Odd Buzzing/Humming from 7075

I have had my 7075 for just a few months and within the last month or two it makes an intermittent humming or buzzing sound that is starting to make me worry since it is coming out of the actual unit and not my speakers. Everything seems to work fine and I have not noticed any performance difference. Just wondering, should I worry about this? Is this normal? Is there an easy fix or should I send it back? Thanks for any input.

Same problem here, after a bit more than a year without problem.
I logged a ticket with outlaw and got the response below.
Now, the strange thing is that they also CLOSED the ticket so I had to re-open it to respond(!). I did not get any response to my response

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Hello Fellow Audiophile,

Hum from the unit itself is indicative of one of three possibilities.

One if which (a defective transformer) is permanent and would not go away without corrective action.

The other two can occur intermittently.

The first, and more common of the two, is voltage sag. Sometimes a voltage stabilizer or relieving the load on the corresponding circuit will resolve the transformer hum.

The second is DC on the AC power line. This type of hum can be distinguished by the nature of the hum itself. Voltage sag typically results in a hum that stays consistent in frequency and intensity. When DC is the cause of the hum, the noise will change in both frequency and intensity when it is present.

If you have encountered DC on your AC power line, you'll need to remove it with a dedicated DC filter.

Please describe the hum you are hearing so that we can suggest some troubleshooting steps.

Thanks and regards,

Scott