Looking for a Quiet Power Supply After Two Noisy Models

I've had issues with coil whine on my previous power supply, the RM850e ATX 3.0 850W, and replaced it with a be quiet! pure power 12 m 850W. Unfortunately, this new unit has also become noisy after just six months, even when idle after a restart. The noise isn't coming from the fan since it remains the same regardless of fan speed. Is there a power supply that is almost guaranteed to be silent? Any recommendations would be greatly appreciated!