amplifier longevity

Too many factors involved. The design, the operating mode (Class A vs AB), parts quality. That also doesn't assume catastrophic tube failure, or shorting the speaker terminals of your SS amps.

 Under normal use, no reason either can't be completely reliable.

The exception to all of this is Class D. I am seeing an up tick in Class D failures of amps that are only 3-5 years old. Some have even become non-repairable due to obsolete parts or boards.

Depends on build quality does not matter tubes or ss..

Because I am a compulsive spender I tend not to keep equipment as long as I should. 

That being said the oldest amp I owned was a set of Manley Neo Classic 250s. I bought them used when they were 7 years old. 

I traded them in for a set of Class D monoblocks 3 years later because I couldn't stand the heat and the tube maintenance. 

At 10 years old they ran like champions and had not one issue.  

I have a Rogue Audio Sphinx in use for the last year with no reliability issues.  But you would expect that after a year.

I have two Prima Luna tube amps in use, a Prologue Two Integrated and a Prologue Five Power Amp, with absolutely zero issues since 2005.  These amps are so over built I don't expect issues ever.  

I have two Musical Fidelity SS CD players, CD PRE 24 and A3.2, with zero issues since 2003.  MF has changed ownership and places of manufacture since, so no idea about current products.

I have an Outlaw RR2150 receiver with zero issues since 2005.

I attribute that run of good luck to not overdriving the equipment and choosing good companies in the first place.

I had a NAD C320BEE integrated that gave up the ghost after a 10 year run.  Also, a Class D Audio power amp that kept breaking down and I gave up on after a year.

I would expect Luxman to last a good long while, given what they charge.  I put them in the same league as McIntosh.

Rich 

I’m a die hard Mac guy, but Luxman is a super nice all in one unit. Tubes Vs SS it’s alway maintenance. More on a valve unit, but not much more. I was raised on valves, SS was added not the other way around. I like everything pretty much.

Class A, A/B. SS or valve. Class Ds with buffer boards and rollable OpAmps, without buffer boards, ZERO feed back, a ton of feed back, adjustable feed back.

Just make it work. I’ll make my part work.. I won’t hook it up backwards. :-)

Merry Christmas

Regards