Vintage amplifiers that could challenge or approach current state of the art amplifiers

[RKV1]

Actually, there are some Adcom products that are exceptionally difficult to repair when they fail, even in the absence any SMD parts. E.g. it required significant money and time to bring this power amp back to life: Adcom GFA 585 (part 1 of 3)

Yes, the capacitor plague of the early 2000's infected Adcom's too.