Atomosynth revives its Mochika line with the X7, a semi-modular analog synth built for patching and performance. It packs two oscillators, a vactrol filter, a delay and a 32-step sequencer, in a desktop unit or a 48 HP Eurorack voice.
A cult line back from the workshop
Atomosynth is a small Peruvian builder whose Mochika series has followed analog-synth enthusiasts for more than fifteen years. The X7 keeps that spirit — a raw instrument you shape at the patchbay — while adding the conveniences you now expect from a self-contained machine. It sits firmly in characterful subtractive territory, halfway between a workshop object and a stage instrument.
Two oscillators, a vactrol filter
The first oscillator (VCO) offers square and sawtooth waves with pulse-width modulation. The second, a more stable DCO, adds triangle and sine and widens the harmonic palette considerably. But the character really comes from the vactrol filter: both low-pass and high-pass, with continuously variable cutoff and resonance, it delivers that soft, organic grain opto-based filters are known for.
Envelope, LFO and onboard delay
Modulation rests on an ADSR envelope and an LFO whose shape sweeps continuously between pulse and triangle, with a symmetry control that sets pulse width or ramp slope. The X7 also carries a CV-modulatable delay, good for tidy echoes as much as for outright experimental drift when you patch it back into itself.
A 32-step sequencer that steals the show
This is the big change from earlier Mochikas. The sequencer offers 32 steps and nine playback modes — forward, reverse, ping-pong, random, drunk, step-trigger, worm, scrub and MIDI control. Each step is tunable in detail: pitch on/off, gate, gate time and retrigger, repeat or skip. The machine stores up to 100 patterns in non-volatile memory and syncs to external clock, MIDI clock or USB MIDI.
18-point patchbay, OLED and encoders
The patchbay has 18 points — nine inputs and nine outputs — exposing the oscillators, filter, delay and modulation. A high-contrast OLED display and eight push encoders make up the interface: it stays hands-on, without sinking into endless menus.
Two formats, a waitlist price
| Spec | Detail |
|---|---|
| Oscillators | VCO (square, saw, PWM) + DCO (square, saw, triangle, sine) |
| Filter | Vactrol low-pass and high-pass, continuous cutoff and resonance |
| Modulation | ADSR envelope, LFO with variable shape and symmetry |
| Effect | CV-modulatable delay |
| Sequencer | 32 steps, 9 modes, 100 patterns, clock/MIDI/USB sync |
| Interface | OLED display, 8 push encoders, 18-point patchbay |
| Formats | Desktop (3D-printed enclosure, 19 V supply) or 48 HP Eurorack module |
The desktop version is listed at an intro price of $399 ($449 later), the Eurorack module at $349 ($389 later). Atomosynth runs a waitlist, shipping from Peru via DHL Express; no firm availability date has been announced yet. You can track progress on Atomosynth’s site.
My take
The Mochika X7 ticks the box the range was missing: a lovable, patchable analog semi-modular that is finally self-contained thanks to its sequencer. The vactrol filter and modulatable delay promise the slightly dirty grain a plug-in never quite nails. The catch is the cost of craft: a waitlist, a 3D-printed enclosure and shipping from Lima that will test your patience. For anyone who loves characterful machines and can wait, the fun-per-dollar looks very tempting.
