The PHDA02 - a reference class headphone amplifier with Stereo, Mono, and Dual Mono operation modes. In Stereo mode, the L/R input signal is fed to the left and right earphones while the volume level is set by the Stereo/Left control. The front panel inputs provide simultaneous connection of two headphones in parallel. In Mono mode, the left and right channels are summed, and the resulting mono signal is fed to both the left and right earphones. Again, volume is governed by the Stereo/Left control....