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This audio filter was found in the August 1993 issue of Radio Electronics magazine. It cuts low and high frequencies corresponding to rumble and scratch noises that occur on turntables.
This circuit is from an English magazine of 1977. The circuit is still current, just using BC547...
This circuit was obtained in an old Elektor. It is a reference, since the integrated products of the...
This circuit was found in a European technical documentation from 1991. It is a circuit that must...