The scenario
A line-level audio signal passes through an input resistor to a common bus, where five series RLC branches to ground create adjustable resonance notches at 60 Hz, 250 Hz, 1 kHz, 3.5 kHz, and 12 kHz; the equalized signal is AC-coupled to a 100k load.
What is in this drawing
Read the decisions behind it.
01
Selected passive shunt topology rather than active op-amp filters
02
Used series R-L-C branches with fixed resistors to set notch depth per band
03
Added input series resistor and AC output coupling/load for realistic integration
Reuse for passive line-level tone shaping where no active gain is required, especially in tube preamp/amplifier front-ends.
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