Posted on Tuesday, February 15, 2011 • Category: Amplifiers
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.
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]
