Look at companies that provide hospital grade electrical equipment. The requirements hospital's have are pretty tough. I have some hospital grade isolation boxes and they are great, with a low noise floor.
Where to buy a good quality wall wart
Sorry to seem so naive but I need suggestions for where to order a good quality wall wart power supply, to convert AC to 8-12v, 1A DC. A Google search turned up so many options that I just got lost in confusion. (It is to be used to power a USB-to-SPDIF converter.) Thank you for your advice!