passive audio notch filter

built this to see what it was like. found it in craig anderton's book 'electronic projects for musicians.' it's a passive notch filter using an inductor and capacitors. cuts out selected frequencies from an audio signal. the knob on the right is a rotary switch that selects the frequencies to be filtered out, the knob on the left controls the depth of the filtering effect.

the rotary switch has six positions: far left position bypasses the filter circuit, other positions select different value capacitors. the toggle switch in the middle changes the value of the inductor. so you get at total of 10 different filter frequencies.

passive = requires no power source, but there is a drop in volume.

Category:

Music

Tags:

• craig
• anderton
• passive
• filter

[lacolumnadurruti]

@nomadictv i just looked up the varitone and the schematic is a little different, but the basic concept is the same.

[nomadictv]

nice! is it different from a varitone circuit or just the same?