isolation transformers hum


my giant Noisetrapper 2000 isolation transformer hums audibly, and the hum gets louder as the load on it increases (e.g., turn on tube amp in standby, it hums; switch it on all the way, gets louder). Do all isolation transformers hum? Could it be caused by dc on the line, that could be filtered out by one of those ps audion dc filter devices?
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Showing 1 response by ngjockey

Not familiar with that brand and couldn't find info.

Most of the better brands are rated for below 50dB, under 5KVA. I've got two (5000VA and 500VA) and can't hear either without a stethoscope. A third should be soon.
Hasn't always been the case and had one that was always noisey but I got it for free, so it didn't hurt to abandon. The big one has made noise when wired one way, but only after I moved to another house. Unpredictable.

Saturation and noise can be caused by DC offset and the PS Audio Humbuster can reduce that but it's only one of many factors.