Changes in DAC Presentation - Need Advice

I have a voltage regulator on my line and notice a fluctuation of up to 10v.  It is rare that it will fluctuate more than 1v in a short period of time.  For a significant increase in voltage to occur, either an auxiliary power supply we need to go on/off line or a huge number of people would need to do something simultaneously.  Not sure this is terribly likely. 

Could be break-in, especially if it is going in the same direction (bright to warm or Warm to bright) every time your hear it change.  Do you notice a difference if the system is on for a while prior to listening or if your turn the system on fresh?  

Another obvious spot to look is the weak link in your audio chain which is that Mac Mini.  I talk to lots of people and more often than not, if something bizarre is happening in their system, a Mac Mini is involved.  Does anything else run on that Mac Mini?  If something else is taxing the processor, that could be your issue.   It would also explain why you might hear a change mid-song.  

@verdantaudio, my system is on 24/7 so I can't imagine there is much warming up as I listen. Regarding the Mac mini, nothing else is running on it except for Roon, but I'll definitely do some research on this. Thanks! 

@sbank, the OS/NOS light does not change. 

I have a T2 + upsampled  you didn’t mention how long you have had it 

it takes over 600 hours to fully stabilize with these  OX over clocks ,one reviewer in Europe documented this , you are supposed to not shut it off ,

or putin stand by , you should have a dedicated 20 amp line if possible .

Are you in the u.s ?  If so look up my user name and send me a message 8 can fill you in ,and you can tell me what you have or din5 have 

what kind of line conditioning, and usb cable ,if using a computer buy the Iris, or Hermes reclocker ,then you can run it direct the best I2S

From your description, my first guess woukd be breakin. A number of components I have owned have gone through flip flops in sound quality between 100 and 200 hours of use.

The second, and perhaps more likely is your Mac. I assume it is your streamer… PCs are not good streamers. They are noisy sources. There are dozens or more of background processes and other stuff going on. If it continues, I would recommend a good dedicated streamer of comparable or better value.