The Feonic audio drivers that will be put on the shop windows in order to produce the sound for the installation are all mono. However, for those shops that have sufficicent window space, my plan is to pair the drivers in order to produce a stereo image. In order to accomplish this I have purchased a number of extra stereo amplifiers, and it is these that I have been testing today. (I have opted to use the new TA2020 class T digital amplifier which has been getting very good reviews). Of the six that I was running tests on only five passed my quality control, and so one needs to be returned and its replacement can be tested along with the rest of my amps when they arrive.