Tonecoder-sharktooth

A novel effects box

A year or two ago I connected a photocell to a time delay circuit and found that modern light bulbs will modulate the playback frequency. They oscillate at audio frequencies to reduce energy usage but the downside is that it disturbs natural brain function.

Tuning my instrument to the room light (carrier frequency) gave a nice tonal resonance with interesting sideband frequencies. This is essentially fm resynthesis, with the modulator set at fixed frequency.

The pt2399 has a VCO input, so to make a tunable arangement of this you can insert an oscillator directly to modulate the signal. 

I've been designing a box to make use of this effect. After discarding the first circuit board because of noise issues I rearanged the layout

and made two prototypes with various features and concluded with the most simple arangement- two tuning knobs. There is wide range oscillator control- for the carrier, and an attenuator. Its a special effect when full on and but i like to use it almost fully attenuated to enliven the harmonics and tighten the sound of slacktuned guitar.

The box was made from an old rimu door. I hollowed it out enough to house the electronics and cut some iron sheet for the faceplate. The sheet metal got a wee brittle from to much hammering and split on the top edge but otherwise it came together well and it feels nice to hold. The first prototypes had an inlayed plate that I milled with the cnc but I prefer the feel of the iron folded over the wood.

The PT2399 circuit give great depth of modulation and clean sound with some compression. Its still a touch noisy from the internal clock aliasing the modulation oscillator. 

Nightlights

These charge in the day and turn on in the dark. The 1.2 volt battery is boosted by a coil and hf oscilator to power led lights.

Lightswitch

Tiltswitch

This one has the coil oscilator and brass tilt switch

Métamorphoser

-+ Making sound with ambient light +-

Whistles softly in low light, ocean waves in medium light and silent in full sun.

Made from hollowed chair leg and brass sheet.

This guy has a control panel for dialing in ocean baby, radio static and wet cricket in full light.

Light dust/rain to pure white noise depending on light exposure. 

The circuit has very low resistance and begins emiting sound with only a slight glimmer of light(natural or artificial) and goes silent in full sun unless you bring a water based mass close to the left wing which is a capacitive sensor. This makes it sensitive to humidity also.

74hc14 hex inverter with dual transistors and a74hc595 shift register.

 

5 low frequency oscilators set at various rates of charge/discharge create a randomised wave. it is read by a vco in high audible to ultrasonic range range.

this doesn't make sounds but resonates at high frequencies

Daisy chains

Transistor neuron circuit for feedback loops. 

memory loss - echoes

The last of the glitchy pt2399 circuits that I sold previously as the seppuku memory loss, eccodrone and fragment.
The pt2399 is designed to be a karaoke reverb chip but this is less an echo and more of a analog noise generator/effect. The delay is in fact a 44000 bit shift register.
The chip has an internal lowpass, shift register, modulator and demodulator current control and  reset function  that can be used as a comparator with gate delay.
The input signal flows through three paths each having a distinctive tonal effect that is chopped up and displaced depending on feedback balance and delay time. The feedback path goes through a lot of resistance which allows for a floating area where it drifts in and out of oscillation but it means that the critical stages of the turn is caught in the far reaches.

There are rotary controls for feedback and feedback path, clock, input and output voltage.
The toggles are for processing/generator modes and led diode clipping/gate.

This is another take on the pt2399. It has a voltage control input for delay time., feedback loop has a clipping/squishing circuit and the delay is set up to allow control of compression and manipulate the samplenhold of the a/d conversion. Does nice rising triangle oscillations that interact with the input. (input velocity x freq)   It is good for extending sustain and playing very slow music. 

exor

This is a noise generator  made of 2 shift registers and 3 exor gates and 2 high frequency oscillators .
At each pulse, data entered into the shift register is moved along sequentially through eight stages.
Stages 678 of each register are made available for patching.
An exor gate has two inputs. It opens only when one is up and the other is down ; at all other times it will lie low
Comparing nodes on the shift register and recirculating creates noise, patterns, and tones.

Instead of isolating the circuit on a board I glued the chips down on there backs and wired the jack directly to there little legs. There wasn't any resistance. The circuit is very open to environmental effects.
The oscillators have two outputs each as well as little ears for alligators and fingertips..
I made little brass inserts for the bakelite knobs and glued the old insert onto the front to mark the exor.