Sound Semiconductor let us know that they’ve introduced a next-generation Bucket Brigade Delay (BBD) integrated circuit, the SSI2100, that they say is “the first new BBD development in decades”.

A BBD IC is an analog chip that creates a delay effect using a series of capacitors and transistors. It works like a fire brigade passing buckets, with each capacitor (bucket) holding a portion of the audio signal and passing it to the next one in line, when triggered by a clock pulse. BBDs were used in ’70s and ’80s delay effects, prior to the introduction of digital delay effects.

The SSI2100 is a 512-Stage BBD that offers a wide range of delay times, using clock frequencies from 1kHz to over 2MHz. Special care was taken to faithfully reproduce the bucket brigade chain to preserve “mojo” of vintage analog delay circuits.

“Before we could even start development in earnest of the SSI2100, we had to fully understand how these unusual devices work,” stated Neil Johnson, designer of the SSI2100. “From there it became a very fun project to complete.”

Sound Semiconductor says that they took advantage of a modern CMOS IC process that not only permits reduced chip die size, but also allows the addition of new features.

The SSI2100 includes an on-chip clock driver with anti-phase outputs that accepts a single TTL/CMOS 5V or 3.3V input that can be easily generated from a wide range of sources, negating the need for a traditional companion clock generator IC. In addition, the SSI2100 incorporates a clock tree to distribute the two anti-phase clocks throughout the chain for improved fidelity.

The SSI2100 also internally provides the legacy “14/15 VGG“ supply voltage, needing only an external capacitor.

A novel circuit (patent pending) provides noiseless gain, allowing easy connection of multiple SSI2100’s for longer delay times, without having to recalibrate inputs and outputs. An additional benefit to daisy-chaining is access to intermediate feedback taps, for interesting reverb and other psychoacoustic effects.

Pricing and Availability:

The SSI2100 is available now in a compact SOP-8 package, and is believed to be the first BBD IC to be offered in a surface mount package. Pricing is $1.08 at 1k pieces, with samples available to qualified OEM’s.