The imAmp compatible with various Mobile audio devices is the best analog headphone amp as a portable Hi-Fi audio satisfying with sound quality improvement. As designed as a high performance Hi-Fi audio device, not using simple voltage amplification for a headphone, the imAmp features Quad OPAMP circuit design and powerful driving performance and is designed to be used as a Portable amp raising relatively low headphone output that most of the Mobile audios has up to Hi-Fi audio output. The imAmp provides a user using a high performance headphone with headphone-based high performance Hi-Fi audio environment in anywhere featuring dynamic headphone driving power, high sound definition, and analog-based high sound quality.