There’s a new wave of products in the world of analog synthesizers as of late.
An ever-rising plethora of YouTube videos now showcases what has become an emerging trend: Small, easy-to-use music machines that pair intuitive and simple sequencers with your synth or drum engine of choice.
Such interplay can be unexpectedly deep and complex, and the Circuit Mono Station certainly has some quirky little secrets hidden up its sleeve, as I found out while putting the synthesizer through its paces over several months of use in the studio.
Features and Use
The Circuit Mono Station is sort of a Frankenstein of two of Novation’s most successful products: The sequencer-driven Circuit (a groovebox with two digital synths and user-uploadable drum samples), and the all-analog Bass Station II synthesizer—now a regular in many studios that require a flexible and dependable analog voice for lead and bass duties.
The Circuit Mono Station is effectively a mash-up of these two general concepts, and its feature set is a long and impressive one. Under its hood, an analog, dual-oscillator paraphonic synthesizer is combined with a sixteen-step sequencer, all built into a very sturdy and travel-friendly black plastic casing.
The main 1/4” line output is complemented by 3.5mm gate and CV outputs, MIDI In/Out/Thru functions (albeit with dedicated adapters), Clock In/Out, and a 1/4” jack for Audio Input—all of which make this an extremely well-equipped synth. There’s also one more output: Aux CV, which I found to come very much in handy. (More on that later).
The two analog oscillators in the Mono Station each have a four octave range and a choice of four waveforms—sine, triangle, sawtooth, and pulse width. These go through a mixer section with level controls for each oscillator, as well as separate level knobs for noise, audio in, ring mod, and sub.
The multi-mode filter includes two slopes—the familiar 12dB and 24dB—and can get very juicy very quickly. The filter is also supplemented by two stages of dirt: A pre-filter overdrive, and a post-filter distortion that comes in three flavors. Both pushed the synth engine into “modern tones” territory with ease.
Because the Mono Station is paraphonic, each oscillator can have an independent pitch and can be sequenced separately, but both still use the same global filter and envelope settings.
There are two paraphonic modes available: One in which oscillator two is only heard when oscillator one is triggering the envelope, and one in which each oscillator has full ability to trigger the envelope. The first mode is handy more for experimental sounds, where it can add a layer of depth to the Mono Station’s standard subtractive synthesis architecture.
There is also the ability to record automation data for every single parameter on board (all 53 of them) in addition to note sequence data. The only downside of this feature is that at times, it can be difficult to keep track of all of it, especially on longer sequences.
Because of all of this functionality, there’s a lot to take in on the front panel. This can be both a blessing and a curse. There are many chunky knobs and a very smooth ASDR fader section, and the cutoff knob for the filter is thankfully large and easy to grab. But there are also quite a few “shift” functions—as well as some hidden functions activated by pressing two buttons simultaneously.
Modulation comes courtesy of one LFO and what is known as the “Modulation Matrix”. Four sources (the LFO, envelope, velocity, and a modulation-specific sequence track) can modulate eight destinations, with either positive or negative depth.
Assigning modulation is as easy as selecting the source and destination and turning the knob, which glows in color according to depth. The Aux CV output is one of those destinations, and it allows you to use any of the sources to control external Eurorack modules or older analog gear that is CV-equipped. If your studio has a lot of modular gear, this functionality allows the Mono Station to integrate in a really seamless way.
The row of four by eight buttons that takes up the bottom half of the Mono Station functions as a keyboard, but can also serve various sequencer functions. It’s worth mentioning that the buttons on my unit were fairly stiff when compared to other pads. If you prefer to have a little “give” in your pads, it’s worth testing out the Mono Station in person.
Using the sequencer in the Mono Station is going to feel like second nature if you are a user of the original Circuit. If not, you will definitely need to crack open the manual to get your bearings, which points out a key missing feature of the Mono Station: A screen. The lack of a screen means any type of feedback or communication from the unit is indicated by a combination of lit, colored pads; sometimes what these are pointing to is not immediately clear.
Digging into the Mono Station’s sequencer is where the fun really starts to begin. Each oscillator has its own sequence, and there’s a dedicated sequencer track for modulation. Programming steps is as easy as holding down a pad in the sequence and selecting a note to correspond to that step. Each step can have individual velocity, glide, and gate values.
Editing these steps is fairly intuitive, which is another nice feature of the Mono Station, making setting up 303-like acid lines a breeze. Pads are velocity-sensitive, though fixed velocity can also be set. Furthermore, velocity can be set to VCA volume but can also be re-routed to any of the other modulation destinations. Setting velocity to control distortion level, for example, gives the Mono Station a real organic growl and allows for a lot of expressivity.
By far, the most interesting thing about this three-part sequencer is that each part can have individual pattern settings. Pattern length, start point, and direction (forwards, backwards, ping pong, random) can all be set independently for each oscillator and the modulation sequence; this makes it very easy to get polyrhythms going.
Pattern sync rate also makes it easy to go into 1/2 or 1/4 tempo per part, which is fun for rhythmic variations. If you’re a fan of the Korg SQ-1 or older sequencers like the Doepfer Dark Time, this feature really shines. Allowing each sequence to act independently means that parts which start off in normal 16th note bass territory get wild and syncopated very easily.
There are a total of 256 steps possible, as you can chain 16 patterns together or combine patterns in what is called a Session, which can hold 32 patterns. A slight downside here is that it’s easy to quickly forget what patterns are held in each destination slot; another reason a screen would have been handy.
One final feature worth mentioning—which adds a lot of value for live performance use—is something Novation calls “Mutate”. Mutate is a quick way to add a bit of randomization to your patterns, as it destructively changes the note values to different steps while retaining basic pattern settings (like sync rate and direction). Think of it like hitting the “random” button in Ableton.