These units take a single input and pass it through four or six individual amplifiers, thus providing us with separate, isolated outputs. Those outputs don't load each other down. Whenever a signal is distributed to more than one place, a distribution amplifier (or "D.A.," for short) is used. There are different units available for audio and video. Some audio distribution amplifiers are "stereo," which simply means that there are two monaural units in one package. So, if you're sending a source to more than one place, use the spare D.A.s available at your patch racks.