[Orpheus]

yes, the ar-1220 (and your 1215 probably) can physically vibrate. that's what big transformers do with high power. also, if you read the manual, it says it will vibrate when under-loaded too. so, if you just have a couple components plugged in, it will hum also.

i actually called furman, and they verified there's nothing wrong... they suggested me to put it in the "machine room." ha ha. yeah, right, like i have a machine room in my house. anyway.... i doubt you heard the mechanical energy in the form of noise in your headphones.... that's highly doubtful. these voltage regulators are used in some of the best recording studios in the world, and of course during touring. the noise either comes from elsewhere, or you're actually hearing the physical humming from the unit through the cups, or your ar-1215 is broken.

hirsch... don't worry, the surge protection's VERY good in all 3 furman units..... overkill. seriously, if lightning does strike, every piece connected to my power will survive. just i won't.

 

[88Sound]

Quote:

[size=xx-small]Originally posted by Hirsch[/size] diycable.com has a kit for a surge suppressor circuit designed by Jon Risch that works well ($125).

Thanks for the tip!

Quote:

[size=xx-small]Originally posted by Orpheus[/size] the noise either comes from elsewhere, or you're actually hearing the physical humming from the unit through the cups, or your ar-1215 is broken.

The noise can definitely come through the cups even with the Furman in a rack with the cover on. I believe with my AR1215 it is passing a very small amount of noise through the devices it's powering. The amount is so small that it is completely lost in the noise floor of most devices. This amount of noise would be no problem at all in a touring situation, however I would question the placement of an AR1215 in a world class studio powering a critical device. Other Furman products however might work perfectly here. It is also possible that my AR1215 is out of spec, although all of it's critical functions seem to be fine and I wouldn't hesitate to use it on stage.....any stage, at any rate the beer refrigerators are much louder.

There is one other possibility......This noise, so low as to be at the edge of my perception, is all in my mind....