Electro-Harmonix Headphone Amplifier Compact Studio Headphone Amp. This Electro-Harmonix headphone amp delivers clear, low-noise amplification for headphones in a small, easy-to-use format. Ideal for musicians, home studios, practice setups, or monitoring applications where clean sound and portability matter. Features simple controls for volume adjustment and reliable Electro-Harmonix build quality. Condition is rated 9–10 with minimal signs of use and no functional issues. No major scratches or damage observed. Great option for anyone needing a dependable headphone amp without taking up much space.