After my adventure into more mechanical design with the construction of my speakers, I settled down into my usual comfort zone – electronic design. The speakers were built with quality in mind, so I needed an amplifier to complement them.
The main features of the amplifier are to take 2 optical inputs from my TV and a Chromecast Audio, decode, EQ and amplify for my speakers. The amplifier is capable of 150W/channel which is more than enough to find the resonant frequency of various objects around the apartment. A small screen and IR receiver finished it off and it was boxed up alongside a power supply unit which handles the 5, 12 and 36V rail generation.
The main amplification stage is provided by a TAS5624A Class-D which although audio purists would shudder at the idea, I thought provided enough quality to let the speakers shine. A TAS5558 audio processor provides all the DSP functions and the whole thing is controlled through a Teensy with TFT screen attached. It sniffs the IR commands coming from my TV remote so a second one isn’t necessary.
The PCB was hand assembled and fabricated in 2oz copper with matt black soldermask and ENIG – my favourite combination!
Fred Temperton 