Princeton Delay

audio delay

The Princeton 1U Tile is an audio delay module using the PT2399 Echo Processor IC. The Tile was designed to be a building block for constructing time based effect patches. There are controls for “INPUT” level, “FEEDBACK” amount and delay “TIME”. However, there is not a control for the wet/dry mix since this would be impractical in complex patches using several delay elements. Instead the mix control can be constructed from other Tiles like the X-Fade or Mix-A.

The PT2399 is a simple echo processor chip that was originally designed to provide a low cost reverb effect in Karaoke machines. This crude low performance chip can be exploited to add interesting sonic artifacts when operated outside of its intended range. To exploit the broken edge of this chip the Princeton Tile uses a 20-turn Range pot to set the maximum delay time for the module. When the Range pot is cranked to the full counterclockwise position the “TIME” slider can be set for short delays of the length that the chip was designed to produce (approximately 30mS to 300mS although each unit is a little different). Interesting things can happen when the chip is pushed to produce longer delay times by cranking the Range control clockwise. Nearing the full clockwise position the delay times can be several seconds long where the audio will eventually disintegrate into an unrecognizable replica of the original sound. These long (broken) delay times can produce interesting rhythms when looped by adding feedback. The “FEEDBACK” control is capable of providing infinite repeats when set near the top of its range. When set too high the regeneration can overload the input and distort but this can add interesting textures into the delay line and can be manually manipulated to the desired amount. To prevent new audio from entering the delay line the “INPUT” slider can be turned off.

The CV input allows the delay time to be modulated using control voltage. The range on this input works in conjunction with the “TIME” slider to set the delay time. The CV input supports bipolar input signals so that negative input voltages will reduce the delay time and positive voltages will increase it. For subtle time based effects the CV input will need to be attenuated to avoid extreme delay time swings.

The Princeton Delay 1U Tile is nothing like the pristine digital delays available today. It can be clumsy and unpredictable and there will be variations between units, however these technical defects offer a delay building block with unique sonic tonalities and is ripe for experimentation.

https://pulplogic.com/product/princeton/