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

@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.  

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. 

@djones51 Thanks very much! 

@djones yes. I purchased them from Apos as part of their bundle with the A90 & D90.

@audioville I ended up getting a 3rd A90 (after considering other amps) and so far, so good. Depending on where / when you purchased the A 90, you may still have a warranty (I think it is a 1 or 2 year warranty?). I purchased the Topping "ensemble" D90 MQA & A90 from Apos. They were very slow to respond but they eventually replaced both failed units. (They don’t reveal if their online support is in China or stateside, or if stateside has to get approval from the China manufacturer so it’s odd. Their email support comes in flurries at odd times suggesting they're based overseas; it is messy and disorganized.)

I’d also check if you are using an aftermarket (Hart, Periapt, or other) balanced interconnect and/or headphone cable whether or not it "shorted" and caused the problem. This is hard to diagnose and hard to find an engineer on forums who might explain if this could even cause the issue. At some point, you stop wasting time on what happened and just replace the cables & get a new A90 and get back to music. :-) I very well may be wrong, but I am suspicious if a cable could cause a short or damage to the amp.

I hope you are able to get it replaced. When it works, I love the A90 & D90!

UPDATE, thanks all for comments. I did in fact receive a 3rd Topping A 90 and it has been working so far. 

Enjoy the music!