LM3886 Gainclone amplifier

My first LM3886 'Gainclone' amplifiers, originally intended to be two separate monoblocks that would each sit on top of a speaker, but then combined into a single 3U enclosure instead.

I used two matching offcuts of aluminium angle to serve both as the bases of the enclosures & as the heatsinks required for the LM3886 ICs. The original vision was to then finish the enclosures with some sort of vented top, front, back & sides.

I managed to drill all of the mounting holes through the aluminium using an electric drill I got off Freecycle & which was so old the chuck was stamped 'Made in West Germany'.

I learned an important lesson about the ratings of transformers, as when I calculated what the DC rails after rectification would be I didn't take into account that the transformer datasheet assumed 230VAC across the primary winding. Where I was living at the time my AC supply hovered around 248V & as such the LM38876 ICs were being run very close to their maximum ratings.

This first LM3886 project lived on in my second as I resued the Nichicon filter capacitors in my LM3886 Gainclone 2.1 amplifier in 2020.