Modules for DIY in Eurorack use 3.5mm mono jacks that come in three basic types, each with a different PCB footprint. The part numbers for each of these is different from different manufacturers and also have changed over time. I’m writing this post for my own benefit as well as anyone who has ever been confused by the proliferation of part numbers.
Thonkiconn
Thonkiconn jacks are named for the DIY seller Thonk.
WQP-518MA, previously PJ301M-12, previously WQP-PJ398SM
WQP-518MA are the newest version from Qingpu Electronics featuring a square bushing plate for added durability.
Erthenvar or snap-in (BM suffix)
The WQP-518MA-BM is the new improved version of the WQP-PJ301BM, previously WQP-PJ398S-BM, featuring Qingpu’s rugged square based bushing. The sleeve connection is through the outer bracket that snaps into place on the PCB allowing for easy construction and panel fitting. This type of jack is used in Befaco modules.
Kobiconn
Kobiconn jacks are used by nonlinearcircuits and others. They are easily identified by three lugs, one of which flies above the PCB.
Doepfer type jack
Some Eurorack modules use yet another type of jack.
PJ324 stereo jack
Added by request, but it’s not typical for Eurorack builds.
Even more types!
There are many types of 3.5mm jack available. I can’t list all of them of course. This post is for the typical Eurorack DIY builder.
Great and Beneficial Post!
Thanks, Josh. It was a bit of work finding those photos!
Thanks for the summary. Bookmarked.
You might want to include the PJ-324, which are used in quite some modules to mount the PCBs orthogonally to the panel to save space.
Hi Joe. All the PJ324 jacks I found were stereo jacks, like the one I added. Do you have a link to a DIY module that uses these?
Michael Zülch uses these for example in his 2hp Slim Line modules. https://github.com/mzuelch/CATs-Eurosynth
Great post, very helpful! I recently had a great DIY lo-pass gate build throw me because the part numbers PJ-301BM and PJ-3001F look so similar that I assumed they were both Thonkiconn style/footprint/sizing. They are not! It looks like they all have strengths and weaknesses, I’m feeling that replicating the wonderful construction quality of Befaco would be ideal so I’ll try the WQP-518MA-BM aka WQP-PJ301BM, aka WQP-PJ398S-BM soon!