Intro:
This phaser is a version of the Tau-Pipe-Phaser project of Juergen Haible. So please see his project site for further details.
But here are some details which are "specials" of my module.
Circuit:
1.) Power supply
I built this phaser as a module for my Formant modular, not as a stand alone device. So I omitted the components of the power supply of the original phaser like the voltage regulators, the fat capacities and some other parts because I used the supply of my modular.
2.) Transistor arrays
I used the CA3086 array for the phase shifters. The original phaser works with the CA3046. I compared the sound of my phaser with the sound examples provided by Juergen Haible and could not hear any differences.
3.) Tempcos I did not use any temperature compensating components. They were used by Juergen's version to adapt the behaviour of the phaser (pikes and drops) according to the V/Oct characteristic (which is the basic function of the input signal also) to achive a kind of "sound tracking".
A standard resistor does this job well enough.
4.) Resonance I reduced the input resistor of the resonance stage from 220k to 180k ( a hint of Juergen Haible) to increase the resonance up to self oscillation. This provides additional interesting sound effects around this point and supports V/oct calibration via using the phaser as a VCO.
Frontend:
The phaser has
- a signal input with level pot
- a V/Oct control voltage input with level pot
(This signal equalizes the sound behaviour of the phaser over several octaves of the input signal) - a control voltage input for voltage controlled phasing with level pot
- two LEDs for displaying the phase shifting process (initiated by the built in triangle oscillator)
- a speed control for the built in triangle oscillator
- a pot for manual phase shifting with output of the manual determined voltage for phaser cascading
- a mixer for oscillator based or manual and voltage controlled phase shifting
- a signal output with level pot
- an auxiliary output poviding the input signal as reference for stereo output
- a level pot for resonance control up to self osillation
- a switch for high pass filtering of the phaser control voltage (for smoothing the sharp jumps of an LFO sawtooth for instance which can be heard as ticks in the output signal)
- a switch to choose phaser or (the more moderate) phaser vibrato module function
- a switch for inverting the effect signal (creates another output spectrum with invrted high and low frequncies)
Board of the phaser:
Complete module:
Hints
please see Juerge Haibles project site for details.
Sound example
Phaser
see also Juergen Haibles project page