joranalogue-collide-4

Joranalogue Collide 4

Quadrature spectral computer

20 HP Eurorack module

An analogue Eurorack synth voice and audio processor based on a dual-phase lock-in amplifier. A self-oscillating filter, through-zero quadrature oscillator, and two balanced modulators support synthesis, frequency shifting, percussion, and signal analysis, with individual, sum, difference, magnitude, and phase outputs.

Features

  • The differential preamplifier subtracts Negative Signal Input from Positive Signal Input. Both inputs are AC-coupled, rejecting DC with a 16 Hz cutoff.
  • Preamplifier Range selects stepped gain from -20 dB to +30 dB, with 0 dB unity gain and an off position that mutes the input. Attenuation helps prevent filter clipping; amplification can deliberately overdrive the filter input.
  • Remember to keep input signals within +/-12 V. The -20 dB preamplifier setting does not make the module suitable for higher input voltages.
  • Input Level/Overload glows white with brightness following the input section's output amplitude. Red indicates clipping anywhere in the preamplifier, filter, or gain VCA. These overloads produce audible distortion without damaging the module.
  • Filter Centre CV Input tracks at 1 V/octave. The temperature-compensated filter can serve as a sine oscillator when self-oscillating; maximum resonance and medium width give the best pitch tracking.
  • Filter Width moves the highpass and lowpass poles apart. Minimum width gives a two-pole bandpass response with -6 dB at the centre frequency; wider settings approach unity gain there. With centre frequency halfway and width maximum, the passband spans 22 Hz to 22 kHz. Filter Width CV Input responds at approximately 1 V/octave.
  • Sufficient Filter Width and Filter Resonance produce sine-wave self-oscillation. The resonance scale mark indicates the typical threshold at maximum width. Narrower bandwidth reduces resonance, and oscillation amplitude can vary with temperature. At Filter Resonance CV Input, +5 V corresponds to maximum resonance.
  • Filter Gain controls a post-filter amplification VCA from unity gain to +60 dB. Deliberate clipping adds overdrive and can reshape sine waves toward harmonically rich square waves.
  • Filter Gain CV Input modulates gain at 12 dB/V through the bipolar Gain Modulation Depth control. CV extends the VCA range to -20 through +100 dB; combined with the preamplifier, the total input gain range is 130 dB.
  • Monitor Output provides the preamplifier, filter, and gain VCA signal before balanced modulation, allowing the input section to be used and monitored separately.
  • In audio range, with Oscillator Fine Frequency centred and Oscillator Symmetry maximum, Oscillator Coarse Frequency spans 22 Hz to 22 kHz. Fine tuning covers 5% of the coarse range, equivalent to six semitones in audio range.
  • Oscillator V/Oct Input responds exponentially at 1 V/octave in audio range and approximately 0.66 V/octave in low range. Oscillator Exponential FM Input has its own bipolar depth control: centre gives zero modulation, with opposite polarities on either side and maximum sensitivity of +/-1 V/octave in audio range.

Controls & Jacks (54)

  • Oscillator Fine Frequency— Fine oscillator tuning with a range equal to 5% of the coarse control's range, corresponding to six semitones in audio mode.
  • Filter Resonance— Sets filter feedback and resonance, emphasising the centre frequency and reaching sine-wave self-oscillation at sufficient width and resonan
  • Oscillator Coarse Frequency— Sets oscillator frequency over 22 Hz–22 kHz in audio range with Fine Frequency centred and Symmetry at maximum.
  • Oscillator Frequency Range— Selects audio-rate VCO or low-frequency VCLFO operation. Audio range also AC-couples the through-zero FM input; low range leaves it DC-coupl
  • Filter Centre Frequency— Sets the variable-bandwidth filter's centre frequency from 22 Hz to 22 kHz in Free mode.
  • Oscillator Exponential FM Depth— Polariser for exponential FM, with zero depth at the centre and opposite modulation polarities either side. Maximum sensitivity is ±1 V/octa
  • Filter Gain— Sets post-filter VCA amplification from unity gain to +60 dB; higher settings can deliberately produce clipping and overdrive.
  • Time Constant— Sets both two-pole detector lowpass-filter cutoffs together. Turning anticlockwise lowers cutoff, smoothing toward the average DC value; clo
  • Gain Modulation Depth— Bipolar modulation-depth control for the Filter Gain CV Input, allowing positive or inverted gain modulation around a zero-depth centre posi
  • Filter Width— Sets the separation of the filter's highpass and lowpass poles, from a narrow two-pole bandpass response to a broad passband covering 22 Hz–
  • Oscillator Through-Zero FM Depth— Sets linear through-zero FM depth with a bipolar response; positions left of centre invert the modulation signal.
  • Preamplifier Range— Rotary switch selecting coarse preamplifier gain from −20 dB attenuation to +30 dB amplification, with 0 dB unity gain and an off position t
  • Oscillator Symmetry— Sets the oscillator's through-zero FM symmetry. The centre gives symmetrical TZFM; either extreme gives in-tune asymmetrical modulation, req
  • Filter Free/Track— Selects freely adjustable filter centre frequency or tracking of the through-zero oscillator frequency.
  • Filter Width CV Input— Modulates the filter bandwidth at approximately 1 V/octave.
  • Oscillator Exponential FM Input— Exponential frequency modulation input controlled by the bipolar Exponential FM Depth knob; maximum sensitivity is ±1 V/octave in audio rang
  • Filter Centre CV Input— Modulates the variable-bandwidth filter's centre frequency at 1 V/octave, including accurate pitch control when the filter self-oscillates.
  • Filter Gain CV Input— Modulates post-filter gain at 12 dB/V through the bipolar Gain Modulation Depth control, with an achievable gain range of −20 to +100 dB.
  • Ping Input— A rising edge exceeding +3 V fires an internal transient generator that excites the input filter for percussive sounds.
  • Difference Output— Outputs X′ − Y′. With the Hilbert network enabled, this provides the frequency-shifted sideband opposite to the sum output.
  • Oscillator V/Oct Input— Precision exponential oscillator frequency control at 1 V/octave in audio range and approximately 0.66 V/octave in low range.
  • Time Constant Frequency Range— Selects the common detector lowpass-filter cutoff range: 22 Hz–22 kHz in Audio or 150 mHz–150 Hz in Low.
  • Time Constant CV Input— Modulates both detector output lowpass-filter cutoff frequencies together at approximately 1 V/octave.
  • Negative Signal Input— Inverting input of the differential preamplifier, subtracted from the positive input. AC coupling rejects DC with a 16 Hz cutoff.
  • Monitor Output— Outputs the signal after the preamplifier, variable-bandwidth filter, and gain VCA, before the Hilbert network and balanced modulators.
  • Y Signal Input— Overrides the normalled input-section/Hilbert signal feeding the Y balanced modulator. The multiplier computes Y′ = Y × Q ÷ 5 V before outpu
  • Hilbert Transform— Selects bypassed Hilbert processing, feeding identical signals to X and Y, or the enabled network, producing a 90° phase difference for freq
  • Oscillator Through-Zero FM Input— Linear through-zero frequency modulation input with bipolar depth control. It is AC-coupled in audio range to reject modulation offsets that
  • Positive Signal Input— Non-inverting input of the differential preamplifier. The negative input is subtracted from this signal; AC coupling rejects DC with a 16 Hz
  • Filter Resonance CV Input— Modulates filter resonance; +5 V corresponds to maximum resonance.
  • X Signal Input— Overrides the normalled input-section/Hilbert signal feeding the X balanced modulator. The multiplier computes X′ = X × I ÷ 5 V before outpu
  • Input Level/Overload— White brightness indicates the input section's output amplitude; red indicates clipping detected anywhere in the preamplifier, variable-band
  • Sum Output— Outputs X′ + Y′. With the Hilbert network enabled, this provides one frequency-shifted sideband; oscillator frequency direction determines w
  • Q Reference Input— Overrides the normalled oscillator Q reference for the Y balanced modulator. It is interchangeable with Y for multiplication; a constant +5
  • Oscillator I Output— In-phase oscillator output: a nominal 10 Vpp low-distortion sine wave, usable at audio or LFO rates and separated from Q by 90°.
  • Oscillator Q Output— Quadrature oscillator output: a nominal 10 Vpp low-distortion cosine wave, usable at audio or LFO rates and separated from I by 90°.
  • Magnitude Output— Outputs the nonnegative vector magnitude √(X′² + Y′²). The analogue computation handles DC and audio-rate signals for measurement and wavesh
  • I Reference Input— Overrides the normalled oscillator I reference for the X balanced modulator. It is interchangeable with X for multiplication; a constant +5
  • Phase Output— Outputs the full-circle vector angle derived from X′ and Y′ at 18°/V over −10 to +10 V. It responds to DC and audio-rate signals and wraps a
  • X′ Output— Outputs the X balanced-modulator result after its two-pole lowpass filter, including audio signals or the average DC component used for lock
  • Y′ Output— Outputs the Y balanced-modulator result after its two-pole lowpass filter, including audio signals or the average DC component used for lock
  • Magnitude Signal Level— Separate output indicator visualising the nonnegative magnitude voltage.
  • Difference Signal Level— Separate dual-colour indicator visualising the X′ − Y′ difference output voltage.
  • Sum Signal Level— Separate dual-colour indicator visualising the summed X′ + Y′ output voltage.
  • Phase Signal Level— Separate dual-colour indicator visualising the phase output voltage.
  • Y′ Signal Level— Separate dual-colour indicator visualising the Y′ output voltage.
  • X′ Signal Level— Separate dual-colour indicator visualising the X′ output voltage.
  • X′ Null Calibration— Front-accessible trim potentiometer balancing the X modulator to minimise oscillator bleed at X′ when no input signal is present.
  • Oscillator Q Polarity— Displays instantaneous oscillator Q voltage, lighting red for positive and blue for negative voltage.
  • Oscillator V/Oct Calibration— Front-accessible trim potentiometer calibrating the oscillator's 1 V/octave pitch tracking.
  • Filter V/Oct Calibration— Front-accessible trim potentiometer calibrating the variable-bandwidth filter's 1 V/octave pitch tracking.
  • Oscillator I Polarity— Displays instantaneous oscillator I voltage, lighting red for positive and blue for negative voltage.
  • Y′ Null Calibration— Front-accessible trim potentiometer balancing the Y modulator to minimise oscillator bleed at Y′ when no input signal is present.
  • Oscillator Amplitude Calibration— Front-accessible trim potentiometer setting oscillator amplitude; calibrate either I or Q to 10 Vpp. An excessively low setting can prevent

How-To Guides

  • Ping the filter
  • Patch a stereo complex oscillator
  • Patch a frequency shifter
  • Patch a dual-tone sine oscillator
  • Patch a percussion synthesiser
  • Calibrate filter pitch tracking
  • Calibrate oscillator pitch tracking
  • Calibrate oscillator amplitude
  • Null the balanced modulators

Explore the interactive Collide 4 panel on BleepDex — tap any control to learn what it does.

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