What amplifier mode allows one input of a 2-channel amp to feed both outputs?

The correct answer is parallel. In parallel mode, one input of a 2-channel amplifier can effectively feed both outputs. This configuration allows the amplifier to drive two sets of speakers or components using a single audio signal, ensuring that both outputs receive the same signal.

When an amplifier operates in parallel, it takes the input signal and splits it to drive multiple outputs simultaneously. This is particularly useful in live sound reinforcement situations where you might want to send the same audio feed to different areas or to multiple speakers for a cohesive sound experience.

In contrast, series, split, and bridged configurations function differently and wouldn't allow one input to manage both outputs in the same way. Series configurations typically connect inputs end-to-end, split might refer to routing signals differently for processing, and bridged amplifiers are designed to combine two channels into a single output for increased power, not to share the same input across both outputs.