On-board subwoofer amps - limited shelf life ?

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.
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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 sub… 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.