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]
Voice Module 60 Sec project will playback and record up to 60 seconds of voice message. This circuit is an excellent choice to add voice to your project.
60 seconds Voice Record – Playback module - [Link]
This project is intendant for use as low frequency class AB audio amplifier.
Project is built around TDA2006 PENTAWATT package. TDA2006 provide high output current and has very low harmonic cross-over distortion. Further the device incorporates an original (and patented) short circuit protection system comprising an arrangement for automatically limiting the dissipated power so as to keep the working point of the output transistors within their safe operating area. A conventional thermal shutdown system is also included. The TDA2006 is pin to pin equivalent to the TDA2030.
12W Audio Amplifier - [Link]
This project is a message recording board capable of recording 120 secs of audio. This project is designed around ISD25120 which can store 120 Seconds audio. Recording and playback operations are controlled with tact switches. The kit has an onboard microphone and LED to indicate the functions of Play and Recording. IC has a re recordable non-volatile memory which means that the message will be stored even after the units are turned off and even when it is turned on again.
120 Seconds Voice Record – Play Back - [Link]
Rugged, great sounding boomboxes for all of life’s adventures.
DemerBox is a rugged, great sounding, water-resistant boombox that you can put things inside. The Bang is our single speaker model. Its about the size of a lunchbox but don’t let its svelte size fool you. The Bang gets loud, has tight punchy bass, and pleasing mids and highs. The Big Bang is our two speaker model. Its about the size of a soccer ball. The Big Bang gets louder than The Bang, and because it has two speakers, you get stereo separation and a little more detail in the music.
DEMERBOX – Rugged Wireless Boomboxes - [Link]
Rupert Hirst writes:
A long awaited refresh, to my previous “Anti Thump” headphone output delay circuit, designed back in 2011.
The Idea behind the circuit is to introduce a small delay, during initial power up, to electrically isolate and protect equipment connected directly to an amplifier. Often, during power up, amplifiers can produce an audible thump, through speakers or headphones. This can lead to damage of the connected equipment over time.
Thumps and clicks will occur when the supply rails voltages are too low to allow the amplifier to control its output voltage.
As the circuit has an immediate disconnect when powered off, most instances of turn off thump are also dealt with, such as output capacitor discharges.
Audio: Headphone “Anti thump” delayed output rev 1.1 - [Link]
by Giovanni Militano @ diyaudioprojects.com:
I’ve always enjoyed electronic kits of all kind and like many of you will credit them for the foray into DIY audio. Over time as my DIY skills matured I found myself taking the DIY route for projects far more often than relying on kits. While I will always enjoy electronic kits, I generally won’t try one out unless there is something really unique about the kit. When I saw the Gobo Stereo Audio Amplifier kit from boxedkitamps.com, I was immediately intrigued by the unique looking enclosures available with the amplifier kits. Shown in Photograph 1 below is the completed Gobo Stereo Audio Amplifier kit with a translucent blue acrylic enclosure. The choice of enclosure finishes for the Gobo stereo amplifier kit include blue, dark grey and orange acrylic and bamboo.
Gobo Stereo Audio Amplifier Kit (LM1875, 15W, Class-AB) - [Link]
STMicroelectronics’ has introduced a new digital audio processor with a >100 dB SNR and Dynamic Range. The device can process most digital input formats including 6.1/7.1 channel and 192 kHz, 24-bit DVD-audio and DSD/SACD. When configured in a 5.1 application its additional 2 channels can be used to supply audio line-out or headphone drive.
The STA311B is a single chip solution for digital audio processing and control in multichannel applications, providing FFXTM (Full Flexible Amplification) compatible outputs. Together with a FFXTM power amplifier it can provide high-quality, high-efficiency, all-digital amplification.
High Dynamic-Range Audio Processor - [Link]
w2aew @ youtube.com writes:
This video presents a simple automatic audio volume leveling circuit. The application that prompted this is a police/fire/emergency scanner. Often times, different services will have different volumes in the receiver – so adjusting for a comfortable listening level on one service/station will often lead to other services being too loud or too quiet. This circuit will automatically adjust the volume of each received signal based on the signal’s peak amplitude. Similar circuits have been widely published, so there’s really nothing new here – just a quick tutorial and demonstration of how this circuit works. An arrangement of capacitors and diodes are used to implement a peak detector to measure the input signal amplitude. The dynamic impedance of diodes is controlled/changed to adjust the signal level. The result is a leveling circuit that has a very wide input dynamic range with a near constant average output level.
Circuit fun: Automatic audio leveling circuit - [Link]