Aperture Kit

The RYO Aperture is a vactrol lowpass filter and VCA module inspired by the 292 Lopass Gate from the Buchla 200 series modular system.

This is a full kit set in the Eurorack format.

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The RYO Aperture is a vactrol lowpass filter and VCA module inspired by the much beloved 292 Lopass Gate from the Buchla 200 series modular system of the 1970s. However, rather than being a straight up clone, the Aperture is a newly developed and reworked design for eurorack modular synths.

Aperture can be used as a 12dB lowpass filter, a VCA or a combination of the two similar to the 292 but also adds a new switchable resonance circuit. This solution gives you no less than 6 different characteristics!

  • Non resonant lowpass filter
  • Resonant lowpass filter
  • Both: Non resonant lowpass gate
  • Both: Resonant lowpass gate
  • VCA
  • 6dB variety of resonant lowpass gate in the VCA mode with resonance on.

The resonance goes from smooth and twangy to increasingly bubbly and acidic to wild and untamed howling towards the end of the pots range. The self-oscillation also lends itself well to creating kickdrums, toms and other percussive sounds.

The result is a very wide range of sound shaping possibilities, from the classic resonant filter sweeps of east coast to the plucky acoustic timbres of west coast synthesis and everything in between.

Also added is a unique "Klang" function. The Klang input generates a decay slope from a trigger, the shape is very steep in the beginning and quickly smooths out to a nice prolonged ring, resulting in a very natural acoustic sounding tone.The circuit was specifically tailored for this purpose and does not give the same result as just using a decay envelope with the regular CV input. Experimenting with different trigger voltage and length will affect the response of the decay and overall shape. It will also work with other control voltages but will add a falling slew to the signal. Trigger the CV as well as the Klang input at different intervals for simulating the impression of striking a drum or string instrument in different ways.

Finally, the input is AC coupled and has a dedicated attenuator with clipping overdrive towards the end of the pot range for adding a bit of extra bite to the incoming signal. The signal input is scaled for 10Vpp audio signals. The AC coupling comes after the overdrive circuit so you can add offsets to your audio with RYO Ampmix and many other modules to get an asymmetric clipping.

Specs & Downloads

Specs & Downloads

100 RYO
HP 8
Depth 27mm
+12V 50mA
-12V 70mA
+5V No
Additional Resources Build Guide Schematics


Customer Reviews (3)

Very nice moduleReview by Justin
This was a relatively easy build with clear instructions and extra parts included. As other reviewers have said it sounds great and can have quite a bit of character. (Posted on 2/4/2017)
Excellent VCF and VCAReview by Mike Darrol
This kit took about 3 hours to assemble. It is very high quality, easy to calibrate (you can do it by ear if you don't have a scope handy), and sounds great. There is an extra of almost every common passive component. You will have to print the PDF for yourself, no instructions are included. (Posted on 10/3/2016)
Great kitReview by John
Quality parts, decent, clear instructions. They pack extra resistors and other bits in case you lose one. Boards clearly marked with part numbers and orientations, easy to follow. End result has solid feel and nice sound. VCA is clean with no audible bleed-through, VCF has variable feedback for a range of effects, subtle to screaming. Minor glitch with the jacks - mine had the wrong type packed, which Modularaddict quickly resolved. Highly recommended. (Posted on 5/15/2016)

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