You can see that one or two of the other 80V caps are ready to pop.
Run too close to the voltage limit. they were getting gassy.
A manufacturer of those caps was absolutely full of it, or a parts supplier for that capacitor company was full of it, or..NAD was penny pinching and purchased dicey product, or the capacitor manufacturer flat out lied their face off about their quality standard.
Or some combination thereof. All I can say is that some of the decisions made, from/during that time period, have really hounded the company. eg, the 370 and associated power amp design...I’ve seen far too many of them with the same failure. Additionally, with shorted/dead caps, from the same company/source. Four in one year. I expect to see more.
It is many years down the road, though, so not really all that predictable. But there is a time to be careful about expenditure and a time to throw the penny pinching accountants out the nearest window.
My Best quick guess is that someone decided to try and save a nickel on capacitor costs, and took a shot, they took a swing, they took a flyer... and it worked.
For a while. for about a decade. Now that accounting decision has come back to bite them a bit...
Anyway, no one is perfect, and other than this blip, NAD has done really well. Sooner or later all manufacturers get bit by this sort of thing. It is just a matter of time, but is also tied to design and parts decisions. and it is not always the engineer or designer at fault. It can be accounting that is tied to parts costs, which can make iffy decisions. To do the right hing and satisfy customers who know little about the insides.. but.. a lot about prices they pay. It's a difficult balance at best.
