Furman Elite 20 PFi - Hummmmm

A while back I purchased a used Furman Elite 20 PFi for a questionably low price that represented little risk. The unit emits a steady audible, but not distracting for music, hum. I have opened it up and tried to determine the source of the noise, but have not had much luck. Slightly concerning was that the unit had clearly been opened before. There were cut zip ties laying about, and after some research it appears these were from the chokes, which were now unencumbered. I re-secured these with two ties apiece, although I now see an online photo showing four ties on each.

Anyway, the sound is not a distraction like I said, but I am curious if it is adding noise to my lines or represents a safety concern. If it matters, I have a dedicated line, and I believe relatively clean power.



I don’t think it’s an issue, but you may have DC on the line or a bad neutral.

Turn off everything else in the house and see if the problem goes away.  This should help you discover if you have any particular device putting DC on the line, LED power supplies are notorious as are PC supplies. Also measure the Neutral to Ground voltage, should be 2 V or less, 0V ideally.

If it’s still humming, find a way to measure each leg to neutral, should be the same.

My Elite is dead silent. It’s the Furman voltage regulator which audibly hums at times.

Thanks Erik, just the man I wanted to hear from. I have on of these 

 laying around, I will put it before the Forman and see if it cleans up the hum from potential DC. Will also test the neutral/ground.