The amplifier design includes not only the final stage of the source (rectifier, filter) and protection against DC voltage output amplifier and speaker connections delayed. As already mentioned, the amplifier is designed as a single-module. This means that on one common board rectifier, filter capacitors, protection And definitely amplifier. Regarding the components of the external solution, the solution based on the original Mr. Marshall Leach.
275W Leach Amplifier – [Link]
For a long time I needed a good programmer pussy, even if it is programming, so from time to time the application gets where it is used. So I decided to build the programmer. I chose between a couple of projects from different authors, but eventually won PICkit2. Microchip released the schema directly in the user manual for the programmer. On the Internet there are multiple versions of the programmer, it’s usually cropped version of the log analyzer features, UART terminal, etc., 12V inverter is a modified version of it and control the MOSFETs, unlike bipolar transistors used in the original design.
PICKit 2 CLONE – [Link]
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]
This Arduino can be used for old school prototyping as well. Just use it as a standard ATmega8 and program it with the ISP connector. And it is one of the cheapest Arduino boards, that you can get. Arduino is a great prototyping platform and most of you probably know already about it. If not, check out the Arduino pages and the Arduino playground and dive into it.
Arduino Breadboard Clone – [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 entry for the 555 timer contest is from Andrew Smith who built a motion activated switch for a digital camera. The 555 timer is operating in monostable mode which is triggered by a PIR sensor when motion is detected. The monostable output of 555 then activates the camera through a remote.
555 Contest Entry: Motion activated camera – [Link]
555 timer based AM radio receiver published on Tube Time is one of many entries for the currently running 555 contest. This project uses a 555 timer as AM demodulator plus amplifier to drive the speaker. The radio signal is tuned with an LC tank circuit. The 555 timer is configured as a PWM where a ramp signal is created with a capacitor and a potentiometer. The radio signal picked by the LC circuit is superimposed on the ramp signal which varies the duty cycle of the output PWM wave. The variation in the duty cycle corresponds to the audio signal in the radio waves.
555 Contest Entry: AM radio – [Link]