The amp described on this page, is a very simple poweramp based on the National Semiconductor chip LM3875.
According to National it's a chip meant for TVs, compact stereos etc. But many people claim that these
chips are great high-end amps...
So I decided to try building one. The "design" work was quickly done, as I just used the guidelines and sample circuit of the datasheet. I designed a small PCB for the amp (I'm lazy), and I made it double sided to make it easier to keep all the ground lines separate, as recommended by National.
The prototype board can be seen below with a 100VA toroid I used for testing.
The frequency responce (at about 7W) was 17Hz-110kHz at -1dB and 7Hz-220kHz at -3dB.
So is it the best amp I have ever heard? No, but it still sounds great. If you need a simple trouble-free power amp for something, this could be it.
Files for downloading (all in PDF format)
You can get ready-made PCBs or kits here.
Comments? Questions? Just send me an e-mail!