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Percussion Sensors

PAiA article - Percussions Sensors - Converting oscillatory signals

The signals produced by most percussion sensors will require some processing before they’re useful as triggers.  Usually this means converting an oscillatory signal into a single unambiguous pulse that is appropriately scaled to carry the widest possible range of velocity information to the circuit being controlled.  The circuitry in the diagram below performs this function.…

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MIDI2CV8 to Drum Tone Board Connections

PAiA Drum Tone Board Connections - Diagram

Power for the Drum Tone Board can be tapped from the MIDI2CV8 aux. power connections using the parts shown to the left.  The nominal “+5” bias line of the Tone Board will be more like 7 or 8 Volts using the values shown and the Tone Board will like this fine (better than 5V, actually).…

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Drum Tone Oscillators

PAiA Analog Synthesizer Drum Tone Oscillators

The circuit shown is the most interesting of several drum oscillators on an analog sound board that appeared as part of an article in the June 1993 issue of Electronics Now. Like most drum tone oscillators, the circuit is a very high Q resonant filter that is only slightly overdamped and on the verge of…

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Scott’s Vocoder Clarifier Mod

This modification to the PAiA 6710 Vocoder increases clarity and virtually eliminates noise by buffering the IN1 and IN2 level controls from the sixteen filters they feed.  Each buffer drives its own filter which prevents loading of the level controls.  This gets more signal to the filters and eliminates interactions between them.  Also, the value…

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FatMan Analog Synth – Frequently Asked Questions

FatMan Analog MIDI Synth

What kind of amp should I use? Any kind.  Guitar and instrument amps are fine as are “hi-fi” amps.  At the bench we often use small single unit amp/speakers from Radio Shack. Do I have to burn a PROM? No. The electronics kit includes a burned prom.  The code is available on our website for…

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Theremax Schematic

The Theremax manual goes into much greater detail than the following brief design analysis. Hand and body motions in proximity to the sensing antennas produce frequency changes in a Hartley oscillator operating at approximately 750kHz.  The signal from this variable oscillator is mixed with a constant reference frequency in a ring modulator and the result…

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Theremax Tuning Revised

A quick tuning method (no test lead jump used): Back all four tuning slugs fully out (ccw).  Turn L1 and L4 one turn in.  Connect the audio output to an amp/speaker and set the Volume control R83 to about 3:00.  Set the Velocity to max.  Slowly adjust L3 inwards through it’s range listening for a…

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Theremax Controls

Controls Pitch & Volume Trim – these control provide a vernier null of the reference and variable heterodyneing oscillators in the Pitch and Volume control circuitry. Pitch CV – controls the range of control voltage produced in response to hand proximity to the vertical pitch antenna on the right side of the instrument.  Clockwise rotation increases range…

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Theremin FAQ

MODS and More What is the range of the theremax. One octave? Two octaves? How hard is it to build my own case? Does the bottom have to be metal? Can I use the PAiA MIDIBrain with my Theremax? My oscillators drift and I have to keep tweaking the tuning … Can I get a…

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