Simple Rumble Filter
#active filter
#high pass filter
#LM387
#audio processing
#cutoff frequency
#12-dB per octave
#rumble filter
#signal conditioning
Description: This circuit is a two-section active high-pass filter using an LM387, with a cutoff frequency below 50 Hz at a slope of 12 dB per octave. It will help reduce rumble caused by turntable defects in record systems.
The two-section active high-pass filter designed using the LM387 operational amplifier is intended to eliminate low-frequency noise, particularly rumble, which can arise from mechanical imperfections in turntables. The cutoff frequency is set below 50 Hz, ensuring that frequencies below this threshold are attenuated effectively, while allowing higher frequencies to pass through with minimal loss.
The circuit employs two cascaded stages of active filtering, which enhances the overall performance by achieving a steeper roll-off of 12 dB per octave. In practical terms, this means that for every doubling of frequency beyond the cutoff, the output signal level decreases by 12 dB. This characteristic is particularly beneficial in audio applications, where maintaining the integrity of the desired audio signal while suppressing unwanted low-frequency noise is crucial.
The LM387, a versatile operational amplifier, provides the necessary gain and bandwidth for the filter stages. It is configured in a non-inverting setup to ensure stability and low distortion in the output signal. The design incorporates feedback resistors and capacitors that define the filter's frequency response. Careful selection of these components is essential to achieve the desired cutoff frequency and filter characteristics.
Additionally, the circuit may include power supply bypass capacitors to enhance stability and reduce noise from the power supply, which can otherwise affect the performance of the filter. The layout of the circuit should minimize parasitic capacitance and inductance, which could alter the filter's response and degrade audio quality.
Overall, this active high-pass filter design is a valuable tool in audio systems, particularly for vinyl playback, where it addresses common issues related to low-frequency rumble, thereby improving the overall listening experience. This circuit is a two-section active HP filter using an LM387, with a cutoff below 50 Hz at 12-dB per octave. It will help reduce rumble as a result of turntable defects in record systems.
The two-section active high-pass filter designed using the LM387 operational amplifier is intended to eliminate low-frequency noise, particularly rumble, which can arise from mechanical imperfections in turntables. The cutoff frequency is set below 50 Hz, ensuring that frequencies below this threshold are attenuated effectively, while allowing higher frequencies to pass through with minimal loss.
The circuit employs two cascaded stages of active filtering, which enhances the overall performance by achieving a steeper roll-off of 12 dB per octave. In practical terms, this means that for every doubling of frequency beyond the cutoff, the output signal level decreases by 12 dB. This characteristic is particularly beneficial in audio applications, where maintaining the integrity of the desired audio signal while suppressing unwanted low-frequency noise is crucial.
The LM387, a versatile operational amplifier, provides the necessary gain and bandwidth for the filter stages. It is configured in a non-inverting setup to ensure stability and low distortion in the output signal. The design incorporates feedback resistors and capacitors that define the filter's frequency response. Careful selection of these components is essential to achieve the desired cutoff frequency and filter characteristics.
Additionally, the circuit may include power supply bypass capacitors to enhance stability and reduce noise from the power supply, which can otherwise affect the performance of the filter. The layout of the circuit should minimize parasitic capacitance and inductance, which could alter the filter's response and degrade audio quality.
Overall, this active high-pass filter design is a valuable tool in audio systems, particularly for vinyl playback, where it addresses common issues related to low-frequency rumble, thereby improving the overall listening experience. This circuit is a two-section active HP filter using an LM387, with a cutoff below 50 Hz at 12-dB per octave. It will help reduce rumble as a result of turntable defects in record systems.
Digitally tuned low power active filter
This constant gain, constant Q, variable frequency filter provides simultaneous low-pass, bandpass, and high-pass outputs. With the specified component values, the center frequency will be 235 Hz for high logic inputs and 23.5 Hz for low logic inputs. The quality...
Averager and Peak Hold/Extender Signal Conditioner
A signal averager circuit can be formed by an amplifier and active signal rectifier, which is implemented using two operational amplifiers in this circuit.
The signal averager circuit utilizes two operational amplifiers (op-amps) to achieve signal averaging through amplification and rectification....
Five-pole active filter
The realization of a type 03 receive filter is achieved using eight OP-08 operational amplifiers. The response curve indicates that the requirement for greater than 30 dB attenuation in the stop band has been satisfied. Furthermore, the noise performance has...
Signal Conditioning Circuit for KMI 15/x Rotation Speed Sensor
A modulated current is supplied by the integrated rotational speed sensor KMI 15/x. This current signal needs to be converted into a ground-referenced voltage signal.
The KMI 15/x sensor operates by generating a modulated current proportional to the rotational speed of...
Active Filter Design with OpAmps
This application note aims to introduce filter designers to the basics of active filter design using monolithic integrated circuit operational amplifiers (op-amps). It includes a table of transfer functions and network equations for high-pass, low-pass, band-pass, and band-reject filters. Several...
lm387 dynamic microphone preamplifier
A dynamic microphone preamplifier can be constructed using the LM387 dual operational amplifier integrated circuit. The input impedance is approximately 47k ohms, primarily determined by resistor R1. If a dynamic microphone with a different impedance is to be connected, resistor...
Audio Beat Detect ?« Electronic Product Design
This circuit employs a digital potentiometer to enable the microcontroller to automatically adjust the circuit's gain according to the ambient audio volume. However, a standard potentiometer can be used if automatic adjustment is unnecessary. The low-pass filter design is based...
Single Supply Active Filter with Virtual Ground
All filter stages utilizing a Virtual Ground will exhibit the Virtual Ground DC potential at their outputs, whereas all stages employing a resistive divider at their input (without a Virtual Ground) will present the divider potential at their output. For...
Three amplifier active filter
The active filter is a state variable filter with bandpass, high-pass, and low-pass outputs. It is a classical analog computer method of implementing a filter using three amplifiers and only two capacitors.
The state variable filter is a versatile circuit design...