LPF-8 signal conditioner combines an 8-pole low pass Bessel filter with a DC amplifier. Applications include signal conditioning in electrophysiological, cellular and neurological sciences. Unit features include digital frequency readout, visual input offset, clipping indicator and gain telegraph outputs. A circuit that uses no mechanical switching insures reliability. Cut-off frequency is dialed up using a single rotary control in two ranges. The full frequency range spans 0.1 Hz to 20 kHz in a resolution of 0.1 Hz or 10 Hz, depending on the range selected. The bypass switch selects full amplifier bandwidth for comparison of filtered and unfiltered signal.