DAC repair/troubleshooting in New England

I purchased a DAC in Taiwan quite a few years ago. It’s a dual TDA1541A, with a tube output stage. Really nice construction and components. Pictures are linked below. 
It’s always had a significant hum. I love this DAC and would really like to get rid of the hum, but not savvy enough troubleshoot myself. 
Anyone know a good place within reasonable driving distance from Central CT that would be capable of this?



Is there a usb input? Are you using it? If so, I will suggest something that may eliminate it. I am assuming you are referring to a hum through the speakers? The woofers? Like a ground loop 60 htz hummmmm.....
It does not have a USB input, just optical, coax and balanced. 
The hum does sound like a 60hz ground loop, or at least I think it does. 
Try just unplugging the input cable you are using with the unit on and off. Does the hum go away?