The first thing I noticed about Cambridge-based BlaknBlu’s Oscar Tria (a stereo digital oscillator), Alpha Duo (stereo VCA and ring modulator), and Foxtrot Duo (stereo multimode virtual analog filter), is that all three modules employ the same layout for the controls and patch points. This is something you see a lot with pedal manufacturers, where enclosures are the same from model to model, but almost never so in Eurorack. Whether this sameness of layout is for efficiency of manufacture, user familiarity, or perhaps to set parameter limitations on the design (limitations are NOT a bad thing), is hard to say, but all the outputs for all the modules are on the left side and middle of each module, which is out of the norm. It's not so much that it's odd as that I'm so used to, so conditioned to seeing jacks only at the top or bottom of modules (or maybe at the side edges, in some cases), and I do prefer it that way, especially since the CV inputs (and attenuators) are at the bottom of each module, and the inputs (with attenuators) are at the top of the module on each side of a two-position toggle. While these are all digital modules, they behave in an analog fashion and are devoid of any screen or menu, both to their benefit (as on Alpha Duo), and a bit to their detriment (as on Oscar Tria).
Oscar Tria packs a lot into a 10HP frame (all the modules are 10HP). With three modes available: Green mode, a traditional stereo VCO; Yellow mode, a super waveform (saw, triangle, square) + a sub-oscillator; and Orange mode, a twenty-chord mode, there's a lot to discover. Some of the naming of functions seems odd; there's a Page 1/Page 2 switch, more akin to a module with a screen, that gives the controls on Oscar alternate functions; Waveform controls the -1 sub osc level, PW controls the -2 sub osc level, and the Pitch knob detunes the second oscillator (the Right output). With two pages, it could be a bit confusing, but the controls when on Page 1 are the same for all modes; the Waveform control determines the VCO shape, the Pitch control the tuning, and the PW control the width of the pulse wave, and only Page 2 means something different depending on the mode. This is exemplified by the color of text surrounding each control as the text color matches each mode's Page 2 functions. On top of the Mode and Page 1/2 toggles, there are also Octave, and CV Mode switches, which sums or separates the two CV inputs. Depending on the mode, you can get hard sync, TZFM, swarm oscillators, and polyphony with chord selection. In Green mode, as a traditional stereo VCO with waveform morphing between saw, triangle, and square (along with square sub-oscillators, with -1 and -2 available), you can get some very fat, very deep tonalities—excellent for bass lines—and you can CV the waveshape, and the PWM. Yellow mode is for the swarm setting, and it is indeed buzzy, but not quite as dynamic as I'd hoped—it feels very centered, even with both oscillators panned hard right/left. Its Page 2 functions, the pan specifically, (along with control over the sub octaves) just didn't add enough to this mode, and I would have preferred to detune, or spread, the oscillators apart as in Green (and Orange) mode. Orange mode is a bit more in-depth in that you can use it for chord generation. As there is no menu or screen, it's not always easy to determine which of the twenty chords are selected—let alone remember them all—as that function is determined only by the continuous Waveform knob. Maybe that doesn't matter too much, depending on your usage. I like that the Pulse Width knob controls how many notes are in the selected chord (up to five), and you can CV that, which is pretty cool. You're also able to detune the two oscillators here, which can get pretty interesting and ugly (in a good way), especially when the note amount for the chord is up there and the chosen chord has some complexity to it. Oscar Tria remembers the settings from mode to mode, so you can switch modes and not sweat having to remember the setup, though this disappears once you turn it off—there are no saving/recall capabilities. A versatile VCO, there are a lot of good moments to be had here.
Foxtrot Duo, a multimode VCF that can operate in mono, where the two inputs are summed before entering the filter; or in stereo mode, where you have two separate channels going through the same filter. Foxtrot earns its stripes; it's very flexible, and with three popular analog filter styles (though Foxtrot is digital, remember?!)—a 4-pole Moog-y ladder, a 2-pole Sallen-Key, and a state-variable filter based on Oberheim's SEM, you're getting a lot of bases covered. For controls, there's a Frequency, a Resonance, and a variable BP-LP-HP knob that lets you morph between types. All of this can be modulated and dialed in, and I like that there are two CV inputs with attenuation for modulating the cutoff. Sometimes you want to do a sweep and add a little something extra in there from time to time, and having onboard capabilities to do so is a plus. Initially, I lamented that there didn't seem to be a Res CV in, but you can do that via an assignable Aux CV input, which is where you can sweep through the filter types as well. The Aux CV can also—somewhat confusingly—when in Mono, split the filters into a stereo pair (mono, stereo, stereo, mono…) and pan things around. It was really interesting when I switched it to Stereo and patched a stepped S&H in there to control the offset of the frequency between the two filters. Some great movement was happening, and this was all while leaving the tuning static on my VCO (Oscar Tria, naturally). Actually, I preferred it that way as opposed to patching in a 1V/Oct.
Though I didn't have the ability to do side-by-side testing on them all with the real things, and even though they are digitally derived, all three filters sounded pretty good. The ladder dropped off nicely with a pleasing edge, when pushed the Sallen-Key had the unmistakable howl of early Korgs, and the sound of the SEM was impressive, showing teeth with the Res on high, and backing off nicely with lower resonance. It opened and closed up nicely when in LP mode, and sounded great sweeping it in BP. Overall, a really nice filter with some unique takes and a lot of uses. The modulation for controlling the frequency offset of the two filters is worth the price of admission alone. Really cool.
Last of the bunch is Alpha Duo, a stereo VCA with ring mod capabilities. This is the simplest of the three, in terms of functions, still with some interesting twists. Being able to process two inputs for either summed mono or stereo operation, Alpha also adds three different drive/distortion flavors, true stereo panning capabilities, and has a Quadrant selector, which is where you can get your ring mod flavor. Overall, I found Alpha Duo useful, with nice features, and the drive added some nicely different flavors, which seemed to change a bit depending on what Oscar was sending through it. Chords sounded really nice and nasty, and The VCA input gain can be attenuated and the applied CV is switchable from log or linear, like most mid-featured VCAs, and with the drive settings you can color the signal pretty well. Alpha seemed a bit vanilla at first, and really, I suppose you could say it is, but it was interesting switching modes, quadrants, and it was worthwhile doing some ring modulation in stereo.
Using the three modules together as a unit, all patched up..those gritty, ring moddy chords with contracting note amounts was indeed a bit different and definitely entertaining. While I still don't like the placement of the outputs, with some right angle Tendrils cables, it was easy enough to tweak and destroy; to switch filter modes, VCO modes, and pan it all around. Even though they are fine on their own, it's obvious that Oscar, Foxtrot, and Alpha want to be together. The identical layouts, the names, the adherence to stereo…I found it hard to separate them. These are interesting modules, and worth seeking out.
Price: $329 each

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