After I built several LM3875 and LM3886 gainclone amplifiers, I was totally impressed by their audiophile sound quality. My design goal is to create a audio power amplifier that can deliver 300W into my 4-ohm DIY speaker with low distortion. I want it to produce deep, tight and punchy bass while keeping the excellent mids and highs from my other gainclones. My design uses a PCB to hold 3 paralleled 3886s (i.e. PA150), and then I use the DRV134 to bridge 2 of the PA150 PCB boards. The function of DRV134 is to convert the un-balanced input signal to a balanced signal, so that the non-inverted signal is fed to one PA150, and the inverted signal is fed the another PA150. One of the PA150 is connected to the speaker’s positive input, and the other PA150 is connected to the speaker’s negative input. Because of this push-pull configuration, the total gain of the amplifier is doubled. Each PA150 has a gain of 20, so the gain of the BPA300 is 40.
300W 6x LM3886 Bridged Power Amplifier – [Link]
400W Stereo Audio Amplifier based on the original Marshall Leach involvement, but has made some improvements. Regarding the power supply voltage to the +-75V. VC comparing the performance of the modified Leach 700W/2R on one common board of both channels, as well as protection and control circuits for the fans. Compared to the 700W version a bit different in wiring. Because some things in the 700W version is completely tightened to perfection.
400W Stereo Marshall Leach Amplifier – [Link]
This audio power amplifier project is based on LM1875 amplifier module from National Semiconductor. It is able to deliver up to 30W of power using an 8 ohm load and dual 30V DC power supplies. It is designed to operate with minimum external components with current limit and thermal shutdown protection features . Other features include high gain, fast slew rate, wide power supply range, large output voltage swing and high current capability.
25W Audio Power Amplifier - [Link]
This audio amplifier project is a class AB audio power amplifier using a TDA2003 module power amplifier. It is easy to construct and has only a few external components. The module is designed with short circuit and thermal protection. It can drive loads as low as 1.6 ohm and is capable of delivering over 10 watts from a 16 V DC power supply. Figure 1 shows the TDA 2003 packaged and pin configuration.
Simple To Build 10 W Audio Amplifier! – [Link]
Many electronic projects require the use of a small audio amplifier. Be it a radio transceiver, a digital voice recorder, or an intercom, they all call for an audio amp that is small, cheap, and has enough power to provide adequate loudness to fill a room, without pretending to serve a disco! About one Watt RMS seems to be a convenient size, and this is also about the highest power that a simple amplifier fed from 12V can put into an 8 Ohm speaker.
LM386 Amplifiers – [Link]
The following is a 70W amplifier based on a popular TDA7294 chip. Main technical characteristics of the amplifier are as follows: input resistance – 22 kOhm input voltage – 750 mV nominal output power at 4 ohms and THD 0.5% – 70 Watts Frequency Range – 20 … 20000 Hz supply voltage – ± 27 V, quiescent current – 60 mA. The amplifier has a built-in thermal protection, and protection against overload and short circuit in the load.
70W TDA7294 Amplifier – [Link]
This project is an easy audio amplifier based on 8 pin DIP LM386 integrated circuit.
The potentiometer is the volume control. The heatsink is screwed to an LM7812 12V voltage regulator. There are a couple of caps and a diode on there. The wire with what looks like gum on the end of it is actually the headphones jack wire with a three-pin header molded onto the end using that really cool putty “as seen on TV” that you knead together and it forms really hard parts. I used it to protect the super-thin wires of the headphones jack. The little chip on that board is the LM386. The red- and black-tipped wires coming into the top of the breadboard just left of the diode and the voltage regulator are the leads from a Radio Shack 12V, 500 mA wall wart.
LM386 Easy Amp – [Link]
A Class-D amplifier operates the output transistors as switches instead of as variable resistors, as in more traditional amplifiers. In doing so, nearly all conduction losses in the output power devices are eliminated, leading to a very efficient amplifier. [via]
DIY class-D amplifier – [Link]
This is a DIY Headphone amplifier based on OPA2134 op-amp by Texas Instruments.
Apart from running headphones crystal clear, another advantage is that it can act as gain enhancer for my gainclone when watching movies from PC.
Cmoy DIY Headphone Amplifier - [Link]
This project is an audio amplifier rated at 100W. An audio amplifier is an electronic amplifier, which it used to amplify low-power audio signals (20 hertz to 20,000 hertz) to a level that suitable for driving loudspeakers. This amplifier uses the TDA7294 IC from SGS-Thomson which it’s a 100 watt operational amplifier. Check construction details on the link below.
100W Audio Amplifier - [Link]