Profile: Audio Design Associates, Inc. offers structured wiring systems, multi-room receivers, pre-amplifiers, power amplifiers, line-level isolation amplifiers, digital to analog audio converters, analog to digital audio converters, speakers and line level switchers. Our ISO-2 line-level isolation amplifier optically isolates its two-channel line level input from its output. As such, there is no electrical connection across the device. Audio is transmitted from input side of the ISO-2 to the output side via opto-isolators. This makes the ISO-2 ideal for removing ground-loop hums. The ISO-2 is also useful in getting rid of ground-loop hums when the line level audio signal is run from one device to another, where the two devices are operating from different AC outlets. LLS-2 is a two-pole line-level switcher that can be used to switch two completely different line-level audio signals. It can be used to provide a source audio override into a system whose inputs are all used up. Because the LLS-2 is a four-pole two-way switcher, it uses independent grounds for each channel.