Lifespan of amps and preamps?

They are like the pyramids ancient history its time to move on.

I've seen a 'new in box' Marantz 8B for sale recently. But I think having some history/experience with a particular model/brand really helps take the mystery/risk away from buying older amps.

In 2009, I bought a Carver TFM-35 that was still sealed in the box.  The only picture the seller posted was the box exterior. At the time good used versions of the amp were going for about $450.  Since I had owned the TFM-15 new back in 1994, I thought what the heck and just bought it for the 'buy it now price' of $575.  

Well, the sound of that amp really was great! The only thing it lacked was some bottom end.  But it sounded so effortless and detailed...especially in the high end. All those years in the box didn't hurt it at all.  The caps were shiny and new with no sign of expansion. I actually wondered if the aging helped it.  

When I took deliver of my Don Sachs Kootenay, I compared them side to side.  And while the Kootenay was the better amp...it was not so much in the high end...the Carver was pulling in a tad more detail there. Let's just say the Carver wasn't at all embarrassed by comparison. And with certain types of music, they sounded almost identical...very weird.

There are also services that will update and bring this gear up to current standards.  Sometimes it's just nice to see old gear working so well in modern times.

Tube technology is very mature and even very old stuff in good condition will be competitive with modern versions.  Also, most classic tube gear can be easily repaired and replacement parts are not hard to find.  

Solid state is a bit different.  That technology is less mature so there are technological changes (e.g., Class D operation) that have come to the fore in the last twenty years.  Also, it can be harder to repair solid state gear because certain parts can become hard to find, such as transistors and integrated circuits.  

Scott - I have a 20 year old Denon and a friend still has a 30 year old Yamaha I gave here and they are still sounding fine.

I just sold my NAIM amp that had to have the power supply caps replaced after 10 years - apparently it’s "a thing" with NAIM amps - nice of them to design in "future maintenance"

So I replaced it with a Bryston that comes with a 20 years warranty.

If your gear is still working and you are happy with it - stop worrying and enjoy the music - it will let you know when its "had enough"

Regards - Steve

I've encountered many 40 to 50-year-old electrolytic caps that test within spec and perform their intended function. Any half-way decent cap will last 20+ years if the associated circuit and its heat dissipation are competent. 

People like to believe they hear dramatic differences when they swap power cables and it's most likely the same phenomenon that occurs when they have gear recapped, i.e. placebo.

If your gear sounds good, it's good.