The company Roemtech (www.roemtech.com)  is a longtime Bitlogix partner for classroom control systems and NetControl network projector control software. They recently introduced a new stereo amplifier/mixer with a very interesting Hummbuster technology.  This new technology is switchable allowing flexibility in resolving ground loop issues, should they arise. The PMA-245H is a dual input, 18 volt, 45 watt, plenum rated stereo amplifier/mixer. Enjoy the video presentation.

Here is the product link: http://www.roemtech.com/classroom-audio-amplifiers.html