ARC 100.2 pop and hum

I just got a new ARC 100.2 solid state amp. When I first turn it on, there's a pop or thump in my speakers. Then, after the protection circuity goes off and the amp is "live," there's a hum in the speakers that can be heard as far as about 3 feet away from the speakers. The hum is evidently the sound of the amp. Getting close to the amp, I can hear the sound of the transformer(?), which is the same hum that's coming through the speakers. I've tested all of the possibilities of something else causing the hum: I removed the interconnect with the preamp--still the same hum; I used an adaptor or "cheater" plug to avoid the ground in the circuit; I plugged the amp into a separate circuit. Despite all of these different configurations, the same sound of the amp comes through. Is this normal? I'd expect it to be nearly dead silent when nothing's going through the amp, but maybe I'm wrong. Please let me know of your experiences with this amp and other amps. Thanks.
My new 100.2 also pops when turned on, however it is dead silent in operation.
Contact Leonard at Audio Research (763)577-9700. He's the head technician and very helpful.
Hi Dave,

The hum is not normal. Contact ARC and send the unit back. Something got damaged in shipping.
Try it at another location and see if it still hums. You may have a light with a dimmer that is causing it. I had this exact thing happen when I was showing my amp to someone that was interested in buying it. It did it everywhere in the house! It was so bad, he actually thought something was wrong with the amp. I noticed a light with a built-in dimmer and disconnected it from the wall and it stopped immediately.
Good luck!
I had a 100.2 and was told by ARC that some transformer hum is normal.
The slight pop when you turn the unit on is normal, but the hum that you describe is not. I leave my 100.2 on all the time and it is quiet.
The turn on noise is normal. The unit runs dead quite during oreration. I also delete the groung plug and leave mine on 24/7. Sounds like something else is wrong.