Faderbank Run: See top post for status

I did a version of this for myself using a low-profile Switchcraft 3.5mm jack I purchased on Mouser. I added in some pull-up so I can drive my TELEX expanders directly from it. Now that we have busboards and the like, I’ll most likely do a revision and remove the pull-up. I’d be happy to contribute some energy in this and also in the Teletype operators if needed. :slight_smile:


that’s an option too and saves on having to implement TWI but the benefit of going with TWI route is that you could use faderbank/keyboard or faderbank/grid at the same time.

alternatively a faderbank mode could be added to ansible perhaps with its own remotes?

@bpcmusic that looks awesome! i’d be happy to help with the firmware side of things too.


Throwing my hat in the ring for a kit or built!

Very much interested in a built unit. Thanks!

I’d be interested in a built unit and maybe a kit. :cactus:

I see a lot of people requesting built units: happy to help assemble and send for people in EU to cut cost, but as long if I don’t have to do the sourcing and deal with customs (send and receive) :slight_smile:


I’m interested in a built unit too

Can get rid of the HUGE Kenton Control Freak SE :slight_smile:


Interested too in a built unit or kit, depending on the shipping etc (EU)

Interested, but not sure if i understood : will it have a hardware MIDI Out ?

“Maybe”. The original design (that @shellfritsch has) doesn’t have a hardware MIDI out.

However, two modifications are being posited to this design:

  • I am positing adding a hardware MIDI out that simply duplicates the USB out. It would be a 3.5mm TRS minijack (sorry) with a switch to swap between the two 3.5mm TRS standards, best explained as ‘Arturia/Novation’ (tip is current source) and ‘Korg’ (ring is current source). This modification requires three extra parts - two resistors and a jack socket - and some code changes (as the Teensy MIDI library points out, USB Midi and UART midi can be used simulatneously). It is a straightforward change, and easily customisable (to eg spit out MIDI on a different channel or different CCs to the USB port).
  • Pin headers will be added to the board to break out “TWI” (aka I2C or II). From the discussion above, these will be bare pinheaders that many users can ignore, and I2C hackers can put to use. Given the shape of the board, I might suggest making them right-angled headers (so that any cables added don’t interfere with the low height of the unit).

So - if you’re specifically interested in hardware MIDI out, that’s at least another voice validating that decision IMHO. But I’m going to infer from @shellfritsch that the goal is to make a short run with minimal extra complications!


Did some quick research into PCB costings - bear in mind that this isn’t my project, but was trying to wrap my head around the sums. Prototype-boards from OSHpark have cost $196 for 3, so about $65 a board. I ran the dimensions through Eurocircuits (who I use, and I’d class as a ‘not super cheap but nice quality’ manufacturer - much better quality boards than some of the ultra-cheap Chinese suppliers I’ve used). Including VAT, Eurocircuits cost the boards as around $25 each for a run of 25, and about $20 each as the run gets nearer to 50.

Just throwing that out there for reference.

Thanks, i was asking for two reasons :

  1. i don’t know why but i always assumed that Teensy could only pass MIDI thru USB.
  2. hardware MIDI is essential so i’m definitely interested.

So, quick sketching:

Pin 12 of the Teensy is used for MIDI Out (that’s up for grabs), I2C broken out, switch to toggle standards, labelling on the PCB.

The obvious thing that is wrong here is that I’d rather the jack connector and II connector were on the far right edge, pointing out sideways. The reason I haven’t put them there is that I think I need EAGLE Premium to be able to do so - like, the board doesn’t fit into the 160cm^2 limit of even EAGLE Standard. SIgh.

i’d suggest a 5v and gnd header along with the scl/sda. otherwise powering it separately isn’t quite the same value proposition (two cables).

has anyone made a usb-to-3.5mm midi dongle/cable?

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good point. easily added; also, the II lines should probably have dedicated pull-ups on to be on the safe-side. Like I said, just sketching.

Would definitely be interested in a kit if pcb price was closer to the Eurocircuits one that @infovore mentioned!

Please don’t take that as anything other than me prodding PCB costs from one German manufacturer. If they’re doing a short run, the boards will not be as expensive as the one-off OSH protos. Bear in mind that a decent chunk of kit costs will be the faders, I’d imagine.

Tentatively interested, subject to a little more detail on cost. EU built unit would be v. nice!


Also knowing if 3.5mm TWI jack is included will be an important factor

I would recommend avoiding bare pins for the ii/i2c/TWI. As this device isn’t mounted in a rack with the cables hidden behind, it would be way too easy to dislodge the cable when in use. This is why, after looking for options, I went ahead and adopted the Aleph’s 3.5mm “standard” with my remix beta unit. :slight_smile:

Not so sure here either. Both Teletype and the Aleph have pull-ups, which we can augment with the busboards. I’ve been lamenting putting pull-ups on by beta unit as it seems to limit its use in those scenarios.