Shure SCM268 analog mixer - 4-channel

The SCM268 microphone mixer features six transformers inside: four transformer balanced XLR microphone-level inputs, one transformer balanced XLR mic/line output, and one internal low stray field, toroidal power transformer. All those audio transformers provide protection from RF interference, prevent ground loops, and make the SCM268 exceptionally quiet. The internal toroidal power transformer means you no longer have to deal with that annoying "wall wart".