Stereo Amplifiers: NAD C315BEE vs. Yamaha RX-497

The Yamaha product is both an amplifier and a tuner, while the NAD is just an amplifier. Since the prices are similar, this suggests that you're getting a better amplifier for the money with NAD than you are with Yamaha, since some of the costs of the Yamaha goes toward its tuner capabilities.

The NAD has a THD of 0.02% compared to the Yamaha's THD of 0.04%. THD is a measure of the amount of noise an amplifier produces. The Yamaha produces twice as much noise as the NAD. Note that you may not be able to hear much difference, but it does suggest the NAD is better quality than the Yamaha.

The NAD has a "tone defeat" feature, which is a feature I like to have in an amplifier but may not matter to some. Ideally, a good amp and speaker combination should sound good without having to use tone controls (though in reality this isn't always the case). Also, enabling the tone defeat feature may likely reduce the noise produced by the amplifier since tone controls tend to introduce more noise.

The Yamaha may be a louder amplifier than the NAD, according to the wattage specification. However, you can't always tell by the wattage. My guess is the NAD will be loud enough.

Yamaha is a popular and consumer-oriented brand with a wide variety of products, while NAD is focused mostly on audio products. Companies with a specialty focus like NAD often produce better quality products.

The main concern with the Yamaha is the quality of the amplifier, and the main concern with the NAD is whether or not it's loud enough. Of course you can always try the NAD to see if it's loud enough.

In short, the NAD amplifier is better than the Yamaha amplifier. So if you don't need a tuner, then NAD is the preferred choice.