Nuts and Volts - March 2015

for the inputs and attaches to a socket on the left side of the board; on the other side is a barrier strip with screw terminals for the left and right speaker outputs and power supply connection. That's one of my favorite things about this module since it will make it so easy to integrate it into other projects with a minimum of messing around with external controls and switches. It'd be easy to attach a volume control pot to the input if needed, but I'm envisioning this one being great in applications where the audio signal is being controlled by a pre-amp or receiver — like the Wi-Fi Internet radio project shown in Photo 14.

The Tripath TA2024 is a decent little chip itself. It can deliver up to 15W into a four ohm load at 10% THD+N, but is rated for "audiophile" quality sound at up to 9W at 0.04% THD+N (Photo 15). Naturally, this is going to depend on the implementation, which can really throw it off if it's done poorly. Fortunately, though, this module delivers pretty close to its specified performance. It's close to the reference design from the datasheet, as well (Photo 16, Photo 17, and Photo 18).

I'd call this a very solid implementation; performance is very close to the datasheet figures. While everyone's ears are a little different, most people can't pick out distortion below about 1% unless they're specifically looking for it. This module delivered 11W into a four ohm load at only 0.7% THD+N. At 9W, it was well into the audiophile quality range, with only

0.082% THD+N — a bit higher than the theoretical figure of 0.04% THD+N, but very respectable nonetheless. This is a good little board!

One thing about this particular module ... it only delivered the low distortion into a four ohm load. It's rated for much less power into an eight ohm load, but comparing performance at 5W, the module delivered 0.55% THD+N which is much higher. Certainly listenable,