Power Amplifier Longevity

I can only speak for myself. I built a Hafler 500 in 1975-76--can't remember that far back!--and use it today.

It was in the shop recently as I was able to score an Audio Research preamp, finally!, and wanted to be sure the Hafler was OK.  

Tech said that the bias was WAY OFF for some reason, but once he adjusted it, everything measured within spec, and it sounds just fine (for a non-tube amp), old "caps" and all.

I do know that in my Sunn guitar amp they replaced the caps and possibly a few other parts, but these amps are used for playing instruments and taken on the road, so not surprised that some parts eventually fail or no longer perform in spec.

I am looking for an Audio Research tube amp to go with my preamp, and when I find one, it being tube and running much warmer than most solid state amps, I will have it checked out (can't afford a new one) for performance before putting it into the system.  Also need an EC2 or EC3 so I can keep the Hafler on the bottom end of my Maggies, so will have to have it checked as well.  

Old stuff is old; have it checked out before incorporating into your system and you should be fine.

Will something fail eventually?  Of course.  Back in the day, we got in a number of DOA items, so new is no guarantee either.

Cheers!

My 7 pieces of 30-40 year old Bryston and Audire amps and preamps are doing great.  So are my 40 plus year old turntables and tuners. I did get Bryston to rehab the preamp.  It had a badly frayed power cord, and a very slight hum when turning up the volume enough to use a low output  M/C cartridge (because a house guest left my battery powered Audire head amp on and put new batteries in it backwards. It has finally been replaced with another one I ran into.   The only other issues I have had during this time were caused by me and my friend Johnny Walker.  Another amp and preamp are dead because of my ineptitude, not from material or design flaws..

I have a pair of Mac 1.2 KW amps any idea how long these will last

@jollygreenaudiophile2Talk about misinformation, you are full of it. Since when in the electronics world is heat a friend of ANY electronics?? Since NEVER. What are you talking about "transducers" in an amp for? Are you converting liquid flow into a 4-20 ma signal or pressure into a 4-20? maybe you are using your "transducers" to convert temperature into a 4-20 or a 1-5V signal. Give us a break. I refurb. vintage amps as a second income, caps don't just fail cus they "burst". most old caps are fine in a vintage amp, but a lot are way out of spec, some are even open with zero capactiance. This is why its standard to do the entire amp with new electrolytic caps to avoid any trouble later. 
To the guy who thinks using an amp is too hard on the caps, um... the opposite is true, show me an old amp that's been sitting in the closet for 20 years & how those caps are holding up. Old caps need to have voltage applied now & then, like reforming. Standard procedure where I work is to reform the large caps in a VFD every 3 years if they aren't being used or sold. I also use caps that are at least 10v higher in rating, using the 105 deg. for those in power section or near heat sinks.
Yea so I'm one of those guys who repalces a lot of electrolytic caps, but I work mostly on stuff that is from the 70s & early 80s, the good stuff. Both my Mcintosh power amps, one a MC2100 is still a daily driver since high school, are still running strong, so are all 4 of my Kenwood L-O7M's
So go buy some new equipment, if that is what you are into, spend 10K or more on a 7.1 channel for your TV, but its just a TV, not a hi fidelity 2 channel stereo.