PSP BBDelay

PSP’s latest delay models a classic bucket‑brigade device, and can go from slightly dusty repeats to sonic swamp!

Coming after the older tape‑loop and magnetic‑drum echo devices, bucket‑brigade device (BBD) delays were the first really affordable delay units. Their unique character results from a curious digital‑like (but all‑analogue) technology: the delay is created by passing an electrical charge along a chain of cells, rather like passing water along a chain of buckets to douse a fire. The input is measured as a series of samples, just like with a digital system, but the samples are stored as analogue voltages.

As with digital systems, to avoid aliasing the clock rate must be at least twice that of the highest frequency being handled, and filters are required at the output to reconstruct the stepped analogue signal coming out of the BBD chain. (Some of the earlier BBDs pushed the delay time by dropping the clock frequency so far that there was audible aliasing.) Other characteristics of BBDs are that, as the chain of cells gets longer or clock rate is dropped, the repeats lose high end and become more distorted. The problem of noise was often tackled using compander circuits, which of course introduced side‑effects of their own.

New Kid On The BBlock

PSP’s new BBDelay plug‑in was inspired by the Dynacord VRS 23 BBD delay/reverb, but it’s not a direct emulation and PSP have added a number of thoughtful features. It supports all the mainstream plug‑in formats for macOS and Windows and is authorised using an iLok account. In its standard mode, it can produce mono or dual‑mono delays of up to 1600ms, though this can be increased to 3200ms by switching to x2 mode and setting Delay (the clock rate) to its minimum 0.25 setting (the maximum being 4). PSP modelled various components, including the individual BBD chips and compander circuit. However, companders in old BBD systems were never perfectly aligned — a major source of misalignment was the signal that’s compressed before entering the delay being very different from that which emerges — and that flaw is modelled here, too.

There are lots of controls, and PSP have organised them in a number of sections on a single GUI — the right decision, I think, as it fits well on most screens today, and you never have to search through tabs or menus to find the right control. There’s a level meter on the left, and a row of stars to the right of the preset window allows eight favourite presets to be called up directly.

Turn Regen right up and the delays build up into a dub‑like wall of sound, but it never gets too loud.

Most of the main controls in the centre panel are intuitive, but because it adjusts the clock speed you turn Delay (time) anticlockwise for longer delays. A red, numeric LED‑style display shows the delay time in milliseconds, and a row of buttons below accesses x2 mode, Time Base and Effect Mode. Time can be adjusted smoothly, with authentic pitch changes during...