This is a design circuit for a type guitar effect. This circuit can be used as delay, reverb or echo because this circuit is use time manipulator. It uses two PT2399 delay integrated circuits to archive up to 600ms delay. Also, with the help of 4 analog switches, the internal configuration of the pedal can change: placing the PT2399 delay chips in series or parallel and adding extra features. This is the figure of the circuit;
This circuit
is is a programmable Arduino based
Delay/Echo/Reverb guitar pedal. The
code for the Arduino chip is programmed
in C and it is Open-Source, so users can re-program the functionality or add
new effects and share them in the forum. There are 9 effects included by default in the pedal: short
delay, delay, echo, reverb, tap
echo, chorus, telegraph, accelerator, and psycho. The schematic and bill
of materials are public,
the circuit was designed using easy-to-find and through-hole components.
This is the Time Manipulator Specifications:
- True Bypass.
- Based on Arduino
UNO ATMEGA328P-PU (8MHz, 1KB RAM) microcontroller.
- Analog
input/output stages using MCP6002 operational amplifiers.
- Interface:
- 1 Mix knob
(blends dry and wet signal)
- 1 Tails Knob
(adjust the number of echo repetitions)
- 1 Tap
foot-switch (programmable)
- 1 3PDT True Bypass foot-switch
- 1 Encoder knob +
Push Button
- 2 x Dual color
LEDs (programmable).
- Connectors:
- Input Guitar
Jack, 1/4 inch unbalanced mono, Zin=1MΩ.
- Output Guitar
Jack, 1/4 inch unbalanced mono, Zout=0.1Ω.
- Power supply:
standard 9V Boss connector (center tip positive)
The main tasks of the
circuit parts are:
- Power Supply: generates
energy (+9V and +5V) and bias voltage (+4.5V) for all the circuit.
- The Input Buffer is
an op-amp with gain=1. It will present a high input impedance (Zin=1MΩ)
and prepare the signal for the rest of the circuit.
- Dual PT2399 Delay Stage: The two PT2399 in the classic Delay configuration can
create a delay from 30 to 600ms approx.
- Arduino Controlled Current Sink: The Arduino microcontroller controls the amount
of delay with a PWM signal. The op-amp current sink is used to transform
the PWM into current thus delay that the PT2399 will have.
- The Output Adder: it will give a low output impedance to preserve
the sound quality on the pedal chain. Its main task is to blend the original guitar signal
together with the different delay paths or "taps".
