Tiptop Audio - 277t Signal Delay Unit

The 277t is a rather unusual kind of delay module. Its origins go back to an unfinished Buchla design from 1972, when digital audio delay was still very new territory and tape was the established way of making echoes. Don Buchla’s idea was a clocked digital delay line with four separate taps at ¼, ½, ¾ and the full delay time — less a ready-made echo effect than a collection of building blocks for constructing one. Tiptop Audio have taken the surviving schematic as the starting point for the 277t, bringing an idea that never became a finished Buchla module into the Eurorack 200t series.

The building-block approach really feels like what defines the 277t in use. There is no dedicated feedback knob, wet/dry control or neatly prescribed signal path. Instead, three attenuated inputs feed the delay and the four taps appear independently at the outputs. Patch one of those outputs back into another input and you have feedback; choose a different tap and its timing changes. Put a filter, frequency shifter, LPG or something considerably less sensible in that return path and the repeats can be processed before they come around again.

Delay time itself is voltage controllable, with a bipolar attenuverter, and there is a separate modulation input intended for audio-rate FM of the delay clock. Changing that clock does more than alter the spacing between repeats — it can also bend the pitch of the delayed signal, opening the door to chorus-like movement, unstable warbles and more abrupt pitch shifts. There is also a choice between the original short delay range and a longer setting. It is perhaps best understood as a patchable time-domain module rather than a classic delay : you supply the routing, and the 277t supplies four places in time to work with. Definitely not your usual delay module, but that is precisely what makes the 277t such an interesting one to patch with.

Features:

• Based on Don Buchla’s unfinished 1972 Model 277 Signal Delay Unit
• Clocked digital delay-line design
• Four simultaneous delay-tap outputs: ¼, ½, ¾ and full delay time
• Three audio inputs with individual attenuators
• Three-channel input mixer
• Main Rate control for delay time
• CV control of delay time with bipolar attenuverter
• Separate audio input with attenuator for FM of the delay
• Switchable original short and extended delay-time ranges
• Feedback created by patching delay taps back into the inputs
• Overload indicator LED