The EuroPi is a neat multi-functional eurorack module by Allen Synthesis, based on the Raspberry Pi Pico (and soon to be even better with Pico 2 support which should make it feel snappier !).
When I started sourcing parts to build one, I found that the OLED modules and buttons in the original design were a little more expensive for me to acquire in Australia, compared with the more common Ali Express versions. I also really wanted the design in KiCad. I reworked the EuroPi hardware to use these alternative OLED variants and cheaper tactile buttons. I also moved around some buttons and jacks to my own preferences (making it more like the uO_C Ornament and Crime layout).
This is the result - the screen is slightly offset to the left (which I'm guessing is why Rory Allen's original design may have used less common OLED modules), so I've tried to maintain symmetry by 'filling in' the asymmetrical part with the silkscreen on the panel. I think it works okay (it's not triggering any OCD in me anyway !).
... another thing added to the to-build wish list :)
He always makes it look so easy !
I think this highlighted to me that I've made breadboarding harder than it should be by using crappy pre-made breadboarding wires that tend to break off after a few bends. Much better to get some good wire strippers and solid core wire like Sam uses here.
I think I need to brush up on my Soviet IC codes - I found this, https://elcomps.com/en/a76 from which I can decipher that there are some analogue switch ICs (K157 ?) and maybe some NANDs (K155 ?), but I'd love a big list of codes and the closest Western CMOS equivalent to help understand these.
A little more experimentation and I've found the ADSR envelope stays almost flat with all sliders down if it's triggered via a 5V gate to the Gate input. There is still the tiniest bump when triggered this way, but nothing close to the effect of the manual gate button. Triggering via MIDI seems to behave more like pressing the manual gate button.
The other interesting thing I discovered is that the LFO 'leaks' into the VCO1 FM mod, even with the vibrato depth and LFO FM mod on VCO1 all the way down. The solution is to plug a dummy patch cable into the "Ext Vib In" input. This seems to break the normalling of the LFO in the right place to prevent this leakage (plugging a dummy cable into LFO FM mod on VCO1 didn't work, which must say something about the signal path the LFO is taking to leak into the VCO1 freq modulation).
One thing I've noticed about the 2600 (and I doubt this is unique to the BARP clone) is there are a lot of signal paths that aren't buffered or isolated like you might expect in a heavily engineered Eurorack module or modern semi-modular. Sometimes it provides interesting character, other times it shows the compromises of it's age and feels a bit broken by modern expectations.
I tested this on my Behringer 2600 and got similar behaviour, so I suspect it's a quirk if the hardware, (one that is possibly not emulated by the Arturia VST). One way around it seems to be to patch a gate into the ADSR gate input instead of using the manual trigger button - try patching the internal sample and hold clock into the ADSR gate input, and the envelope stays flat until you raise some of the sliders.
I wonder if it happens when you trigger via MIDI ? (I didn't test) Patching the KBD gate or trigger from the left hand side into the ADSR would be an option to try too.
For me it's more nostalgia, since I remember playing the game as a kid and the music was bold and iconic (and part Moonlight Sonata). It's funny though, in my memory it sounded more complex, not just a single square-wave tone. I wonder if there was an AdLib/AWE32/SoundBlaster version that played on my PC.
Roucha Legio looks interesting - a good balance of features in a fairly small space. I'd sort of stopped paying attention to all the new Legio modules, but with so many options now, the ability to just swap the firmware to try one out is becoming pretty compelling.
I would suggest as a starting point maybe just start using the FX Aid XL and Morphagene with your current gear, make some sounds and start to find what's missing. When you think ... "I've really love to be able to ... or "I would really like to tweak this VCV rack module in hardware", then find a module to help fill that function. This will give you time to learn and master the new things you have before adding more.
RE Ochd vs Maths - even though it's a bigger footprint for less LFOs, I feel like you might have fun with all the interesting generative feedback type patches you can do with Maths given the style you are aiming for. It can even be an extra (non-V/Oct) VCO for drones. Maths does take a bit of time to learn and understand. Another interesting module in this space (which I don't have but very much want) would be the After Later QARV. Or Pams New Workout - lots of modulation options beyond simple LFOs, but not everyone's cup'o'tea since it has a screen and some non-divey menus.
No specific suggestions for a filter, but it makes sense to have one given your existing gear. If you are going for a stereo signal path, I'd suggest a stereo filter since you can get some great spatial effects by modulating channels independently.
With regard to Befaco Out, it could be worth looking at small stereo mixers as an alternative, especially one that lets you attenuate the master output level, since this could go straight into your line-level speakers/computer.
Thought I'd repost this from !oldweb@lemmy.ml - an oldie but still a goodie, and an amazing legacy for the SynthDIY community.
Thanks for the tip. The official Reddit app is a hot mess and I'm not sure patching out the ads will fix it enough.
Agree, too early to tell how it will pan out. It might allow Moog to compete with the Behringer clones on price by scaling up some non-US manufacturing. I hope they keep the US manufacturing arm too, even if it's only for more the boutique or expensive models (that I'll likely never own, but like the idea that they exist !).
That's what I've been up to over the New Year - trying to properly finish off a few 90% done things and share them if they are useful.