I recently got myself a Doepfer Dark Energy and thought I'd let you share in my findings, as I'm very enthusiastic about this little bit of synthesizer magic!
The Dark Energy (I'll call it DE from now on) is a monophonic, 100% analog synth. The only digital bit in it is a usb interface for connecting it to a pc, but you can also input a normal midi cable. It's surprisingly small - especially when you consider the amount of knobs and switches on it. Having said that, the layout is very clear and despite the amount of controls never feels cluttered once you played a bit with it. What I like is the quality. It's built very sturdily and all the connectors and knobs and switches feel great and are connected to the outer casing so there's no wobbly pots or such.
Though the DE only has one oscillator, you can set this to either saw or triangle and you can mix to that a pulse that can be adjusted in width. The filter can be driven into self oscillation and can really add some nice filter weirdness to the sound. There are two LFO's that can be driven into nearly audio range and an ENV that can be set to snappy, medium or long which is great for pad sounds. Switches and knobs allow modulation of all the usual suspects and beyond but what is really cool is that the DE has out- and inputs for control voltages and as such is a perfect start for a modular system. Even with only the DE you can do stuff like route the CV for note velocity (that the DE generates from the midi in information) to its VCF cutoff so you get a note that gets brighter when you hit the keys harder. Or how about routing the LFO cv to the DE's ENV gate input so you get a repeating tone without any arpeggiator or step sequencers in sight?
Understanding everything that the DE can do is very complex and to be honest not something that I claim to do at the moment. However, the basics are easy to grasp and it really invites playing and tweaking because everything is there, everything has its own knob or switch. Tweaking and sound manipulation soon becomes second nature and improvising is a blast. The mp3's I'm including were done just like that, connecting the DE to my XA and improvising. There is no sequencing and layering of tracks involved, aside from some drum loops on my Fantom Xa in demo 1 and a pad sound in demo 2 which is played in conjunction with the DE, showing of the high-note priority the DE has.
Hope you all enjoy the demos and let me know if there are any questions!