We’ve got a hunch that ‘ochd expander’ will be the go-to name for this new modulation powerhouse, but it’s fun to know the technical name is a simple maths function: 8+4^2. Eight + four squared. Eight + sixteen. Twenty four modulation sources.
“Let’s dive in.”
øchd is by far and away DivKid’s most popular module. It’s only 4HP wide and boasts 8 ‘free-running’ triangle LFO outputs & a master rate control via potentiometer or CV.
What does “organic drift” mean in øchd’s official module name anyway?
The LFOs aren’t tuned to specific frequency ratios and divisors. Instead, they were tuned by ear – presumably four of them, Ben and Jason’s – for ideal spread across the frequency spectrum (as the independent LFO cores run from fastest at the top to slowest at the bottom) and general musicality.
To put the øchd’s popularity in context, it is currently in over 30,200 ModularGrid racks. Mutes, the first module from DivKid and second most popular, sits in just over 8300 ModularGrid racks. The SSF RND STEP sits in a close third with almost 7600 ModularGrid racks.
When you combine the totals of second and third place, they amount to just over half of øchd’s popularity.
øchd Expander [ø]4^2
After a few years and tens of thousands of patches it seems that 8 outputs and standard triangle LFO shapes are too limiting for Ben and the Instruo team.
The new øchd expander catapults the number of outputs to 24 modulation sources. From rectification to “slow noise,” let’s delve deeper into the new 4HP expander and explore the vast modulation opportunities it enables.
øchd’s been a mainstay in our rack since the 2019 drop, so we’re excited to get a quick overview from Instruo before moving into [ø]4^2’s features.
Launched in 2019 and designed in collaboration with Ben “DivKid” Wilson, the Instruō øchd has set a standard for compact and versatile modulation sources which can now be seen across thousands of eurorack systems. The Instruō [ø]4^2 adds 16 outputs and 4 new sets of functionality to øchd’s normal operation.
øchd Expander Features
Remarkably, Jason and the engineering team wedged 16 jacks within just 4HP, surpassing the previous Instruo record set by their eãs logic module with 14 jacks.
In the usual Instruo style, the front panel features thoughtfully designed iconography, providing a quick visual reference for each quad-set of outputs.
Speaking of, let’s look at those output blocks shall we? The expander features:
- 4x full wave rectified unipolar positive LFOs
- 2x Analog diode logic pairs (AND/Min and OR/Max)
- 4x Cascading stochastic trigger signals
- 4x R-2R 4-bit logic random voltage sources (slow noise)
Triangle-only no more!
As you watch DivKid’s demo video, the scope shows some really exciting modulation possibilities and unique trace lines vs. the free running bipolar triangle LFO shape(s).
Let’s dig further into each block.
Wave Rectification Block
Rectifier circuits come in two flavors: half-wave rectifiers and full-wave rectifiers.
Half-wave rectifiers slice or zero out the negative half of the waveform, leaving 0V gaps between the positive voltage. Full-wave rectifiers flip the negative portion of the waveform into positive voltage, filling in the voltage gaps and creating a consistent positive signal at twice the frequency.
øchd Expander uses the latter approach, taking all odd LFOs (the ones on the right) and mapping them to the top quadrant. You now have 12 total LFOs: 8 bipolar triangle LFOs from øchd and 4 unipolar LFOs of the expander.
Here’s a little fun fact about the LFO frequencies from DivKid:
“As no øchd LFO is double/half of another LFO you get 4 new LFO speeds from the full wave rectifiers too. 12 rates of LFOs, nuts!”Ben ‘DivKid’ Wilson
Diode Logic Pair Block
The second quadrant houses two separate analogue diode logic pairs.
What does that actually mean in English? It sounds complex, but isn’t that bad once you look at the logic functions.
The circuits follow a combination of OR/AND logic.
The top two jacks (MAX) will always take the higher signal of the two LFOs. The bottom two jacks (MIN) will always take the lower signal of the two LFOs.
The left-side, vertical pair of logic outputs map to LFOs 2 + 3 respectively on øchd, so they will be at much higher rates. The right-side, vertical pair of logic outputs map to LFOs 6 + 7 and will run at slower rates.
At any given time, one of the two LFOs is live in each of the four outputs, creating interesting and disjointed voltage peaks across the +/- 5V range.
Whew. Does that help clean any of this up? We’re excited to see this block in action, as it breaks synchronicity with the main 12 LFOs and has the potential to add unique layers of movement to patches.
Cascading Stochastic Triggers Block
We now move from bipolar, unipolar, and melded LFOS and enter the realm of triggers. Stochastic triggers to be precise.
This block takes all even LFOs (the left-side ones) from øchd and analyzes their rising edge to create ~8ms trigger signals.
LFO 2 maps to the top-left, LFO 4 maps to the top-right, LFO 6 maps to the bottom-left, and LFO-8 maps to the bottom-right on the trigger quadrant.
If you patch the triggers out individually, you get 4 separate but consistent streams. Leave the upper LFOs unpatched however and they normalize or “cascade” down to create these merged and mixed stochastic rhythms.
You can get a combo of LFOs 2+4 in the top-right jack, a combo of LFOs 2+4+6 in the bottom-left jack, and a super combo of LFOs 2+4+6+8 in the bottom-right jack.
Normalization, you’ve done it again.
R-2R 4-Bit DAC Block
We’re not going to try and paraphrase this one. Instruo, take it away:
R-2R ladder circuits are used to create simple digital-to-analog converters (DACs). This makes it possible to generate random-stepped voltage signals at the fourth set of 4 outputs.
Ok, so we’ve finished the main course of LFOs / triggers and it turns out dessert is 4 separate +/-5V stepped voltage signals? A pleasant surprise and an ingenious way to fit this type of modulation source into such a small footprint.
øchd Expander Price
We thought at $200 the øchd was already competitively priced, but Jason specifically emphasized the significance of cost for the new expander, aiming to pair it with as many øchds as possible.
Cutting the price nearly in half? Sounds like they’re on the right track.
You can grab the øchd expander now for just $109.
øchd Expander Links
- øchd Product Page
- øchd Quick Start Guide
- øchd Manual
- øchd on ModularGrid
- øchd at Signal Sounds
- øchd at Perfect Circuit
Check out the video for beers, pretzels, an entire case of øchds, and some great insight into the functionality and development of the øchd expander.
Hoped you liked digging in to this new modular powerhouse from Instruo and DivKid.
Now all we need is 24 attenuators in 8HP. What do you think Instruo? Let’s make it happen! ; )