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Thursday, November 21, 2013

Moog Minitaur

Analogue Synthesizer

Reviews : Keyboard

Analogue Solutions make a bid for your cash with a retro-styled synth offering big, fat Moog-style sounds and a built-in sequencer. Could this be their best synth yet?

Paul Nagle

Analogue Solutions Leipzig S

Analogue Solutions have been quietly beavering away for many years on a diverse brood of analogue synths, sequencers and the Concussor range of modules, many bearing Russian names such as Vostok or Tereshkova. In this outing, Germany provides the nominal inspiration for the Leipzig S, a rackmounted, monophonic synthesizer incorporating MIDI and a step sequencer (hence the S). For those who'd prefer a keyboard-based model, there's the Leipzig K, which forgoes the sequencer but adds CV and Gate operation, plus lots and lots of wood.


Back To Black

Picking up the Leipzig S (which I'll refer to as simply Leipzig from now on), I found it to be heavy metal — but without a leather jacket or shades. Its knobs are impressively large and well-spaced, the exception being a row reserved for the sequencer, which are of a different style and more closely packed together. Close scrutiny reveals four tiny switches nestling against some of the knobs, and a little breathing room wouldn't have gone amiss there, but they worked fine without causing undue knob fluctuations.

The rack ears aren't detachable, but if you do prefer desktop operation, there are four sturdy feet that place the Leipzig at a workable angle. Following the recent trend of Dave Smith Instruments and Moog, all the panel text is printed onto an overlay. This one alerts you of its presence by ending somewhat short of the instrument's full width. And while the front panel is secured by three screws at either side, none are apparent along its length. This makes the middle slightly flappy, but when the synth is in a rack, that shouldn't be an issue.

More praiseworthy are the recessed sockets that ensure precious rack space is not taken up by MIDI, audio and power connections. Supporting the MIDI In socket is the oft-forgotten Thru and a socket for the external power supply. This leaves just three quarter-inch jack sockets: the main audio output and two external inputs — about which more later.


It's Alive!


The front panel features clearly demarcated sections and widely-spaced knobs. The very bottom section is given over entirely to the sequencer.  

The front panel features clearly demarcated sections and widely-spaced knobs. The very bottom section is given over entirely to the sequencer.

Attach the power adaptor and the Leipzig springs into life. Several red LEDs shine through the overlay, informing you about LFO speed, envelope triggering and so on, while a row in amber marks the progression of the analogue sequencer. The LEDs are at their most visible when viewed square on, being quite deeply set.

For instant gratification, you can start sequencing right away without a keyboard connected. With a spin of the multi-position switch in the bottom left-hand corner, select LFO sync. Then, assuming both envelopes are enabled for sequencer control (by the switch in the top right-hand corner), a hot and potentially manic eight-step sequence will gush forth. Quickly grabbing the main volume control, I wondered if this could be the first synth that registers on the Richter Scale; certainly the seismic activity in my studio was as applicable to demolition as it was to the music industry!

The Leipzig is a two-oscillator analogue design with an easy-to-follow layout and circuitry that is unashamedly Moog-inspired. Each VCO has independent glide and a choice of sawtooth or square waves. Unusually, these waves are balanced by a single knob, of a type seen on classics such as Oberheim's SEM (Synthesizer Expander Module). The main plus point of this is that a large number of options can fit comfortably into a modest panel footprint. So you turn a knob clockwise to introduce the square wave, anti-clockwise to fade up the sawtooth. In the centre position (marked by a gentle notch), there is no output — or almost none. On the review model, there was a small amount of low level bleed-through from VCO2.

The master tune control offers approximately an octave of transposition up or down and VCO2 can be separated from the first by only about an octave. (The Leipzig's vintage behaviour stirred further memories when I realised that the second oscillator wasn't tracking the keyboard too accurately in its higher registers.) There is a way to accomplish greater shifts than an octave, but as it requires the use of the sequencer, I'll come to it later.

Contributing to the Leipzig's considerable audio presence are two square-wave sub-oscillators pitched an octave below the main VCOs. They, too, are introduced by a dual-purpose knob, meaning that only one may be heard at once, but this isn't a limitation. Even one Leipzig sub-oscillator is dangerously close to overkill; two would probably summon angry squadrons of EU Health and Safety inspectors from their lairs.
Continuing with the dual-pot theme, both oscillators adopt them for pulse-width modulation. A turn to the left, and VCO pulse-width gets the LFO treatment; to the right, and it is swept by envelope 2. The oscillators are similar in functionality but not identical; only VCO1 has a variable pulse width, while VCO2 has oscillator sync and a switch that detaches it from MIDI control — handy when the oscillator is moonlighting as a modulation source. The sync implementation is a blast! It includes a choice of three different sources for VCO2 to latch onto. For a familiar sync experience, you'd select the first of these, VCO1, but when exploring Leipzig's modulation possibilities, a useful alternative is to sync to the LFO instead. Finally, there's the rare option of sync'ing to any signal connected to the EXT1 jack. A natural source to try would be an oscillator from a modular synth, but anything is fair game! 

The Leipzig S's recessed back panel includes quarter-inch sockets for two external inputs and audio output, an input for the external power supply and MIDI In and Out ports.  

The Leipzig S's recessed back panel includes quarter-inch sockets for two external inputs and audio output, an input for the external power supply and MIDI In and Out ports. Modulation centres on a three-way bus dedicated to frequency; specifically, the pitch of both VCOs and the filter's cutoff. In each case, there are a choice of sources and a single amount knob. The LFO's two waveforms (triangle and square) are available to every destination, with other sources chosen to provide the best range of effects. Thus VCO1's pitch is modulated by envelope 1 or by VCO2's square wave output, the resulting FM packing oodles of grizzly harmonics. VCO2's sources are slightly different — the second envelope or a MIDI controller of your choice. By combining oscillator sync with envelope modulation, you can serve up familiar Rogue-style sweeps with just a tiny amount of modulation. At higher depth settings, the sync'ed oscillator is pushed into a range I can only describe as 'waywardly eccentric'.

The filter's additional modulators are either a chosen MIDI controller or the square-wave output of VCO1. Admittedly, the Leipzig's filter FM doesn't sizzle like, for example, a Prophet, but it still snarls in your ear like an angry terrier when roused.

Speaking of the filter, I found it a strange beast. On the one hand, it's a big, fat Moog filter for big, fat basses. On the other, someone castrated the resonance knob! For the majority of its travel, the knob does nothing, zilch. Then, just as you think it's dead, a whistle breaks out. There's a very small amount of travel prior to self-oscillation that offers a hint of what a fully-functional resonance would have been like. Believing this to be a fault on the review model, I contacted Analogue Solutions, only to be told that this was indeed how all Leipzigs are shipped (!). This is a shame, because there's a hefty bottom here that could benefit from traditional Moogy resonance. At least AS did promise to revisit the design at some point in the future for customers not technical enough to address it themselves. The filter also offers keyboard tracking and another dual pot selecting which envelope should be the filter shaper — top idea! The envelopes are both snappy ADSR types, with a switch to determine whether they are triggered by MIDI notes or by the sequencer.

We've now reached the synth's output stage, where the only thing left to report is that the VCA, too, has multiple options. Thanks to another switch, either ADSR can drive the output, and there's a simple gated envelope (on/off) and a 'Thru' option, where all audio is allowed to pass unhindered. When all you want is to squish an external signal with the filter, you'll appreciate Thru!

Which reminds me: I should mention one last dual pot, in the mixer section. This one either sets the level of the incoming audio signal (connected to EXT2) or of the white-noise source, but flip a switch and noise is replaced in the mix by the output of the sequencer. If this sounds like an odd thing to do (sequencers are usually thought of as CV sources), read on...



The eight-step sequencer is fun, if a mite idiosyncratic. As it's thoroughly analogue and unquantised, you need to tune each step manually, by stepping through them with a button, adjusting each in turn. Years of conditioning has us associating conventional tuning with synthesis, but if you yearn to break free, an analogue sequencer is an ideal escape route. Old-style sequencing is a primal but wholesome pleasure and even if eight isn't a huge number of steps, it's enough when you're tuning them manually. To help you extract more from your sequences, they can be transposed by a MIDI keyboard.

Three destination pots at the Leipzig's lower right-hand side mirror the destinations of the modulation bus; they set the amount by which the sequencer drives the oscillator pitch and filter cutoff. Using the sequencer alongside existing modulation is a means of breeding sequences no mouse would click into life, and by setting only one of the oscillators to be modulated by the sequencer, you can push them further apart than one octave.

Frustratingly, the review model's eighth sequencer knob was faulty, the result of one too many trips through the post, perhaps. This hampered my sequencing, because the busted knob had a far smaller tuning range than the others. The Reset switch came to the rescue, with its ability to kick the sequence back to the start after incoming notes with a velocity exceeding 80. When harvesting loops later, for my own nefarious purposes, this was an essential tool.

In common with Analogue Solutions' Europa sequencer, every practical sync option is provided, the most obvious being the one we tried earlier, where the LFO is the clock source. For the more experimentally minded, the sequencer can be clocked at audio speeds by selecting VCO2 as the source. The waveform is then 'shaped' by adjusting each sequencer step, a simple act that brought back fond memories of my ARP sequencers.

Yet more clock sources remain to be explored; a good one is 'MIDI key', where the sequencer advances a step for every note received. Restrict the sequencer's control to the filter only and you have an easy hands-on way to add funky cutoff changes to a solo or bass part. For a variation on this, switch to 'Accent', where sequences are only stepped by high velocity notes. Finally, you can sync to an external clock connected to the EXT1 socket or to movements of an auxiliary controller.



Despite a glitch or two in the quality-control department, I really enjoyed playing and sequencing the Leipzig. Sonically, it reminded me of a Moog Rogue — but a Rogue force-fed on burgers and lard before being squeezed into a rack. I was amazed to find resonance implemented as it was, but if resonant subtleties aren't a priority, the Leipzig has a lot to offer, such as versatile switching, snappy envelopes, devilish oscillator sync and enough bass to build pyramids on.

There's more. A step sequencer is always worth having, and even if this one looks slightly like an afterthought, it opens up avenues that sequencer-challenged synths can only dream of. Ultimately, the Leipzig is a powerful analogue synth module that's reasonably priced compared to ageing Moog Rogues and Prodigies. It's quite possibly Analogue Solutions' best synth to date!  .\

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