As a follow-up to my post earlier in this thread, I purchased some Cooper RF9540-N switches earlier this month. The switches seem to be good quality and the z-wave control with instant status is nice. The problem is that all my dimmable LEDs connected to these switches buzz unacceptably, throughout all levels of brightness. I have tried 7 different brands of A19-style dimmable LED bulbs, including CREE, Philips, Sylvania, Utilitech, EcoSmart, etc. Every bulb buzzes, although the EcoSmart bulbs were much quieter at full power than others, but the models I tried seem to be discontinued. I’ve tried different fixtures on different circuits. I’ve tried 3 different RF9540-N dimmers thinking I had a bad one or two, but they all do it. Although, they are all from the same date/batch. I tried a non-z-wave Lutron C*L Maestro dimmer. Same behavior.
I’ve spoken with tech support at CREE, at Cooper, and at Leviton. Cree says the bulbs will hum less on an ELV dimmer. Not that they won’t hum, but they’ll hum LESS. Cooper says it’s normal to have the bulbs buzz on a dimmer. Leviton won’t assure compatibility of their switches with LEDs. Still, I think I’m going to try the Leviton VRE06-1LZ, (an ELV dimmer) to see how much less the bulbs hum.
My wiring is right, I have neutrals on everything. The buzzing and flickering is not OK with me or my wife.
I’m at the point of sending everything back.