Pittsburgh Modular - Cascading Delay Network
A study in complexity through simplicity. The Cascading Delay Network combines four 750ms voltage controllable delays with a labyrinth of internal analog signal routing to create a tangle of unique time based effects. Five distinct Cascade Modes internally reconfigure the delay lines and feedback paths with the press of a button creating long unified repeats, dense sonic clouds, multi-tap delays, or multiple effects at once.
This page is also the manual and is going to get nerdy and probably confusing very quickly. Before you dig in, know that understanding exactly how everything in the Cascading Delay Network works is not necessary to get musical and interesting results. As always, patch with your ears.
Digital, but barely.
The Cascading Delay Network houses four individual delay channels based on the Princeton Technologies digital PT2399 karaoke echo processor from the 1990’s. A 1 bit digital delay chip with 44K bit memory that works in a similar way to the older, and much loved analog BBD chips. The unique sound and quirks of the PT2399 make it the perfect choice for an over the top low-fi delay dripping with character.
Each channel of the Cascading Delay Network has a dedicated set of controls allowing it to function as an independent delay. Input jack, input level, delay time, repeats, dual delay time CV attenuators, wet-dry mix, and an output jack. Four straightforward, 750ms delays at your disposal. See, that was simple.
The 4 delay channels can be merged or chained together in a myriad of different ways called Cascade Modes. Each Cascade Mode offers a few different feedback options. Pressing the Cascade Mode button cycles through all the available modes. The simple interface makes stereo delays, long delays, multi-tap delays, chained delays, echo clouds, complex feedback paths, and other more complex signal paths easy.
Basics, but important.
Inputs are normaled together. Input 1 is normaled to input 2. Input 2 is normaled to Input 3 and Input 3 is normaled to input 4. That means if you patch into input 1, the signal passes to all for delay channel inputs or if you patch into channel 3, the input signal also passes to channel 4. Depending on the selected Cascade mode, this creates parallel or multi-tap delays.
The output you use is important. The “correct” output to use for each Cascade mode is the output of the last delay channel used. For example if you are using Cascading Mode 2 to group channels 1 through 3 into a single delay, the “correct” output to use would be the channel 3 output because it is the output of the last active channel. The “correct” output for each mode is noted in the Cascade Mode descriptions. “Correct” is used in quotes because all the outputs are always active. Patching into an output before the last delay channel can yield interesting results.
The Repeats Slider may not be active. If the Repeats Slider LED is off, the slider is not active. Repeats Sliders are enabled and disabled based on the active Cascade Mode. For example, in Cascade Mode 1A only the Channel 1 Repeats Slider is active because all 4 channels are grouped together as one delay with a single feedback line..
Input Level knob position is important. As expected, Input Level knobs set the incoming signal level for each channel. Maybe less expected is that all the Input Level knobs are active all the time. Even if the channel is not the first channel of a delay group. Turning up the Input Level Knob for grouped channels adds multi-taps to the delay. The exact time the multi-tap is added to the delay path is determined by the sum of the previous delay channels in the group. As an example, if the Cascading Delay Network is set to Cascading Mode 1 so all 4 channels are grouped together as a single delay, turning up the Input Level knob on channel 3 will add a multi-tap into the signal path after the signal passes through channel 1 and channel 2. If you think about this too much it creates a time travel paradox where an audio signal meets an older version of itself within the delay chain and may create a hole in the space-time continuum. Tread lightly.
The Wet / Dry Output Mix knob may not be active. Only the Wet / Dry Output Mix knob for the channel used as an output matters. The signal paths between channels do not pass through the Wet / Dry Output Mix knobs. The exception to this rule is if the Mix Output Section outputs are used. If so, the Wet / Dry Output Mix knobs for the appropriate channels will be active. That leads us to…
Mix Outputs are interesting. The mix outputs are designed to create awkward groupings of channels, perfect for more interesting and complex delay effects. Results vary based on the selected Cascade Mode.
The Modulation Router is very simple. There are 2 CV inputs (A and B). Each CV input can affect the delay time of all 4 delay channels using the 4 rows of CV attenuators. CV A input is inverted and normaled to the CV B input. That means if you patch a modulation source into CV A, CV B receives an inverted version. Patching directly into CV B does not invert the modulation signal.