Let's have a look at the Novation Circuit Mono Station. It looks like a nightclub, doesn't it? There's a dancefloor with glowing floor panels, and a DJ's mixing desk. But it's not a nightclub. Oh no. It's actually a surprisingly fully-featured synthesiser with a built-in pad-based sequencer.
Just look at all those colours:
Novation released the Mono Station in 2017 as part of their Circuit range of groovebox sequencers. Sound on Sound liked it, but while the other Circuits were updated or replaced circa 2020 the Mono Station was quietly discontinued. I think the problem is that it was marketed as an all-in-one analogue sequencer workstation, but it's really just a synthesiser with an admittedly smart sequencer, a kind of super-sized Korg Volca. Unless you do some clever programming it can only play a single bassline with no drums.
At heart the Mono Station is a Novation Bass Station 2 synthesiser combined with a Novation Circuit sequencer. You can in theory just use it as a Bass Station 2, ignoring the sequencer entirely, in which case it's actually cheaper on the used market.
Let's talk about the bits. The original Novation Bass Station came out in 1993. It was a two-oscillator monosynth housed in a cute little case, with a two-octave keyboard. At the time it was sold as a clone of the Roland TB-303 acid house bassline synthesiser, but it was much more versatile. It could do analogue lead lines as well. For a long time it was the only affordable analogue synthesiser on the market and it sold like hot cakes.
Novation upgraded the engine in the following years. The Super Bass Station rackmount of 1997 added a sub-oscillator, ring modulation, white noise, and a distortion effect, which meant that it could also double as an analogue percussion generator. For the next few years Novation concentrated on the Nova digital synth, but in 2013 they launched the Bass Station 2, which added a bunch of upgrades including oscillator sync and (with a firmware upgrade) duophony, essentially turning the Bass Station into a modern analogue of the ARP Odyssey or Sequential Pro-One.
The Mono Station's synthesiser engine is a Bass Station 2 minus one of the LFOs, minus one of the envelopes, minus the TB-303 filter emulation, minus oscillator cross-modulation, but what remains is still pretty versatile.
It has two mixable oscillators, sine-triangle-saw-square, with variable pulse wide on the square, although you can't set this manually. Pulse width has to be modulated. There's a slightly underwhelming sub-oscillator, plus white noise and an audio input. The audio input goes through the envelopes and the filter.
It also has ring modulation and oscillator sync. The Mono Station's manual does a poor job of explaining how to make oscillator sync sound good - it works best if you apply a bit of pitch modulation to the sync source. At that point the sync effect makes the distinctive beoooo sound.
There's a single, multi-envelope, sync-able, key-syncable LFO that can be assigned to pitch, pulse width, filter cutoff, and the distortion effect. The distortion has three types, all of which have a digital-sounding crackly crunch. There's also a relatively subtle overdrive effect. As pictured above the Mono Station uses glowing LED lights to show the depth of a modulation source.
The six-part, button-driven modulation matrix is easy enough to use, although it would be nice if there was a way to quickly zero out the modulation. Sometimes I found that my patch sounded odd, at which point I had to click through each of the six modulation destinations to make sure that they weren't interfering with the sound. The modulation depth knob doesn't have detents, so you have to be really precise to zero out the modulation.
The Mono Station has one envelope and one LFO, which is reminiscent of the original Roland SH-101. Sadly this means that you can't combine a slow-running filter sweep with fast-moving pulse width modulation, for example. But it's work-around-able.
There are two filters. The 12dB filter has a bright sound. The 24dB filter is darker-sounding, more Moogy, very powerful. I've always had a penchant for Doctor Who-style chunk-a-chunk bass sounds, and the 24dB filter is good at that.
Unusually the two oscillators are independently addressable. Ordinarily the Mono Station acts as a two-oscillator mono synth, but if there are any notes in the second sequencer channel they're assigned to the second oscillator. This also works with incoming MIDI information, with the two oscillators using two selectable MIDI channels. By default the Mono Station's single envelope is only triggered by the first sequencer channel, so oscillator two only appears in the shadow cast by oscillator one, but there is an option to trigger the envelope from both channels.
As a MIDI synth module the Circuit Mono has one problem that annoyed me. It transposes incoming MIDI notes to the selected scale. It puzzled me for ages until I realised I needed to set the scale to chromatic if I wanted to address every note. A subsidiary issue is that the scales aren't labelled. It would have been nice if Novation had simply cut the range down to eight scales - there are sixteen scales, which feels excessive - and labelled them underneath the lower row of pads.
Which brings me to the sequencer. There are three channels. Channel one controls oscillators one and two. The second channel controls oscillator two. And there's a third channel that contains modulation data, which is useful if you want to layer a pattern of accents on top of several other sequences. A later firmware update turn this into a fully-fledged third sequencer channel that can drive external gear from the Aux CV output.
The sequencer has some clever ideas, but also some limitations. Each channel can have an independent pattern chain. You can set channel one to loop after four patterns while channel two loops through three patterns, and the patterns themselves can be shortened from sixteen steps. Chaining them together is a simple matter of holding down the first step and then pressing the other steps in sequence, but as with the Korg Volcas you can only step through the patterns in order. You can't program a song that goes 1-1-1-2-1-2-3-4, for example.
The process of programming the actual notes reminds me of the Arturia BeatStep Pro, but it's clunkier. With the BeatStep, you can cue up a sequence and then selectively mute notes while the sequence plays, or add notes transparently, which is great for live sequencing. On paper you can also do that with the Circuit Mono, but in practice pressing the keyboard immediately triggers a note, which interrupts the sequence. There doesn't seem to be a way to cue up notes silently, or at least if there is I couldn't find it in the manual.
A second issue is that the current view is tied to the playing pattern. If you want to edit pattern 1, and you're playing a chain of patterns that goes 1-2-3-4, you have to wait for the Circuit Mono to loop back to pattern 1 before you can edit it, and you have to implement your edit before it moves to pattern 2. In general I find the BeatStep superior as a live sequencer.
The sequencer has one major limitation. The two melody channels are hardwired to oscillators 1+2 and 2 respectively, as if Novation really wanted to interest you in paraphony. In practice this means that anything you put in sequencer channel 2 triggers the second oscillator. It would have been nice if channel 2 could have been used purely to drive external gear. The aforementioned firmware update essentially does this with the modulation channel, which is nice, and it's less of a limitation if you just use the Mono Station as a clock source, but it's a problem if you intend to use the device as the heart of an analogue studio.
Now, this is more of a feature request than a limitation, but it would have been great if the Mono Station simply had four individually assignable sequencer channels that could be set to drive any combination of oscillators or external gear. I have the impression the designers started with the Novation Circuit's two-polyphonic-synthesisers-plus-drums arrangement and simply transposed it to the Mono Station, but it doesn't make as much sense on a monophonic synth that hasn't got a separate percussion engine.
Are there any other limitations? The Bass Station 2 has an arpeggiator. The Mono Station doesn't. You can in theory program a pattern as an arpeggio, but there's no way to transpose it, either with the keyboard or with incoming note data.
This is why I think of the Circuit Mono as a Bass Station 2 with a built-in sequencer rather than as a fully-fledged groovebox. The original Novation Circuit had rudimentary reverb and delay effects, and a drum channel. The Circuit Mono Station doesn't have that, so if you plan to use it as a portable ideas notepad you'll probably get sick of sixteen-step basslines, at which point it becomes very limited. A simple Tangerine Dream-style delay would have been nice.
If you plan to take it on a journey with you the Mono Station is roughly the same size as two Korg Volcas. It'll synchronise with them using simple mono Eurorack patch cables, but you would of course need a small mixer as well. The Mono Station has an audio input, but it goes through the filter and envelope, which can't be bypassed. You can of course pair it with a MacBook Air, but you'd need some kind of audio interface, because the Mono Station's USB connection only carries MIDI. Of note the Mono Station relies on a 12v mains adapter for power.
How would I have implemented the Mono Station? I would have taken one of two directions. If money was tight I would have dropped the paraphonic, duophonic aspect, dropped the ring modulator, added a delay effect, and also added four individual, assignable sequencer channels, with channel one optionally driving the internal synthesiser and the others driving either the CV output or a selectable MIDI channel. If there was room for a simple drum synth on the unit, or even just a bunch of drum samples, I would have thrown that in as a bonus.
Or, if the economics were viable, I would have given the Mono Station four individual, assignable sequencer channels, and four separate single-oscillator synthesiser engines, one per channel, that could be combined in different ways. This would have turned the Mono Station into a Vermona Perfourmer with a built-in four-channel sequencer. The end result would probably have been very expensive, but I can't think of anything else like it on the market. The end result would have been Depeche Mode's Speak and Spell in a box.
So, that's the Circuit Mono Station. On the positive side, it's a cheap way to get hold of the guts of a Novation Bass Station 2 in a compact case, and the sequencer is handy. On the negative side the sequencer has some major limitations, but on the positive side again it's much easier to use than the sequencers built into Korg's Volca modules. If you think of it as a kind of super-Volca it makes a lot more sense than it does as the sequencing heart of an analogue studio.
