ZOIAhuasca — a fuzzed out psychedelic tremolo

While beta-testing firmware 1.13, I was looking for a patch idea to try out some of the new features. It’s one thing to test them in isolated experiments, but I wanted to build something that depended on their specific qualities and see how they performed.

Then I got an email about the last run of Abracadabra Ayahuascas selling out in ten minutes. I had received the sales email, too, but I didn’t see it; I was eating dinner. So, I thought: here is a great opportunity.

**This patch requires firmware 1.13 to function properly**: https://support.empresseffects.com/support/solutions/articles/1000275389-updating-firmware-on-the-zoia

It makes use of:
— Linearly controlled LFOs
— Tap to CV
— The new, improved clock divider (*starred* inside the patch; there was originally a front-page control to cycle through different clock divisions, but it was cut for CPU reasons)

So, this patch attempts to replicate the -functionality- of the Ayahuasca. I’m not going to make any great claims to being able to replicate a fine-tuned analog fuzz circuit. This patch doesn’t. But it does allow some of the things that make the Ayahuasca interesting, including: the modulating of specific parameters (a la CBA dipswitches, except here, there are individual depth controls per modulation lane), a modu-shaped tremolo (which allows for creating a tremolo with two different waveforms on each half of its cycle), expression control over all of these (as an option for the modulation lane), and the option to choose between standard tremolo and harmonic tremolo (the Ayahuasca has a “both” option, but honestly, I have a Gravitas, and I really don’t hear a lot of difference with this; I had a “both” setting, but it got scrapped for CPU reasons).

This means you can create dual tremolos (modulating the input or output gain of the fuzz), dual harmonic tremolos (modulating the color control — the Muff tone stack is, in essence, an unmodulated harmonic tremolo of a kind), tremolos that ramp up and down in speed, tremolos that shift around (as sway is modulated), etc. etc. Lots of cool sounds.

This is a rarity for me, but the patch is mono: left input to left output.

(There is probably enough CPU overhead that you could add a stereo input and output and sum to mono, then split to dual mono. If you would like to, connect the additional input to the fuzz input on the second page, and connect both VCAs on the third page to the additional output.)


Left stompswitch — tap tempo (clock divider is starred); the rate control will override the tap tempo, the tap tempo will override the rate control — you can adjust either one, but as soon as you adjust the other, it will be given control over the rate of the tremolo

Middle stompswitch — feedback on/off; there is a feedback circuit somewhat in the style of a Fuzz Factory, that feeds the output of the circuit back into its input — it can get quite hairy and loud and oscillate and do other fun stuff

Front page:

Each control across the top has a “Mod on” button and a “Mod depth” control. The “Mod on” button works like a dipswitch — turn it on to modulate this control. The “Mod depth” control is bipolar — it can be set to negative or positive amounts. A setting of -1 will sweep the control from its current position to the lowest position. A setting of 1 will sweep the control from its current position to its highest position. Anything in between these will be different depths of the two extremes.

Input — input gain of the fuzz

Output — output gain of the fuzz

Color — tone control for the fuzz. The tone stack is based on the Ram’s Head Big Muff and therefore features the “mid-scoop” found in Muff pedals. If you would like to try different tone stacks, the filters used to create the tone stack are found on the second page, immediately following the fuzz. I used this site as a resource for setting the frequencies; it also features other famous iterations of the Muff tone stack:


Rate — controls the rate of the tremolo (unless controlled by tap tempo; see above)

Depth — depth of the tremolo

Sway — controls the centerpoint of the tremolo LFO — move toward 0 and the rise will be short and the fall long, move toward 1 and the rise will be long and the fall short

Beneath these:

Modushape — these are UI buttons that will change color as you cycle through the different halves of the tremolo waveform: mango — sine; lime — triangle; aqua — square

A pixel beneath this will show the rate, shape, and depth of the tremolo LFO.

On the left side of the page are controls for the “Mod” switches.

Mod rate — sets the rate of modulation

A pixel beside this will show the rate and shape of modulation.

Mod shape — this is a UI button that will change color as you cycle through different mod options: orange — triangle; green — square; blue — random

A fourth modulation option exists beside the mod shape button: Expression. This will route the expression input to any of the active modulation lanes and use the depth controls assigned to them, just like one of the LFO shapes would.

Beneath these:

Stand(ard) or harm(onic) — a button that allows you to choose between a standard tremolo and a phasey harmonic tremolo

If you would like to adjust the cross-over frequency of the harmonic tremolo, the filters used for it are found on the third page, just below the panner. They have been *starred* as well for convenience.

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  • Category: Effect
  • Revision: 1.0
  • License: Creative Commons Attribution Share Alike 4.0
  • Views: 391
  • Modified: 3 weeks ago
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One comments on “ZOIAhuasca — a fuzzed out psychedelic tremolo
  • Christopher H. M. Jacques on said:

    I forgot to mention in the patch notes: It also responds to MIDI clock, but MIDI clock will override both tap and rate control of the tremolo.

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