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]
It is a 2x56W stereo amp based on National Semiconductor’s LM3876T chip (they come in 2 versions T and TF the latter having an insulated case), this type of amp is also known as a gainclone because it is an improved copy of Gaincard amplifier. seriously this amp can outperform most commercial amplifiers/receivers (minus the video upscaling/switching) when built properly ie it has very low THD you will not be disappointed by how good it sounds.
56W LM3886 / LM3876 Gainclone - [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 a headphone amplifier based on BUF634 and OPA627. The amplifier operates in class-A.
BUF634 / OPA627 headphone amplifier - [Link]
This project is a Class-A Audio Amplifier based on 2SA1943 and 2SC5200 complimentary transistor pairs. This Super Class-A Amplifier is fully running at a bias of about 1.65A @ 35V, which it resulting in about 58W of continuous dissipation per transistor in the output stage. In this condition, you can highly imagine that the heat sink runs in a hotter temperature, where it can reach approximately 40 Celsius degrees!
Super Class-A Amplifier – [Link]
This project is a homemade speaker. RobertG writes:
It’s a simple speaker, that may be build at home from inexpensive and freely available materials: magnet, cardboard and tape, isolated wire from signal transformer and mini-jack cable from broken headphones.
Homemade speaker - [Link]