When sourcing a 5.1 channel amplifier, you must prioritize Rated Output Power (RMS) rather than peak power to ensure stable performance. Look for a minimum of 100W per channel for the front speakers and a dedicated Subwoofer Pre-out or Powered Output. Key features should include HDMI ARC/eARC support for modern TV integration, Optical/Coaxial inputs, and Bluetooth 5.0 or higher for wireless streaming. For karaoke specifically, ensure the unit has at least two 6.35mm microphone inputs with independent volume, echo, and reverb controls.