may ramp up a fan in hostile environments such as a hot rehearsal room or gig where hopefully it is too noisy to hear due to other musicians making a row.

In the zynthian-hw repository you have the Zynscreen design files, including meassurements.


hi @jofemodo - i’m looking at that section but assuming i only have apps which can read PDFs or SVGs i’m not seeing anything here with the outer dimensions and physical layout of the board. i see kicaid files and such but the PDF and SVG only show the schematics. if there something i can open (text docs are fine too) with measurement dimensions, let me know because it doesn’t seem obvious to me. thanks!