Topping A90 failure issues. Should I try a 3rd A90?

MOVE ON!!

@dreas  We have a new D90 (non-MQA) that had some odd distortion issues when we got it. We were running it from the USB port of our shop Mac Powerbook. Apparently the settings got scrambled and we had to reset what was being sent to the USB port. This cleared up the bursts of static and outright distortion. You might take a look and see if this is what is going on. We've not had a lick of trouble with it since.

Thanks, sincerely, for everyone's comments.
@atmasphere long story short, I've diagnosed 2 different laptops. I did have a static issue with a new Dell (I think it's their UBS audio -- part of the motherboard -- that's frankly cheap) but an 7 year old Lenovo X1 Carbon works great. I tried 3 different A-B USB cables and 2 of ifi inline jitter devices. No help. But this is different. After a loud static discharge, one channel went out. The volume knob - turning it down or up -- made it worse. I'm 90% sure it's the Topping A90 has a problem. As to an eariler comment from @ audio2design there is no external power supply on these. The A90 & D90 have their own. (Earlier Topping models did have an external power supply). Again, thanks to all. I loved the idea of this set but I think there's a build issue? Who knows. 

@soix valid point but I'm not sure what could contribute to it from my setup. I use it as a standalone setup, the Topping A90 & D90 with the recommended XLR balanced cables. The only inputs are a USB A-B connection to the D90 (DAC, not amp) and power cords into a separate power conditioner/strip.  

Have you used the same balanced cables on both units?