ELECTRONIC SOUND MODIFIERS AND SIGNAL PROCESSORS FOR MUSICAL [INSTRUMENT, NAMELY FOOT PEDALS FOR USE WITH ELECTRONIC MUSICAL INSTRUMENTS; ENVELOPE-CONTROLLED FILTER, PHASE-SHIFTER, OCTAVE-DIVIDER, EQUALIZER, TREMOLO DEVICE, COMPRESSOR, LIMITER, RING MODULATOR, CHORUS EFFECT UNIT, FLANGING EFFECT UNIT, ECHO UNIT, REVERB UNIT, ROTATING SPEAKER, DISTORTION, VOLUME PEDAL, EXPRESSION PEDAL, FILTER PEDAL, INSTRUMENT TUNER, MIXER, PRE-AMPLIFIER, AMPLIFIER, HEADPHONE AMPLIFIER, SPEAKERS, DIRECT BOXES, PATCH BAY, CABLES, POWER SUPPLIES, AND POWER-LINE CONDITIONER] * INSTRUMENTS, SUCH AS FOOT PEDALS FOR USE WITH ELECTRONIC MUSICAL INSTRUMENTS *