Many people already use powerful amplifiers that are capable of blowing up their speakers when driven at full volume, I don’t see them stopping to use those amplifies anytime soon, they just have to be careful with the volume control or use it in low gain mode, I thought this was common sense in Audio. I don’t see why the topping EHA5 should be treated differently. Topping got a bad reputation after the L30 problem with it sometimes outputting DC instead of AC but that can’t possibly happen to the EHA5 because DC can never physically pass through a transformer let alone be stepped up by it, if it did, Tesla would have never been as famous as he is and USA would probably still be powered with Edison’s DC.
I have a Topping LA90 running my STAX converter with Lundahl Transformers and it has impressed me with its build quality and performance.
I don’t doubt Spritzers experience in the STAX arena but I would just point out he has been solely looking at the output side of the transformers from what I read. As you said the transformers already block DC by nature and there may be plenty of protection on the low voltage side in Toppings custom ICs… They seem similar to the LA90 which has plenty of protection.
As for the audio performance, still early days but yeah we know this isn’t going to complete with Lundahl transformers especially at the price point.