How loud is your Agilent E3600 series power supply?

[amahon]

I just unpacked and powered up a new E3647a and it has an unusually loud mains hum... akin to a cheap florescent light fixture (ie. with a poor ballast). That is with the outputs off. When under load it changes somewhat but not significantly. Definitely sounds like transformer noise / vibration. Otherwise, all else seems to be ok.

It is many times louder than my Rigol DS2072 scope, my laptop, or anything else in my office for that matter. Is this normal?

Thanks,
Andrew

[NickAmes]

I have an HP 6234A (a older model than the E3600 series, but of a similar design). It has a noticeable 60Hz hum when on. The noise doesn't seem to change under with load.