The Shaver Mystery

Two BBD-based flanger circuits: one set by a knob (FLANGE1), the other voltage controlled (FLANGE2, FINE2 and CV2, or just set by its knobs). The intention is a thru-zero effect as the voltage-controlled flanger shifts to longer, the same or shorter delays than the fixed one. The design is partly based on Paul Williams' Infinite Flanger (Home & Studio Recording, September 1985). MIX sets the ratio of input signal and fixed flanged signal fed to the output, and the ANTI PHASE switch feeds it to the inverting or the non-inverting input of the output op amp; with F/BACK, these give a great variety of effects and sounds. The LED shows the clock activity of the two VCOs driving the BBDs (a red/green LED turns yellow when their frequencies are close). Two SSI2100 512-stage BBDs, clocked between 30 kHz and 500 kHz by two LTC6990 VCOs, anti-aliasing filters at 15 kHz and an SA571 compandor against clock noise. The two outputs are the same.

Key features

• IN1, IN2 and CV2 in; two OUT, the same signal
• FLANGE1, FLANGE2, MIX, FINE2, F/BACK, CV2 and IN1 knobs
• An ANTI PHASE switch; an LED showing the two VCOs' clocks
• 8 HP; Nonlinearcircuits publishes no current draw, depth or assembled price (it sells the DIY PCB and panel), and ModularGrid lists none