An early design for an echo or delay effect where the input audio would be sampled as an analog voltage, and held for a brief moment. Then at the next above-audio sample rate clock pulse, this voltage would get passed to the next sample and hold (bucket) in the circuit, while a new level was sampled. Bucket brigade delays (BBDs) usually have numbers of stages or buckets that are powers of two (256, 512, 1024, 2048, etc.); the delay length is determined by the number of stages multiplied by the time interval between samples.
BBD effects tend to have two characteristics: they are not the most pristine sound-quality-wise (noise is the biggest complaint), and if the sample rate goes into the audible range (below 20 kHz), the clock frequency can be heard as a whine superimposed on top of the audio being processed – unless the design has a filter that is set up to remove that clock rate, or if you do it yourself using a filter or EQ (equalization) module. Plus their cost goes up with the number of stages. As a result, BBDs are often reserved for chorus units, or purposely dirty echo units.« Back to Glossary Index