Sonocurrent’s M C3A Crossfade Array is, as the name suggests, an 18hp, three-stage voltage controlled crossfade module. While a bit of a mouthful to say, it’s a deceptively simple concept in a module that opens up a rabbit hole of possibilities thanks to some clever features.
The M C3A consists of two parallel and identical crossfade sections [A and B] that feed into a central third stage [C]. A and B each have two signal inputs [the module is DC coupled and is happy with audio and CV] and a CV input for voltage control over the crossfade position. There are outputs for both the crossfaded signal as well direct outs for the crossfade CV [in the absence of any CV input these will output a static voltage controlled by that channel’s crossfade knob position over a 5 volt range from -2.5 to +2.5 volts with 0 at the 12 o’clock position.] Channels A and B both have level attenuators for their two inputs, a CV input attenuator, and a large knob for manual control over the crossfade balance. The central channel has the manual crossfade control as well as a CV input attenuator but is fed internally by, and crossfades between, the output of channels A and B. Additionally, all three channels have a pair of LED lights that indicate CV input signal activity as well as polarity.
All three channels of the M C3A can be used as straightforward VCAs by only utilizing one of a channel’s two inputs, and with an envelope into the CV input, crossfading from signal to silence. Equally useful for both audio and modulation or control signals, the M C3A makes quick work creating complex and evolving modulation from relatively simple sources. Feed 4 different simple waveform shapes into the available channels and set your relative levels to taste. With LFOs into each channel’s crossfade control you’ve got three distinct yet related signals at each of the dedicated channel outputs. This fun applies to audio rate signals as well and you can mix and match or run A and B as separate signal paths.
The M C3A is a drone-maker's best friend and rich timbered walls of sound are only a few patch cables away. Crossfading between noise and an oscillator added a pleasing grit that could be subtly modulated in and out for more or less dirt, and I also had a blast using the M C3A as a weird drum mixer by layering different parts on different channels and manually giving more prominence to one input or another. It was a really effective way to give movement to a rhythmic part while maintaining the overall vibe. Conversely by inputting parts with different rhythms or subdivisions [or euclidean patterns] and then crossfading between them you can get some really nice—or disorienting—evolving polyrhythms. Setting up the M C3A as an effect mixer with the crossfaders acting as a wet/dry mix works great as does more straightforward signal mixing and having the CV pass-through [or offsets] for each crossfade stage lends fantastic utility to the module. Being able to effectively mult out a modulation signal [or audio as the crossfade CV input will accept both] and pass it along to other parts of a patch is a nice touch, great for keeping everything in your patch on the same page.
Sonocurrent modules are solidly built and the M C3A is no exception. It has an attractive gun-metal grey, brushed aluminum panel, solid and grippy knobs, and an ergonomic layout with plenty of room for manual wiggling. In fact, the only thing that I could pick at in terms of design is that some of the subscripted channel indication markings on the front panel are hard to read, though once you’ve grokked where everything is, it’s not really an issue. With a clever design and a smart feature set, M C3A easily earns its HP, whether you use it as a complex crossfader, a mixer, or even a VCA in a pinch.
18 HP +12v 80mA -12v 75mA