High Pass Filter Circuit | Rumble Filter

An electric filter or simply a filter is an electric network which passes or allows without loss, transmission of electric signal within certain frequency range but stops or disallows transmission of electric signal outside this frequency range.

The three most-popular filter found in audio equipment are the High Pass Filter (rumble filter), Low pass filter (scratch filter) and speech filters. The rumble filter is a high-pass filter, used to suppress the low-frequency rumbling sound associated with old and worn-out turntable and tape deck mechanisms. Here we explain you how high pass filter or rumble filter work with circuit diagram and description.

We also define high pass filter or rumble filter circuit as it passes all frequency above a specified frequency, called the cutoff frequency fc and rejects all frequency below fc.

Circuit description of High pass filter or Rumble filter using LM387

The circuit of high pass filter is build around general purpose op-amp IC LM387. Input from amplifier is given to the inverting input pin 2 and pin 7 through coupling capacitor C1 and C3. Unwanted frequency is filter by capacitor C4. Where capacitor C2 is used as feedback capacitor connected from output to input. Output is taken from pin 4 and pin 5 through capacitor C7. Non-inverting pin 1 and 8 is connected to ground through capacitor  C5.

high pass filter or rumble filter using LM387

F0 = 60Hz,

Butter worth Q = 0.707

A0 = 1

SLOPE = -12dB (OCTAVE)

The working of the circuit high pass filter using LM348/LM741 is same as circuit 1 (High pass rumble filter using LM387). Capacitor C4 is only connected when IC lM348 is used not while using LM741.

high pass filter or rumble filter using LM741 or LM348

PARTS LIST OF HIGH PASS FILTER USING LM387 (CIRCUIT 1)

Resistor (all ¼-watt, ± 5% Carbon)
R1 = 220 KΩ

R2 = 1 MΩ

R3 = 180 KΩ

Capacitors
C1 – C3 = 5.6 kPF

C4 = 0.033 µF

C5, C6 = 0.1 µF

C7 = 10 µF/12V

Semiconductors
IC1 = LM387

PARTS LIST OF HIGH PASS FILTER USING LM741/LM348 (CIRCUIT 2)

Resistor (all ¼-watt, ± 5% Carbon)
R1 = 220 KΩ

R2 = 1 MΩ

Capacitors
C1 – C3 = 5.6 kPF

C4 = 0.047 µF

C5, C6 = 0.1 µF

Semiconductors
IC1 = LM348/LM741
  • Good explanation of the high pass filter and everything you can do with it. Thanks so much for the great information.