Posted on Thursday, May 26, 2011 • Category: Amplifiers
Gainclone amplifiers have very few components and this one is based on the National Semiconductor LM3875 IC. The PCBs and components are very simple and quick to make, only took about 20 mins to assemble both amps and rectifier board. DC offset was about 80mV on one channel and about 40mV on the other. I used the optional Ci capacitor in the national datasheet for the IC which reduced it to between 0-4mV:
This is the capacitor I chose, its an Elna Starget (expensive). The case was MUCH more time consuming and difficult to make though. I bought all the aluminium from a scrap metal yard including the heatsink. I got my aluminium panels cut at a sheet metal shop as I cant make straight cuts with a hack saw.
Build Accurate LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and reset function to make sure the readings are as accurate as possible ... [more]