DO-IN SFL-1 STEREO FLANGER

In the early 60's, the flanging effect was produced by slowing down the playback of a recorded track by dragging a finger against the tape-reel "flange" to delay the signal. When this altered track was played back against the original the resulting peaks and notches in the frequency spectrum produced the signature "swoosh" we now know so well. Later the effect was duplicated using analog BBD (Bucket-Brigade Delay-line) IC. However, not too much of pedals can capture the sound of those old tape reels being slowed down and speeded up.