AC/DC as FX when not connected to Computer

OWL AC/DC
#1

Hi. I have two AC/DC’s here but they are in sad state … unused since ages. The noise floor is just to high if used as an audio interface which I could never resolve and if in use I tend to use the AC/DC as input for the Scope Module in VCV Rack.

I try to find reasons to get the module back into my rack and wonder what it would take to patch the firmware in a way that the AC/DC could act as an patchable FX / Synth like the the Lich A) if not connected to the computer and B) if connected to the computer act like an audio interface?!

@antisvin I remember that you talked about a modified FW. Can you point me to where to find it?
@Befaco there is a lot of unused potential in this little module … I know I know, it is discontinued by now I guess for this exact reason.

#2

I had no idea that it got discontinued, but can’t say I’m entirely surprised by this.

I suspect it happened because there are some problems with hardware that would require redesign to fix (that noise issue, but there have been other problems with codec’s stability for some users, various OS-specific USB issues and more) as well as occasional firmware issues that are hard to understand. Unfortunately it doesn’t look like there’s going to be any updates from RebelTechnology any time soon, so it’s a niche module that would need lots of effort to maintain or would give very bad user experience to many buyers.

I think you’re asking about this post.

I try to find reasons to get the module back into my rack and wonder what it would take to patch the firmware in a way that the AC/DC could act as an patchable FX / Synth like the the Lich A) if not connected to the computer and B) if connected to the computer act like an audio interface?!

Right now it’s a compilation option, you have choose audio flow order between patch and USB when building firmware.

Regarding running patches, do you have some specific idea in mind? For me it seems like something ideal for quadraphonic audio processing (as a panner or 4 channel reverb). But most people don’t need that. Befaco never released the MIDI expander for adding more controls or connecting it to a keyboard with serial MIDI, so as a standalone unit with just 4 knobs it’s a bit limited right now.

#3

Ok, I take that back as I haven’t found any official statement … but at least the AC/DC is not listed on their products overview page anymore and my local shop (Schneiders Laden) has it listed as “This product is not available anymore.”.

Thank you for the link, that was the one I was searching for. Is was thinking to start simple, maybe transforming AC/DC into a four channel mixer / attenuator and later explore some ideas I have in mind. I would love to build a “write read buffer” like this or this for my Eurorack without the need to go through the Computer.

If I understood you right I have to choose (via FW flag) either between patch mode or having the module as an audio interface?! There would be no way to detect that on the FW side and switch to the according mode … at least not in its current incarnation, and there most probably never will be :thinking:

#4

Oh I didn’t say you’re wrong, just pointed out that I haven’t seen any announcements too. But I’m not sure that they normally announce this sort of things in first place.

Yeah I guess sampling could be an interesting application. You would have to control it with triggers sent to audio channels, but if stereo is sufficient, this would be good enough. Also, you’ll receive triggers at audio rate, not at block rate, which is important in this case. How familiar are you with writing patches and in which language?

Yes, exactly. Normally OWL sends audio input to USB device and USB input to patch. In this case we want to send audio input to patch and patch output to USB. And the same inversion is needed for output.

Doing it automatically is not ideal - it would mean that your patch stops working if you plug the USB cable. So ideally user would be able to toggles this with a switch if necessary. However, AC/DC is so minimalistic in terms of controls, that I guess anyone running a custom patch would just have one for some specific purpose.

#5

I know some PD, dabbled with Faust a little and in general know C/C++ … but i have no experience regarding the OWL platform so far except my various attempt flashing a new FW.

I guess I could live with that :wink: Anyway more important for now is to get the FW compiled and flashed … had some issues with that last time and almost brigged the module.

#6

Well with PD on OWL you compile the patch with Heavy compiler which is not 100% compliant with desktop version and may require some workarounds in certain cases.

FAUST is pretty well supported, you can generally compile the same patch for desktop without any issues. You would have to use my branch for running FAUST patches on AC/DC as there are a few fixes that upstream OwlProgram doesn’t have and upstream only works on some older version of FAUST due to changes to memory management. It probably should be your first choice here.

For C++ there’s a fairly steep learning curve for how things are done in OwlProgram libraries and what your patch is supposed to do. It’s possible to build a desktop version of C++ patches, but it’s not very easy to integrate it in other software (but possible, i.e. Oneiroi patch was ported to VCV rack and you can convert any patch if you spend enough time on that)

1 Like
#7

For the time being I borrowed a Befaco Lich from a friend … I will try there before I give the AC/DC another go. Thanks for you detailed answer!

I will report back when/if there is success in sight :slight_smile: