Power Amplifier Longevity

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.

I have a fondness for Class A amps and so paid a fair bit when one of them went south on me, but the particular model I have is quite rare so I didn't even think about not having it serviced. It was over 30 years old. I have two other amps of the same model still going strong, as well as an early Jeff Rowland amp (also 1980s) that still serves in my AV system.

On the current inrush issue, I have an early Belles class A amp that welded the contacts on the switch together due to that. After replacing the switch for the third time, I left it welded together and turn it on and off using a heavy duty power bar!

I have a McIntosh MC207... there 7ch amp that has been in use since 2004....16 years old. It was a dedicated theater amp that for around 7 years did not get used but a few times a year. For the last 2 years it is now in the den system and is used everyday. It still looks and works like new. 

Brian
I have both an Anthem MRX 710 and an Emotiva XPA 5 for sale.  I simply don't do surround media anymore.  If interested let me know.  Both with very low miles and in excellent condition.

And the blind man yelled, "The caps are drying out. The caps are drying out."
Ha ha, Finally a "decent", conversation on the subject.

But again, many seem happy simply to put two cents in.
 And some are worth more!
Heaudio? .....So you've designed electrical equipment and brought it to market?
 It was "UL" approved and then of course, "UL-rated? But alas,"You", did not think to have any IR limiting of any type. Added for any correction or means of protection? Well, since that really doesn't mean anything. Like your words stating that I am wrong about this. Which don't mean much either....since....

 Actually?, The odds are quite high that you "Did", in fact design IR limiting into whatever you are fooling with and bringing to market. "Knowingly OR not! If the electrical device or system followed the NEC, and any other appropriate, local authorities and their addendum, "If any". And you worked utilizing the approved guidelines, materials. Tables and math, governing electrical devices, with the same intent. And the installation and "use of". In the, "Plan, build, use. Glossary and Index." sections were also utilized with an good understanding of the NEC's, "Intent".  All in accordance with the currently, "Adopted", version of the NEC?
Then you did.  Because "We" did. Otherwise it's a bit hard to get anything "UL rated"...….
 Like the guy whom invented sand? I don't believe he designed in all of "sands" insulating properties necessarily on purpose . But since he followed basic "Physics", in the design phase of said, "sand"? 
Sand now, "has", insulative properties.....
 Just sayin....

Heaudio? 
 Also, a bus fuse, "As in ANY bus fuse". Is not IR limiting?
 I guess they are just wasting our time with the fact that they ALL have an precise "IR value", at which point they fail. (Always listed in the device, "properties"), huh?  
Which is why I have used them in designs as "Temp. emergency, "IR" breaks" in switchgear systems during emergencies.
 Also, the reason for many electrical components in a system being de-rated during design is usually for use as a "Safety Factor". Typically calculated as a proportion. These tended to be, "Pre-60's-80's". Always a minimum of 1:4- 1:5. Dependent on the quality of the product line, name and reputation etc. "These days, if used at all"? " I'll notice a percentage in de-rating specs.…."
Many really do not even know or realize. That any such animal ever existed. "The safety factor as it once was". "Kinda like the declared IR value of a fuse. And it's significance in relation to a specific electrical device or system in part OR it's entirety. 

To one, Mr. "JHertzlee", First off. I am not trying to be mean. Nor condescending. And I am simply stating the truth as I see it when I tell you that currently? You are of a mind to be more, "Part of the problem". Than, "Part of the solution". And I truly hope that in a few years you have occasion come back. Reread what you have stated above. And, "Find the light".
 Please, It sounds like your understanding of "transduction", is from a "Tech manual". And it's "Glossary", was very limited in it's scope of understanding. You may want to do a bit of research on that one.
 Also the "Heat" comment? please rethink that. "They are called (Operating temperatures). for good reasons". OR "Should I"? Keep my Hi-End, HiFi, Very expensive components "Inside" of the freezer walk-in. Which I had modified to hold these audio components and still allow the remotes to work for function? Complete with a "Remote Control Repeater". Which means they can just stay at the brisk -22F. in the filtered, Ion rich, cold air, freezer.
Would it not sound better? And last much longer?

"Otherwise, I'm leaving that one alone".  since many would think me cruel if I was to do anything else.

 And, a percentage of your income is attained by, " doing what exactly"? 
Is there perchance a "list", of the parts type. Which would, "Automatically", get changed/replaced by any of the techs working there? "This assumes whomever dropped the amplifier off. Also agreed to pay for a full servicing of the fourteen year-old, Solid State, class A/B, two channel amp with the "Very reputable name", and without, "nary" a scratch on it!. An amp which would bring say, $3800 firm, as it sits on "Audiogon". Very quickly. 
 I would be very interested in your answer, JHertz
   Change All the main, large caps? All the little one's too on the PCB? Interior fusing? Indicator Lamps? A can of WD-40, Then a can of air to blow out the Pots and dust off the PCB? Anything else? Set the Bias if applicable, Give it a listen and then "Unless another problem rears it's ugly head"? Onto the shelf to wait for it's owner? Avg. overall cost?
 I guess "Refurbished" is now the same as "Rebuilt"? or even, "Fully Serviced"?
 And just to ask, To re-flow the avg PCB in the avg. SS amp. How much would it be? if about avg?

I have a pair of monoblock 125 w. Class A/B tube amps with humungous power (electrolytic) storage caps.  They are several decades old and are fully exposed to the air.  The adjacent transformers run so cool that I can nearly wrap my hand around them after hours of use.  

Contrariwise, I have an EAR 890 that after 20 minutes, is nearly boiling hot and touching the transformers can melt one's skin off.  It's a Class A amp with small tubes sealed in the circuit board upside down.   This amp may need new caps in the future.

My prior Audio Research SP14 had a burned out resistor on the center of the circuit board after only 5 years of heavy use.

My McIntosh MC30s still run fine with original caps.  It runs hot as does my modified Dynaco ST70 (new larger storage caps).  

Two Yamaha CR620 receivers began to hum and caps were replaced after 35 years of use for video.

So, some caps last many decades and some probably will do to their high quality and low heat exposure.   Other caps and resistors can burn out rather quickly due to internal circuit board heat.

If you do get an older amp be sure you can find service manuals and schematics for it. Most everything is repairable with some exceptions. But it is much harder without a schematic.