Akashic Guitar effects circuit lookup
GAINRESOLUTIONSAMPLE RATEVOLUME

Enclosure not stated · 4 knobs

Tagboard Effects

Catalinbread HeliotropeVerified

Based on the Catalinbread Heliotrope· 2 other boards clone it

Category
Distortion
Controls
Gain · Resolution · Sample Rate · Volume
Build
Vero· 17×18· 20 cuts, 6 links
Layout
Verified · Tagboard Effects marks it as built and working
Tags
Catalinbread, Distortion, Fuzz, Noise, Octave

From the post

Info from Catalinbread about the original:

What do you call an effect that isn’t quite a Bit Crusher, or an Octave, or a Harmonizer, or a Ring Modulator, or a Lo-Fi dirt box/fuzz – but a bit of a blend of each?

Yeah – we don’t know either, so we came up with “Harmonic Pixelator”.

The Heliotrope is an "analog bit crusher" of sorts. Since there is no analog to digital conversion happening it isn't a true bit crusher, hence the name "Harmonic Pixelator". It works with guitar, bass, keyboards, etc. We designed the pedal to be intuitive and easy to use even though what it is capable of sonically is actually quite complex and varied.

The Heliotrope can be powered from a 9v-18v adapter or a 9v battery. At 18v you’ll notice more output volume and headroom is available.

The controls work like this:

Your instrument of choice (aka: Program Frequency) feeds the Heliotrope an input signal. From it is subtracted the Carrier Frequency. The Carrier Frequency is set by the Hi/Lo switch and the Sample Rate knob.

These are the rough ranges of the frequencies governed by the Hi/Lo switch: Hi: 1.44kHz - 6.66kHz Lo: 333Hz - 1.58kHz

So if the Carrier Frequency is tuned using the Hi/Lo switch and the Sample Rate knob to around 440Hz and you play a high E string at around 320Hz the output is roughly 110Hz or an A String. With a little thinking you can break down all these intervals and harmonize with the pedal - or you can just have fun and set it to an interesting resonant sound and see where it takes you.

The Resolution control determines the duty cycle or the ratio of on to off time of the Carrier Frequency. The effect of this control is somewhat like focusing the lens on a camera, you can make it as sharp or as blurry as you’d like.

Volume makes it go loud.

Gain distorts and compresses the signal. You can get a decent amount of grit and fuzz out of it for more squarewave synthy type stuff.

Enough math – let’s rock this thing!

Schematic

This is a board layout, a drawing of where each part goes, and the post may link the schematic it was drawn from. Open the layout at Tagboard Effects. No KiCad fragment has been drawn for this circuit yet.

Parts list 28 rows

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RefValueNormalizedTypeNotes
Resistors 9
×247R47read from the layout by eye
×31K1kread from the layout by eye
×12K2kread from the layout by eye
×13K33.3kread from the layout by eye
×14K74.7kread from the layout by eye
×410K10kread from the layout by eye
×112K12kread from the layout by eye
×147K47kread from the layout by eye
×41M1Mread from the layout by eye
Capacitors 7
×14n74.7nread from the layout by eye
×122n22nread from the layout by eye
×247n47nread from the layout by eye
×14u74.7uelectrolytic; read from the layout by eye
×210u10uelectrolytic; read from the layout by eye
×147u47uelectrolytic; read from the layout by eye
×2100u100uelectrolytic; read from the layout by eye
Diodes 4
D11N41481N4148read from the layout by eye
D21N41481N4148read from the layout by eye
D31N41481N4148read from the layout by eye
D41N41481N4148read from the layout by eye
Transistors 1
Q12N54572N5457JFET; read from the layout by eye
ICs 2
IC1TL072TL072read from the layout by eye
IC2LM741LM741read from the layout by eye
Potentiometers 4
GainA100KA100kPotentiometerread from the layout by eye
ResolutionB100KB100kPotentiometerread from the layout by eye
Sample RateB1MB1MPotentiometerread from the layout by eye
VolumeB100KB100kPotentiometerread from the layout by eye
Switches 1
SwSPDTSPDTtoggle, 2 position; read from the layout by eye

Other boards based on the Catalinbread Heliotrope