Skip to main content


Audio Noise Filter and Bandpass Filter for Audio Frequency Band

Audio Noise Filter and Bandpass Filter for Audio Frequency BandThis audio noise filter circuit is a bandpass filter for audio frequency band. It filters unwanted signals that are lower or higher than the audio frequencies. It has 2 filters: a low pass filter and a high pass filter in a cascade configuration. Both filters are second-order filters with a 24 dB/octave fiter capability. The 3 dB cut-off freq. are 11.8 Hz and 10.7 kHz.

The bandpass characteristic can be changed by changing the values of the capacitors and resistors. If you want to raise the bottom cut-off freq., you must reduce the values of C1 up to C4. For lowering the bottom cut-off freq. you must increase the values. If you want to reduce the top cut-off f you must raise the values of R5 up to R8 and decrease it in order to increase the top cut-off frequency.
Noise Filter circuit diagram

Audio Noise Filter Parts List R1 = R2 = 56kΩ
R3 = 39kΩ
R4 = 100kΩ
R5 = R6 = R7 = R8 = 3.3kΩ
C1 = C2 = C3 = C4 = 0.33µF ceramic
C5 = C6…

TDA7294 150 W Power Amplifier

TDA Amplifier Circuit stereo 150W

The TDA8950 is a high-efficiency Class D audio power amplifier. The typical output power is 2 × 150 W with a speaker load impedance of 4 Ω. The TDA8950 is available in both HSOP24 and DBS23P power packages. The amplifier operates over a wide supply voltage range from ±12.5 V to ±40 V and features low quiescent current consumption. The TDA8950 is a two-channel audio power amplifier that uses Class D technology. For each channel, the audio input signal is converted into a digital PWM signal using an analog input stage and a PWM modulator. To drive the output power transistors, the digital PWM signal is fed to a control and handshake block and to highand low-side driver circuits. This level-shifts the low-power digital PWM signal from a logic level to a high-power PWM signal switching between the main supply lines. A 2nd-order low-pass filter converts the PWM signal to an analog audio signal that can be used to drive a loudspeaker.

150 watt amplifier cir…

Car subwoofer filter circuit

Circuit description:
Here is the circuit diagram of a simple subwoofer filter that can be operated from a 12V DC supply. Such a circuit is very useful in automobile subwoofer applications. The circuit is nothing but a low pass filter whose pass frequency can be adjusted between 60 to 160 Hz. The circuit is designed around the TL072 dual BIFET opamp IC. Out of the two opamps inside the chip, IC1A is wired as a buffer. The left and right audio inputs after mixing is fed to the input of the IC1A using the DPDT switch S1. Switch S1 is the phase control switch which can be used to make the subwoofer in phase with other speakers. When S1 is in position 2, 180 degree phase shift will be induced.POT R7 can be used for controlling the level. IC1B forms the low pass filter whose pass frequency can be controlled by adjusting the dual gang POT R13.
Circuit Features: The circuit can be powered from 12V DC.IC1 must be mounted on a holder.S1 is a DPDT switch.R13 should be a dual gang linear POT.C5 and…

22 Watt Car Subwoofer Amplifier

Circuit Description
     The stereo signals coming from the line outputs of the car radio amplifier are mixed at the input and, after the Level Control, the signal enters the buffer IC1A and can be phase reversed by means of SW1. This control can be useful to allow the subwoofer to be in phase with the loudspeakers of the existing car radio. Then, a 12dB/octave variable frequency Low Pass filter built around IC1B, Q1 and related components follows, allowing to adjust precisely the low pass frequency from 70 to 150Hz. Q2, R17 and C9 form a simple dc voltage stabilizer for the input and filter circuitry, useful to avoid positive rail interaction from the power amplifier to low level sections.      This unit is intended to be connected to an existing car stereo amplifier, adding the often required extra "punch" to the music by driving a subwoofer. As very low frequencies are omnidirectional, a single amplifier is necessary to drive this dedicated loudspeaker. The power amplifie…

200W Audio Amplifier Circuit

Circuit description:
Connecting two TDA2030 thru cheap power transistors we can create a amplifier wich can deliver a higher power. With the components value from the schematic the total amplifier gain is 32 dB. The speaker can be 2 ohm instead of 4 ohm if we use the TIP transistors. TDA 2030 is produced by SGS Ates and is a complete audio amplifier. AB class of the final amplifier cand deliver up to 14W on 4 ohm at a +-14V power supply. With a proper designed power supply this audio amplifier can output 200W.
Circuit diagram:

Part list IC1, Ic2 TDA 2030T1, T3 = BD 250, TIP 36T2,T4 = BD 249, TIP 35D1 … D4 = 1N4001
150 watt audio amplifier circuit
400w amplifier circuit diagram
200w stereo digital audio power amplifier
3055 transistor audio amplifier circuit
1000 watts amplifier circuit diagram
200 watt audio amplifier circuit diagram
4 transistor audio amplifier
transistor audio amplifier circuit diagram

Subwoofer Circuit Diagram

Circuit Descrition The acoustic spectrum is extended by very low frequencies 20Iz and reaches as the 20000Iz in high frequencies. In the low frequencies is degraded the sense of direction. This reason us leads to the utilization speaker for the attribution of very low frequencies. The manufacture that to you we propose distinguishes these frequencies, in order to him we lead to the corresponding amplifier. The acoustic filters are met in various points in the sound systems. The knownest application they are the filters baxandal for regulating tone low and high frequencies and filters crossover where the acoustic region is separated in subareas, in order to it leads the corresponding loudspeakers. The application that to you we propose is a simple filter of region that limits the acoustic region (20-20000Hz) in the region 20-100Hz.
With the manufacture that to you we propose you can make a active filter in order to you lead a loudspeaker of very low frequencies. With this you will plac…

100W MOSFET power amplifier

Circuit Description: MOSFET power amplifier circuit based on IRFP240 and IRFP9240 MOSFETs is shown here. The amplifier operates from a +45/-45 V DC dual supply and can deliver 100 watt rms into an 8 ohm speaker and 160 watt rms into a 4 ohm speaker. This Hi-Fi amplifier circuit is suitable for a lot applications like general purpose amplifier, guitar amplifier, keyboard amplifier. The amplifier can be also used as a sub woofer amplifier but a subwoofer filter stage has to be added before the input stage. The amplifier has a low distortion of 0.1%, a damping factor greater than 200, input sensitivity of 1.2V and the bandwidth is from 4Hz to 4 KHz.
Circuit Features: Assemble the circuit on a good quality PCB.Use a +45/-45 V DC, 3A dual supply for powering the circuit.Power supply voltage must not exceed +55/-55 V DC.Before connecting the speaker, check the zero signal output voltage of the amplifier and in any case it should not be higher than 50mV. If it is higher than 50mV, check the ci…