amplifier - Reducing noise in an audio amplifer using opamp - Electrical Engineering Stack Exchange
Headphone Amplifier Donner 4 Channels Metal Stereo Audio Amplifier,Mini Earphone Splitter with Power Adapter-4x Quarter Inch Balanced TRS Headphones Output and TRS Audio Input for Sound Mixer-DEL-4 - Walmart.com
Donner Headphone Amplifier Professional Ultra-Compact 4-Channel Stereo – Ushopsound
Amazon.com: 2 in 4 Out Sound Mixed Distributor Lossless Volume Adjustable Sound Signal Amplifier with 3.5mm Headphone Jack, Large Dynamic Fidelity Output, Gain 14DB (US Plug) : Electronics
LME49600 as headphone amplifier - Audio forum - Audio - TI E2E support forums