Joranalogue Audio Design

Notes: The window comparator is a very useful circuit building block that is common in general electronics, but rarely found in modular synths. While a regular comparator activates when the input signal voltage is higher than a threshold level, a window comparator checks if the voltage is between two levels (these form the 'window').

Compare 2 combines two such comparators and a logic section in 8 HP. The result is an advanced tool for extracting gates and pulses from analogue signals in Eurorack synths.

The detection windows are defined by the shift and size parameters, which can be varied using the knobs and CV inputs. Complementary gate outputs are available, with big three-colour LEDs showing each comparator's status.

All inputs are normalised from the left section to the right, but the two comparators can also be used completely independently. On the bottom, the outputs from both comparators are combined in various ways by the logic section, which also features LEDs.

You'll find a use for this truly multi-functional module in practically any patch, processing either CV or audio: complex rhythm generator, dual pulse width modulator, frequency multiplier/divider with PWM, digital ‘ring modulator’ with PWM, dynamic depth VCO synchronizer, voltage controlled swing, logic function array with adjustable thresholds... and many more applications waiting to be discovered!

Notes: For decades, the voltage controlled slew limiter has been a staple of modular synthesisers. With its extreme versatility, it can be used to slew control voltages (CVs), create envelopes, as a low-frequency or audio oscillator and much more.

Today, Contour 1 brings a fresh approach to this classic circuit. It delivers much improved performance and control by incorporating modern design techniques.

At its most basic, a slew limiter slows down the rate of voltage change in a signal. On Contour 1, the rising and falling rates can be individually set using sliders and CV modulation.

The gate and trigger inputs allow the module to be used as a function generator: create snappy attack-release (AR) and attack-decay (AD) envelopes, with slope times ranging from 500 us to 30 seconds. The dedicated gate input makes it easy to generate +10 V envelopes from any signal source. Using the large tactile push button, AD envelopes can be manually triggered. A trigger will also reset the output voltage.

When set to loop mode, Contour 1 will continually re-trigger itself. In this mode, it fulfils the role of a variable-shape low-frequency oscillator (LFO) or temperature-stable voltage controlled oscillator (VCO) in the audio range.

Both the rising and falling slopes can be individually bent, from concave through linear to convex. While doing so, the deviation in slope time, and thus oscillation frequency, is kept to a minimum. Since the bend parameters are separately voltage controllable, boundless modulation possibilities present themselves.

Explore anything from shape-shifting envelopes to rich VCO timbres: Contour 1 will make you re-think what a slew limiter can do.

Dimensions
8 HP
30 mm deep

Current Draw
90 mA +12V
85 mA -12V

Notes: A comprehensive solution for stereo signals in Eurorack, the Enhance 2 offers stereo and mid/side processing with tons of CV control. Balance, widen and sculpt frequency bands.

Supplier's Notes:
Moving from mono to stereo sound: a logical progression for any synthesist looking to expand their sonic palette. Making use of two audio channels, rather than just one, quite literally adds another dimension to the capabilities of a synthesiser.

Unfortunately, controlling stereo signals can be a challenge within a modular system. This realisation led to the development of Enhance 2: a convenient yet high-fidelity tool for stereo enhancement. It can be used to adjust balance, width and spectral content, while also opening up a world of mid/side processing; all under voltage control and in just 8 HP.

The primary stereo parameters are balance (moving the sound left or right) and width (making it narrower or wider). The balance circuit uses a true constant-power gain law, while the width stage allows for seamless transitions from pure mono to extra-wide stereo.

In addition, tone control is provided by a pair of unique, wide-ranging mid/side voltage controlled tilt filters with selectable corner frequency. These make 'cleaning up' a muddy-sounding mix straightforward, but also provide unique binaural effects when modulated.

Mid/side processing encodes the stereo signals into one containing only the mono material (mid), and another containing the differences between both channels (side). Apart from the internal tilt filters, mid/side outputs also enable external signal processing such as compression or reverberation. An integrated mid/side decoder returns the results back to standard stereo. And at all times, a LED bar phase meter ensures that phase correlation can be easily maintained.

Stereo field modulation, mid/side equalisation and beyond; Enhance 2 brings true analogue stereo control to the Eurorack world.

8 HP
+12: 70 mA, -12: 70 mA

Notes: Designed with versatility in mind, the Fold 6 is a six-stage wavefolder with simultaneous series and parallel outputs, dual signal inputs and voltage-controlled folding and overdrive shaping.

Supplier's Notes:
Often considered to be the opposite of filters within a modular system, wavefolders are designed to fold a signal over itself multiple times. This generates additional harmonics, resulting in rich timbres.

While there is a bewildering array of filter types within the synthesiser world, most wavefolders fall within only a few categories. Diode wavefolders in particular come in just two variants: series and parallel circuit topologies. Choosing a specific folder also means being limited to specific sounds and capabilities.

For the first time, Fold 6 puts forward a 6-stage hybrid series/parallel topology, yielding a greater sonic palette than ever in just 4 HP. Having both main (series) and alternate (parallel) outputs means a single module now gives access to just about all wavefolding tones imaginable.

To take things even further, an integrated symmetrical soft clipper limits the output signals to approximately 10 Vpp, keeping the amplitude within typical Eurorack levels and making it easier to create overdriven sounds at high fold ratios. This clipping stage can be driven continuously using the shape parameter, smoothly transforming the folded waveforms into pulse waves for even more harmonic content.

Two signal inputs are included, to mix audio signals or add in a DC voltage for asymmetric folding. The symmetry can also be manually controlled using the dedicated knob. Of course, both fold and shape parameters feature voltage control, to enable continuous timbral modulation.

Moving beyond simple signal processing, Fold 6 also lends itself perfectly for feedback patching, CV folding or frequency multiplication; its modest size belies the sonic capabilities within.

Notes: While modular synthesisers are most often used as stand-alone instruments, they also present exciting opportunities for processing external signals. Anything from an electric guitar to an effects send on a studio mixing desk can benefit from the unique sonic capabilities of even a modest Eurorack system.

However, patching in an external source usually requires an adapter cable and plenty of clean gain to bring the signal to Eurorack level. If the signal source is balanced, a balanced input is required as well to provide the best possible interference rejection.

Receive 2 (or RX2 for short) provides a convenient all-in-one solution. It offers two universal external inputs, which accept both balanced or single-ended signals via XLR or 6.35 mm jack connectors.

The circuit incorporates low-impedance design practices, radio-frequency (RF) filtering and premium balanced receivers to provide transformer-like interconnect performance in a compact and affordable module. And thanks to the electrostatic discharge (ESD) protection, it’s rugged enough to survive the rigours of performing on the road.

The very clean integrated pre-amps feature variable gain, ranging from unity to +40 dB on each channel. As a result, Receive 2 can handle just about any signal source you may encounter, including electric instruments, piezoelectric pickups and many dynamic microphones.

Adjusting the gains is a breeze thanks to the dual peak-responding LED meters. A mix output is included as well, so external signals can be easily mixed directly in the module.

Notes: Flexible Eurorack signal paths under gate or trigger control: that is the basic principle behind Route 4. Consisting of a pair of complementary routing sections, it grants access to a new level of signal routing options.

The module's top section is a 4-to-1 router. Any of the four signal inputs may be selected to be mixed into the section's output, as determined by the control inputs.

Control can either be gate or latch driveniin the latter case, the signal inputs are toggled on and off by received trigger pulses. Meanwhile, the solo/multi switch determines whether the inputs are exclusive, or if multiple may be active at the same time.

With each input socket biased by a +1 V precision voltage source when left unused, gate or trigger controlled transposition of pitch sequences becomes a breeze.

On the bottom, the 1-to-4 router provides the same feature set, with a single input being routed to up to four outputs and normalisation between the sections adding some patching convenience.

All signal paths are designed for use with any Eurorack signals, whether they be control voltages, audio or gate streams. Visual feedback is provided by 10 responsive LEDs, continually displaying the status of the routers.

With Route 4, an 8 HP super-flexible analogue mixing and routing powerhouse has arrived to fuel your patching imagination. The ability to redirect signals within a modular system on the fly, with an unparalleled level of control, is sure to excite even the most seasoned patcher.

8 HP | +12: 35 mA, -12: 20 mA