I installed ten WAC HR-8403 low voltage fixtures with 50W MR16 bulbs (WAC brand) and controlled them with a Lutron RadioRa dimmer.
Despite the fact that the dimmer is supposed to be fairly high-quality, I observed an audible buzz when the lights were dimmed. The buzz appeared to be coming from the 8403 transformers. Installing one of these 600W debuzzing coils made them dead silent! THIS COIL WORKS WONDERS and it's a very easy fix to boot.
Note that the coil does not ship with any enclosure. The installation instructions advice to install it in a junction box. A regular 4x4" box is too small, but fortunately a local hardware store offered a 4-11/16" by 4-11/16" metal junction box that fits perfectly.
BTW: If you consider the more expensive Lutron brand debuzzing coils, be warned that they have a temperature shutoff at 40C and installing them in some locations (like in the attic) may cause them to turn off by what is "completely normal" ambient temperatures for the location. The WAC coil does not have any limitations like this for placement.
By:Home Theater Fan , Homeowner (Wilmington, NC)