Calling the OPPO HA-1 simply a headphone amplifier is kind of like referring to my smartphone as just a cell phone. Yes, the HA-1 is technically a headphone amplifier, but for $1,199 you get a lot more, including a state of the art DAC, stereo preamp functions, and a few other nice surprises in a compact chassis. In short, the HA-1 is everything a 21st century stereo preamp should be. Curious to know more? Click to keep reading. Discuss "OPPO HA-1 Headphone Amplifier Preview" here. Read the article.