On-board subwoofer amps - limited shelf life ?

Both me and my hi-fi godfather purchased subwoofers for 2-channel systems in 2000, I got a PSB Subsonic 5, he got a Monitor Audio FB 210 for his Monitor Audio speakers.

Both our subwoofers failed this year, mine a victim of a power surge, his blown up by his teenager sons.

Are subwoofer amps worth replacing/difficult to replace? Do we have to go up to the REL/Velodyne level to get a longer lasting sub? Anybody have good things to say about Von Schweikerts, James, or Supercubes? Thanks ahead of time.
I think the problem lies with stand bye modes on afordable sub plate amplifiers many of my sub amps run hot even in stand bye, since amps on pretty much always and sub amplifiers in general dont seem to have enofe heat sink area they heat up causing early amp failers.When you look at prices that many subwoofers go for its no wonder they dont use high quality amplifiers.I have seen posts about REL amp problems but so far no velodynes.As far as replacement amps if you can find a plate amplifier that fits cut out on back of your sub you can change them out with little trouble.Madisound or parts express stock sub plate amps.
My speakers have active amplification and are 12 years old. My subwoofer has active amplification (1000 watts) and is 9 years old. Both work perfectly with never a problem.

On the other hand, I had a 240 Watt top of the line Sony power amp fail after 6 years and an HDTV top of the line Sony TV fail after 6 years.

I don't think you can generalize, however, I have stopped buying Sony products.
Why are you blaming the amps? They were both subject to abuse.
As far as the PSB subs..this is a real common thing, my neighbors burnt out.. they don't have any external heat sinking and he had his inside a cabinet (WAF).

I've owned 2 Velodynes and never had problems, but then again they were the higher end series.

Plate amps are typically cheap...and the vibrations kill the cheap amps.. but the PSB subwoofers don't have any external heatsinks and they are small subwoofers typically so they get overdriven, and they don't have any protection like Velodyne Servo Subs do...

If you don't have a 15" sub and you watch movies it's working too hard! Plus not many people calibrate their subs with AVIA or digital essentials and a sound pressure meter, or limit their subs outputs with a high end surround processor like my Meridian.

Another option is to go with some SVS subs and get a Crown K1 or K2 external amplifier .. not the tightest subs but bang for the boom..

3rd rule of subwoofers is if you want them small you have to pay to make them loud! (bigger amps, 2-3" excurision drivers and huge magnets to handle the large 1500-3000 watt Class D amps..)
Cheap replacement amps: mcmelctronics.com or partsexpress.com
Shadorne: "I don't think you can generalize, however, I have stopped buying Sony products."

Me too after THREE 23" Sony monitors died within about 5 months. I replaced them with a quite-inexpensive Princeton 20" 1.6 monitor at Costco and am very happy with it. I consider Sony to be the Microsoft-type bully of the consumer-electronics world and avoid their stuff including Blu-ray hi-def-video discs.
Being that there is a ton of internal vibration, and heat generated in a more sealed enclosure due to driving such low frequencies in a subÂ… its not that surprising.. But there are better amps that could rectify this I am sure, however most are pretty cheap, newer digital designs probably fair better in the long run as well, they draw less power, next to Zero heat, and the components being much less are probably less sensitive than the standard A-B type designed boards.     
undertow the sub amps I have are digital and still run hot as all heck. I have never seen a sub amp fail due to vibration but I have seen many fail due to heat.
Johnk, What Digitals are those? Huh, I have had, Bash, Crown, Keiga... All are as cold as the metal they are mounted too even driven for hours at a time.. I have a Digital receiver which is considered a Hybrid for my HT system, and it runs a bit warm, but not too bad, And I don't think that is due to the Digital amps inside, but the Preamp section... But never had a straight digital have any temp at all over room temp, so that is strange and a new one to me..
The dig plate amp that runs hot is a keiga. I have had 6 now all the 1000 watt run hot even on stand by, madisound had early units fail keiga made a few changes, but I could cook a egg on it;) When its running not so hot, but on stand by heat builds so I just turn it off and on when needed.I have had good luck with hypex plates still enjoy the big keigas just worry how long they will last.
Huh, yeah I had the Keiga 1000 watter and it was never even running warm... interesting, but of course I had it probably going on 5 years ago now, so the changes you state might be what is different, I know mine was ICE modules, maybe they are using a different brand now.