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]
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]
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]
Most of the work that I have done in the past with vacuum tube and solid state electronics has been repair. So, I have ventured into the realm building. This is actually my second build (I’m still getting the bugs out of the first attempt) but I have applied all that I learned from mistakes to this build. Building from scratch is nothing like repairing. It takes time, a lot of thought and reasoning go into a build no matter how simple it may look.
6v6 Stereo Amplifier - [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]
The amplifier is based on the 12AU7 valve (part number ECC82 in Europe). The schematic came from here, it’s a nice kit, but lacked a power supply and the layout wasn’t quite what we needed for kits in TinkerSoc. I added a LDO 12v regulated power supply, an input volume control pot and kept the design single layered (with one jump). The final schematic can be viewed here
Tube Amplifier - [Link]
The CMoy headphone amp is a popular headphone amplifier that is small enough to carry everyday and powerful enough to drive headphones at higher levels than normal. Most headphones and most sources will get along ok, but there are players with weak output, and high end headphones typically give up efficiency for the best sound.
The CMoy amp was originally designed by Chu Moy, and at this point there are hundreds of variations with different components, layout, and features. Sometimes, users simply swap op-amps for a different sound and performance. This circuit uses op-amps to directly drive headphones, something they are not designed to do, also, some of the op-amps used are not even designed for audio applications!
Here is a simulation of ½ of a CMoy amp. It outputs over 4V from a 0.4V source. It provides decent audio fidelity from just a few small and inexpensive components. In the last few years, CMoy style headphone amplifiers have been very popular with the DIY audio crowd to increase the audio output to some of the larger and higher impedance headphones available.
DIY audio enthusiasts typically stuff these components into an Altoids tin, other tins, or other small project boxes. The CMoy style of amplifier is versatile enough to fit into many different form factors. Users also determine the container based on what features they choose to include with their circuit. They might add features like bass boost, DC input, and rechargeable batteries.
CMoy Headphone Amp - [Link]
Have no fear… even if this project sounds complex, you’ll easily learn in this article many things about high speed electronics and PCBs. In fact, my goal here is to teach you some basics about all the new problems that arise when you’re dealing with GHz signals
Amplifying nanosecond pulses for quantum physics experiments - [Link]