The NE5532 (or 5534) is still used today in high end hi-fi because it's simply a reference and a really musical opamp... When I had my DAC construction syndrome, I found it was certainly one of the best opamp, if not the best. And it has a 600 Ohms output load, so perfect for studio gear like lots of Neve studio channel strips. And, by the way, a 12AX7 tube dates back to 1947 and is still a reference today....