AC/DC MIDI input

I’m interested in using the AC/DC for hosting OWL patches for quadraphonic audio. Since I’ll be using all four inputs for audio, I’ll need MIDI input for control. Is there any way in Eurorack to get MIDI into the AC/DC (without going out to a PC or iPad)?

Maybe @Befaco can chime in?

AC/DC is not ideal for this as it only has an USB device port, so you’ll need a controller that has a USB host which is not that common. There is an extra header on it that might be used for serial MIDI IO if there would be some sort of expander made. But I did run a few quadraphonic patches written in FAUST on AC/DC, I think it also required a custom firmware build to change USB audio routing.

Currently I’m working on C++ versions of that code with somewhat different algorithms. Some optimizations are required as I want to have at least a panner and a FDN reverb running on it.

Those sound interesting. What’s your plan for controlling those algorithms?

I’d love it if Befaco did an expander for AC/DC with a few CV controls and a MIDI input. Would make for a great quadraphonic DSP module (in much less HP than the Daisy Patch).

The Lich has a USB host port… maybe it could provide some control to the AC/DC?

For the time being, I’m running this stuff on a Daisy Patch myself with serial MIDI connection from Polyend Tracker. Using 2 devices seems unreasonable to me, considering that you end up with almost the same HP and lose the display. Plus there’s extra latency from adding an intermediate device.

I agree that an expander for serial MIDI jacks in 2HP would be very convenient for using it for patches rather than as an audio interface.

I will spend some time in eagle drawing a simple solution. Don’t expect it too soon, but I will get int it!

1 Like

Hopefuly it fits in 2HP! Something to consider about this hypothetical expander:

  • the expander header on OWL board is providing ground and UART RX/TX connections, but no power, so it would likely have to be taken from the eurorack power header.
  • serial MIDI is not enabled in firmware for devices don’t have it, so we’ll have to wait for a new release that adds code to initialize UART. But it’s not hard to hack a custom firmware version that adds it

If we do it SMD definetly 2 HP is possible. Will keep u posted on this one

Most 2 HP modules are connecting PCB under right angle to the panel rather than parallel, so SMD is not a strict requirement unless there’s too many components to fit in reasonable depth. There are angled stereo jacks which could be used in this case to connect front panel with PCB:

And as a reminder, it might be beneficial to add jumpers to change TRS wiring for using with both type A and B cables.

Hi, layman here. Does anyone know if it’s possible to connect the midi pins on the back to another midi device such as an f8r by Michigan synth works, which also has pins for midi. I would like to be able to send midi cc data from the faders to the computer over the ac/dc’s connection. Can’t seem to find any information on this anywhere.

Serial MIDI is not initialized in current ACDC firmware, but likely would be in the next firmware release along with official MIDI expander.

Note that the device you’ve mentioned exposes MIDI header with wiring to be connected to a MIDI cable, while ACDC only exposes its UART port and you must the upcoming expander or something equivalent. So you would either have to connect two UART together bypassing all the normal MIDI circuitry that isolates devices normally or connect both devices via cable (i.e. use OWL expander and some “dumb” expander that just adds jacks for f8r header)

Any news on the upcoming expander? Anxious to get my hands on it so I can build some quadraphonic patches for AC/DC

Actually there are some news, Manu made a prototype PCB/panel for this and I have a few of them. It’s fairly simple, but SMD soldering is necessary (0603 size). I’ve missed a few components needed to build it, will buy extra parts next week. If all goes well, I’ll try to get it work with a few modules that I have (AC/DC, Lich).

1 Like

Any news on the MIDI expander? I imagine if it made use of the JST connector it could also work on Lich? :thinking:

Yes, it’s intended to be used with Lich too, although this would require a new firmware release. The latest news is that Manu confirmed that it works (well, after finding a few minor mistakes on PCB).

1 Like