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: Belgian analogue innovators Joranalogue serve up an ultra-versatile filter module. Multimode flexibility meets self-oscillation for added sonic versatility. A hell of a lot of filter for the money.

Supplier's notes:
Representing the cutting edge in modular analogue voltage controlled filter (VCF) design, Filter 8 offers more possibilities and higher fidelity in 12 HP than ever before.

Starting from the classic OTA-style 4-pole cascaded lowpass (LP) topology, Filter 8 features separate LP outputs, each with their own character. Additional filter responses are achieved by pole mixing: 1-pole highpass, a special band boost and notch response, phase shifter and 4-pole bandpass. All outputs are available simultaneously.

Key to Filter 8's performance is the innovative resonant feedback circuit. By increasing the resonance, all outputs will resonate at the filter frequency, without any low frequency response loss. At higher resonance levels, self-oscillation is achieved, turning the module into an excellent 8-phase sine wave voltage controlled oscillator (VCO) with temperature and switchable gain compensation, low distortion, constant amplitude and accurate frequency tracking over at least 5 octaves. At sub-audio frequencies, Filter 8 can function as an 8-output voltage controlled slew modifier or 8-phase low frequency oscillator (LFO).

Simultaneous exponential and linear frequency modulation is possible, for classic FM tones or chaotic modulation. A hold feature is also provided, 'freezing' the output voltages manually or under gate control. This is useful for halting modulations, or as a sync-like effect at audio frequencies. The dedicated 'ping' input allows you to easily create crisp percussive sounds with different timbres.

While rooted in the legacy of classic synthesisers, Filter 8 provides a new approach to musical signal generators and modifiers: instead of simply a VCF, VCO, slew modifier or VCLFO, a single analogue module can now be any of those, and anything in between.

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: Any signal can be expressed in terms of a few parameters: frequency, phase, amplitude and timbre. It is through modulation of these aspects that synthesists create electronic sound. With Generate 3, it is now possible to create a signal and control all its parameters by through-zero modulation within a single 12 HP wide module.

Everything starts with the exceptionally precise triangle-core voltage controlled oscillator (VCO) at the module’s heart. Through-zero linear frequency modulation (FM) enables rich yet pitch-stable FM sounds, by allowing the oscillator to run backwards into ‘negative frequencies’.

The resultant triangle wave is then processed by the through-zero phase modulator, providing a total phase shift range of 900°. Phase modulation offers an interesting alternative for FM, as it enables deep FM-type tones without actually changing the oscillation frequency.

The timbre of a signal is determined by its harmonic content. This full set of harmonics can be grouped into three main parts: the fundamental, even and odd harmonics. Generate 3’s harmonics generator separates out these three timbral ‘channels’. By adjusting their relative amplitudes, a vast array of different waveforms can be created, including but not limited to the classic sine, saw and square waves.

While the amplitudes can be adjusted manually, each timbral channel supports through-zero amplitude modulation, also known as balanced or ring modulation. When audio-frequency modulation signals are applied, the harmonics become ‘split’, enriching the spectrum.

In addition to all the usual analogue synthesis techniques, the extensive set of modulation options makes Generate 3 especially suited for exploring multiphonic synthesis: a monophonic source creating a complex timbre, much like throat singing, yet by electronic means.

Notes: By combining a mixer and four VCAs in a single module, Mix 3 manages to provide a unique combination of compact size and functionality in just 6 HP. High-end signal paths ensure extremely low noise and distortion, wide headroom and precise gain control, despite the small form factor.

Each of the three main channels has an exponential response, which is more natural for audio than linear, as it matches the human hearing. However, all signal paths are DC-coupled, so control voltage (CV) signals can be processed as well.

What truly sets Mix 3 apart from other compact mixing modules are the three CV inputs, providing voltage control over the signal levels. This even allows you to go beyond unity gain and reach up to +20 dB of amplification. Once a CV input is used, the corresponding channel knob becomes a CV attenuator.

When clipping, Mix 3 does so in a clean, symmetrical way. This yields a very pure overdriven sound, only containing odd harmonics, and allows the module to be used as a triple voltage controlled distortion.

Additional features include audio indicator LEDs, a fourth auxiliary input, voltage control over the output level and a line output jumper setting.

Notes: A multi-VCA module on steroids, the Morph 4 is designed as a modulation hub for an entire Eurorack system, capable of working in coutnless different ways. Proper versatile business.

Supplier's Notes:
Modulation is the core concept of modular synthesis: parameters changing over time, adding movement and musical interest to what would otherwise be merely static sounds. Being able to control the amplitude of signals throughout a patch is therefore essential, and one can never have too many voltage controlled amplifiers (VCAs).

Designed as a fully-featured modulation hub for Eurorack synthesisers, Morph 4 takes the basic concept of the multi-VCA module to the next level.

Four linear amplitude modulators are controlled by a master 'morph' parameter. The response of each modulator to this parameter is completely variable, both manually and under voltage control, and can be overridden if desired. Each response is triangular, with the 'position' parameter setting the maximum point along the morph axis, while 'span' determines the width of the triangle's base.

In addition to separate signal inputs and outputs, a variety of combined outputs is available as well: A+B, C+D, add (unity gain) and averaging mixes, and instantaneous minimum and maximum. Input normalisation makes it easy to send the same signal to multiple modulators, while output and modulator response LEDs provide essential visual feedback.

The combination of master control, fully flexible modulators and multiple combined outputs creates a module truly embodying the spirit of 'patch programmable' modular synthesis. Use Morph 4 as a voltage controlled mixer, dual crossfader, dual panner, interpolating scanner, interpolating distributor, quad VCA, quadraphonic controller, slope modifier, rectifier, complex waveshaper or something in between any of those- the choice is yours.

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: Designed with and for performing artists, Switch 4 delivers a hands-on signal switching and routing solution for your Eurorack modular synthesiser.

Quickly mute audio signals, trigger envelopes live, select modulation sources on the fly... With custom dual-action toggle switches, an intuitive interface and sturdy construction, Switch 4 will prove just as useful on stage as in the studio.

The bottom switching section includes four lever-actuated toggle switches, to make or break the signal path between the inputs and outputs. These switches feature a dual action: latched upwards, momentary downwards.

The four input signals are also sent to the top routing section, where two rotary switches allow you to select the signals to be sent to the matching outputs. Here you'll also find dual-action toggle switches, for added versatility.

Finally, all signal paths are buffered, avoiding signal cuts when shorting a jack during patching or severe loading effects when driving many inputs. The high-end components provide exceptionally low noise and distortion, so Switch 4 can reliably process audio, control voltages and gates/triggers.