ABSTRACT

There are two ways to control the delay time: either changing the distance between the record and replay head or changing the tape speed. Moving any head is a mechanical challenge, and it is much easier to change the tape speed. There is a limitation, however, to how slowly the tape can travel, so some units employ a number of replay heads at different distances, and the rough selection of delay time is made by selecting which head feeds the output. The tape speed is then used for fine adjustments.