This project is an audio amplifier based on TDA2050 and LM1875.
This is not an ordinary project, but an attempt to make a PCB that is suitable for TDA2050 and LM1875 and has all the necessary circuitry on board – power supply, speaker protection, delayed turn-on and fast turn-off. This is achieved using the convenient uPC1237 IC.
TDA2050 and LM1875 are pin to pin compatible, the differences in their schematics are the values of a couple resistors and one capacitor. All this allows to make an universal circuit board, suitable for any of these two ICs.
Audio Power Amplifier with TDA2050 - [Link]
3 Tone Siren project produces Gun Sound, Police Siren and Ambulance Siren effects from a speaker. This project is built around UM3561 IC driving an LM386 audio amplifier to give that extra punch.
3 Tone Siren - [Link]
by MrLeeh @ instructables.com:
I wanted to have my personal, nice looking Mediabox with a big display and remote control. I’ ve been playing around with the Raspberry for a while so I decided this would be the platform of choice for this project. I’ m actually a fan of Steampunk so I decided to use a Steampunkish style for the box.
Raspberry Mediabox Steampunk style - [Link]
Infrared headphones can be used for listening to music or television cordlessly. The headphones utilize a transmitter that connects with audio cables to the audio source, such as a home entertainment center. The transmitter utilizes light-emitting diodes (LEDs) to direct a focused beam of invisible pulsating light towards a receiver built into the headphone set. The pulsations act as ON/OFF signals that are translated digitally by the receiver into audible sound waves. Most infrared headphones have an effective range of about 30 feet (~10 meters) or less, and require a clear line of sight between transmitter and receiver.
The headphones pick up the light with a receiver and turn it back into sound. The receiver has an infrared CDS cell, which produces a pulse of electricity every time infrared light lands on it. The cell is designed to pick up the particular frequency of light produced by the transmitter, so it is not disturbed or thrown off by other light. A small computer inside of the receiver takes these pulses of electricity and turns them into an audio signal. This audio signal is then amplified and sent to the headphones themselves, which play the sound.
For the receiver side, a photodiode D1 feeds high gain IR remote control preamp IC, a CA3237E. U2 is a PLL FM detector tuned to around 100 kHz. The detector output is amplified by U3 and it can drive a speaker or a set of headphones.
Wireless IR Headphone Receiver - [Link]
5W Stereo Audio Amplifier project based on BA5406 IC which is suitable for application like stereo radio cassette player, stereo components systems etc.
The Heart of the project, BA5406 is a dual OTL monolithic power IC with two built-in, high output speaker amplifier circuits. High output of 5W×2 can be produced when VCC=12 V and RL=3Ω, and 2.8 W×2 when VCC=9V and RL=3Ω. The BA5406, which uses a high allowable power dissipation package, has a simple heat-sink design.
5W Stereo Audio Amplifier - [Link]
Focus a beam of sound at objects or into your head!
The Soundlazer directional audio project is the continuation of my first and very successful project here on Kickstarter. I developed the Soundlazer “Snap” during my quest to lower the cost of this amazing technology and give backers the opportunity to explore new possibilities in directional audio.
Parametric speakers like the Soundlazer are directional speaker systems. They use ultrasonic carrier waves to transmit audio to listeners in a focused beam of sound that acts like light from a laser. Generally speaking, only the person standing in front of a parametric speaker can hear the audio being transmitted. People to the sides of the directional audio source hear little or no sound.
Soundlazer “Snap” – The Directional Parametric Speaker - [Link]
This project is designed to operate with minimum of external components. This amplifier offers high quality and high performance audio at very low distortion. Project is based on nationals LM1875 IC. The IC is thermal and short circuit protected.
The LM1875 is a monolithic power amplifier offering very low distortion and high quality performance for consumer audio applications, the project work on single supply. Device overload protection consists of both internal current limit and thermal shutdown.
20W Audio Amplifier - [Link]
A project has been designed around Holteks Ht8970 voice echo IC. Project can be used in various audio systems karaoke, toys, animatronics, show, display, exhibitions, and sound equipments.
The HT8970 is an echo/surround effect processor. It is designed for various audio systems including karaoke, television, sound equipments, etc. The chip consists of a built-in pre-amplifier, VCO or Voltage Control OSC, 20Kb SRAM, A/D and D/A converters as well as delay time control logic.
Voice Echo - [Link]
We are building another enjoyable weekend DIY project. This is an audio power amplifier based on LM1876 which can deliver up to 20W per channel into 4 or 8 ohm load and guarantees less than 0.1% THD + N (Total Harmonic Distortion + Noise).
The amplifier is powered by -15 0 15 VAC symmetrical supply. The full bridge diode rectifier and the smoothing capacitors convert the AC input to ±21 VDC which is used to power LM1876. The inductors on the AC input line reduces the noise arising from the mains line.
DIY LM1876 Dual 20W Audio Power Amplifier - [Link]
This article introduces high quality digitally controlled 2.1 channel analog audio power amplifier system. This project is mainly based on TDA7377 AF power amplifier and PIC18F452 8bit microcontroller. Basic technical features of this receiver are covered in table1.
This unit is specifically design to work with PC sound cards, radio receivers and CD/DVD/Blue-Ray players.
Digitally Controlled 2.1 Channel Analog Audio Power Amplifier - [Link]