The Black BBD from Erica Synths is a BBD-based analog echo with a great retro sound. The module has two parallel delay lines, (1024 and 4096 stages), which are continuously mixable. This way clear echoes in short or long, as well as interesting combinations in between can be realized. The switch Colour allows the compromise between a wider frequency band and optimized clocknoise, which is very typical and charismatic for this effect genre. If the delay time is modulated with the internal LFO, which has triangle and square waveforms, low times create nice chorus and vibrato effects like you might remember from old studio equipment of the late 70s. With longer, modulated delay times, wacky delay effects with pitch shifting are possible. The mix control can also be modulated with a control voltage, which makes the effect selectively applicable.