The Delta CEP A is described as a Paraphonic Modular, and indeed that’s exactly it. With a Swarm Oscillator at it’s heart, it's got some clever DSP work going on. Indeed most of this synth is DSP based apart from the VCA and the Analog filter (there are also two digital filters). it adds to the growing number of Eurorack modules that now makes up the range - indeed you can hook up a second Swarm Oscillator via a special connector for some extra swarm action.
With a semi modular design (32 points) and 40 patch storage locations, it can deliver some complex monophonic sounds - with up to 8 discrete chord pitches (with detune), or massive stacked detuned sounds, plus a four voice paraphonic mode with two oscillators per voice. The swarm aspect means that there is just a single oscillator control with a separate density and detune parameter.
With Sine, TRI, SAW and Square waves on a morphing control, you can modulate both the Waveform and the Wave shape (for PWM for example) it's sounds pretty fine to my ears and is capable of both sweet chordal work in paraphonic mode and massive stacked detuned waves when swarmed up.
Oscillator level has a top 25% which takes it into a pleasing sounding DSP distortion and can really warm up.
After this, the filter is a hybrid, multi-mode affair, with three types:
Each of the modes can we switched separately so it's possible to have LP+HP, or BP and HP etc.
With a massive stacked swarm oscillator going into it, it's got a really pleasing sound.
The 2-pole DSP filter works in stereo, so LFO modulation will be L+R with the inverse of the LFO wave in the opposite speaker - quite a nice effect, you can disable this by working in mono or using one of the other filters.
A single LFO goes up into audio rates and can be tuned into a fixed pitch, though sadly not trackable via scaled CV input (shame). Sine, Tri, Ramp, Square and Random - all clock-able via internal tempo or external MIDI.
ADSR envelope also has a gate mode which means it's possible to have an additional A/R slope to the basic gate shape in addition - no looping on this though.
Finally, a stereo digital effect with Tape, Delay, Phaser, Chorus, Flanger modes (with modulation on the delay time also possible). You can get some really tight delay and feedback for some extreme sounds and a bit of Karlpus style tones too.
There’s also a pitch quantizer, useful for internal use - LFO can be quantized to any of the on board scales to drive the Oscillator, or just used as a quantizer with external gear.
Multiple 1/8th jack points give you quite a wide range of patchable options, though I would like to have seen density and de-tune included as mod depth destinations. Plus there’s not quite as much normalized routing as I would have liked, LFO -> Osc Mod and Cutoff would have made sense and meant more patches could be recalled without additional cabling.
Interpolator -this is a unique feature which allows the storing of up to 8 snapshots (like sub patches) per memory - and that’s all front panel controls (apart from master volume). Each snapshot can then be morphed between, using either the large dedicated knob, internal clock, aftertouch or mod wheel. On paper it's incredibly powerful and some of the on board patches demonstrate this with some complex, sequenced percussion and synth lines.
However in use, it's quite fiddly to use, you need to be in morph mode, which disables the front panel and makes tweaking and update the snapshots a bit cumbersome for me.
Currently, the knobs and switches do not transmit or respond to MIDI - which would be great - we hear this is coming in a firmware update and would be a quick way to automate some of the non, routable parameters. But for now the Interpolator will get you there.
Audio Stereo output, Stereo input (for FX), MIDI in/out/through, 12-19V 2A input (a tasty power supply comes with the desktop version)
I like the sound of this instrument, it's got depth and girth and the DSP filter sounds really good to me. Sure it’s a bit on the pricey side, all those ins and outs need DACs and Radikal have made the choice to pay skilled workers a fair wage for their labours. But it's got a really wide palette of sounds and is a good starting point for hooking up external modular gear - yes another gateway machine.
Available now in Desktop version: £1170 and Eurorack £780
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