Signal Delay Unit

The 277 Signal Delay Unit was invented in 1972 and was one of the first digital delay lines ever made. A delay line passes audio through a series of clocked shift registers, with the clock speed determining the delay time. On its own, this simply delays the audio, but routing signals through different paths opens up further possibilities. For example, feeding the output back into the input creates repeating echoes, while placing additional processors in the feedback path allows for more complex effects. Modulating the clock speed can also create pitch-shifting effects. As such, the 277t should be considered, among its other functions, a centerpiece for building effects by patching it with other modules, rather than a modern delay effect module, which typically features a preconfigured signal path.