Sinc Bucina#

Resonant low-pass gate with variable filter slope, RC envelope generator, and slew


Sinc Bucina is the sequel to one of our first modules, Sinclastic Empulatrix, replacing the clamping VCA with a resonant low-pass VCF and VCA combo. The velocity-dependent Ping input offers classic release-only LPG behavior, while the Gate in offers much more complex slewing, useful for simple ASR envelopes to dynamic modulation. The Envelope out allows the internal envelope to be routed out into a patch for even more versatility and modulation fun.

  • Type: VCFA, envelope generator, slew
  • Size: 4HP Eurorack
  • Depth: 0.8 inch
  • Power: 2x5 Eurorack
  • +12 V: 45 mA
  • -12 V: 40 mA


Sinc -- shortened from Sinclastic from Old English sinc "treasure', from greek clastic 'easily removable' Bucina -- from Latin: "War Trumpet"

"Easily Removable War Trumpet"


Power connector

To power your Noise Engineering module, turn off your case. Plug one end of your ribbon cable into your power board so that the red stripe on the ribbon cable is aligned to the side that says -12 V and each pin on the power header is plugged into the connector on the ribbon. Make sure no pins are overhanging the connector! If they are, unplug it and realign.

Line up the red stripe on the ribbon cable so that it matches the white stripe and/or -12 V indication on the board and plug in the connector.

Screw your module into your case before powering on the module. You risk bumping the module's PCB against something metallic and damaging it if it's not properly secured when powered on.

You should be good to go if you followed these instructions. Now go make some noise!

A final note. Some modules have other headers -- they may have a different number of pins or may say "not power". In general, unless a manual tells you otherwise, do not connect those to power.


illustration of Since Bucina's interface

Momentary button that sends a gate to the Gate in for as long as the button is pressed.
Sets the rise time for the slew. The Attack stage is bypassed if a trigger is sent to the Ping input.
Sets the fall time for the slew.
Sets the LPG's behavior: resonant 6 dB-slope low-pass filter, no filter (just VCA), or 12 dB-slope low-pass filter.
Amplitude-dependent trigger input. Sending a trigger to this input bypasses the Attack stage. Release time is set by the Release knob. Ping input is voltage dependent: a lower voltage trigger will open the VCA and VCF less than a higher voltage trigger, which allows for expressive and dynamic sequencing. 0 V to 5 V; 5 V opens the VCA/VCF completely.
Slew input. Any type of signal can be input here: send a gate to this input for ASR envelope behavior, or send a more complex signal like a voltage sequence in to be slewed, with rise rate set by Attack and fall rate set by Release. A trigger can also be sent here for slightly different behavior from the Ping input; note that since this is a true slew limiter, the duration of the trigger must be longer than the Attack time to open the VCA/VCF completely. Also voltage dependent: a lower voltage will open the VCA and VCF less than a higher voltage. 0 V to 5 V.
Envelope Out
ASR envelope output.
Audio In
Audio into the VCF/VCA.
Audio Out
Audio out from the VCF/VCA.

Input & output voltages#

Ping will trigger starting at 2 V and will fully open the VCFA at 5 V.

Gate in will respond to voltages up to 10 V.

The Envelope output is 0 V to 6 V, depending on Ping/Gate input.

Patch tutorial#

Patch 1
Send a simple oscillator signal to the Audio In. Patch the Audio Out to your mixer. Send a trigger to the Ping input and play with the Release time to create plucky, percussive sounds. Also try sending a more complex oscillator (like the Loquelic Iteritas or Ataraxic Iteritas) for classic "west coast" tones (and beyond)!
Patch 2
Send an audio signal to the Audio In and patch the Audio Out to your mixer. Send a stepped voltage sequence to the Gate In and adjust the Attack and Release times to increase or decrease slewing between steps and create a dynamic, harmonically rich sequence.
Patch 3
Run a trigger into an attenuator (like Sinc Defero) or a VCA and then into the Ping input of Sinc Bucina. Patch an oscillator to the Audio In and the Audio Out to your mixer. Adjust the attenuator or open and close the VCA to hear the different dynamics Sinc Bucina can impart onto a waveform. A static attenuated trigger can be useful to shape the character of Sinc Bucina.

Design notes#

The first design of Sinc Bucina was created soon after Don Buchla's death. Though electronically Sinc Bucina is a distant cousin of the original low-pass gates, it very much draws inspiration from Buchla's pioneering early synthesizer work. This is technically our first analog filter. Sinc Bucina is a simple two pole low-pass filter with a following VCA. All sections are implemented with the SSI2164 VCA. We chose not to use vactrols for practical and environmental reasons, but the envelope generator is a very simple DRC network with a little complexity to give a touch of the vactrol temporal-nonlineary behavior.


We will repair or replace (at our discretion) any product that we manufactured as long as we are in business and are able to get the parts to do so. We aim to support modules that have been discontinued for as long as possible. This warranty does not apply to normal wear and tear, including art/panel wear, or any products that have been modified, abused, or misused. Our warranty is limited to manufacturing defects.

Warranty repairs/replacements are free. Repairs due to user modification or other damage are charged at an affordable rate. Customers are responsible for the cost of shipping to Noise Engineering for repair.

All returns must be coordinated through Noise Engineering; returns without a Return Authorization will be refused and returned to sender.

Please contact us if you think one of your modules needs a repair.

Special Thanks#

  • Don Buchia