Biphaser

EE 46 March 1987 There are various ways of ob- taining the well-known phasing or flanging sound effect. Most phasers use phase-shifting net- works, bucket brigade delay lines, selectively activated L-C networks, comb-type filters, or the like. The present circuit utilizes phase shifting, but has none of the drawbacks gener- ally associated with this type of phaser, since provision has been made to obviate the troublesome amplitude-modu- lation effect caused by selec- tive filtering at relatively low phaser speed settings. Where this effect is still tolerable-and often expressly sought after- with the rhythm guitar, it all but ruins the sound of numerous solo instruments, whose par- ticular sound is not in any way embellished by appreciable volume variations. The use of a phaser based on the periodic shifting of, say, two stop-band filters results in a very lively ef- fect with input signals relatively rich in harmonics, e.g. those of an acoustic rhythm guitar. The same phaser,...