I have to disagree with age meaning an automatic dismissal by itself. If it sounds good it is good. Does the 500c get everything right? No, of course not, but does it make you smile and relax and enjoy fine acoustic music? Yes and very much so. I have spent zillions on high end in the past and locally have heard mega multiples of 100K systems and have been in this "game" since the 500c was new. If I am excited by what I hear I do not care what it costs, what technology is doing the magic, or what it is suppose to say about me throwing so much discretional income at audio (I am embarassed to say how much I did this in the past and, unfortunately, likely to do in the future). The most important tubes in the 500c, in terms of durability, the 7591s output tubes are in full production. Yet, the nuvisters are ones for example that could be hard to find but with thousands and thousands of 500C's sold that may not be the case for a few years. That said, try to find many solid state ICs replacements that are just 20 years old and you will know the value of discrete circuits. Elegant tube designs from ages past are around and in surprizing demand for a reason and it is not marketing by the likes of Sony, actually around dispite of it.