Lifespan of a quality solid state amplifier?

In 1981; I bought a Hafler DH500(kit), to power the woofers of my biamped system(I was a Hafler dealer, at the time). Gave it to my son, 15 years ago, when I bought a Hafler Trans*nova 9505, to replace it(same purpose). He recently sold it to another friend of ours, and it still functions perfectly. Until now; it NEVER had an easy life!

Many new electrolytic caps are + or - 10-20% and they are usually further out of spec after 10-15 years. They may still work, but they are cheap, why not just replace them. I like Spragues or F&T. If they will fit, I use v-Caps in coupling or input cap locations. They are soincally just superb. I have had a few Illinois electrolyics leak, the brown goo, and replaced those. But, they were 15 years old or more. Jallen

> Filter capacitors have a half life of about 20 years.
> What that means is that in a 20 year period, about
> half of the caps will have failed. This is true of
> transistor and tube amps.

Ralph, I would call this MTBF, or mean time between failures.

http://en.wikipedia.org/wiki/Annualized_failure_rate

"A vendor-quoted MTBF implies that half the drives in a large population will fail within that time of operation."

If in technical school they used half life, I would suggest they either got the term wrong or the definition has now evolved into its current usage as "the period of time it takes for the amount of a substance undergoing decay to decrease by half."

the twenty year half life thing is just wrong and does not apply. No amount of posting will make it right. Half life refers to radioactive material. And it is not mean time between failure. MTBF most often is measured in hours.

Did you know on average caffeine has an 8 hour half life in your body?