Lifespan of a quality solid state amplifier?

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Ralph, can you back that up with some references?

Curious where you got 1/2 fail in 20 years.

Even if true, given that the lifetime of a particular cap is inversely proportional to operating voltage and temperature I fail to see how this is useful for predicting the lifetime in any particular piece of equipment.

BTW that is not the definition of half life.

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Just checked 50y.o. HH Scott 222c filter caps and both only lost 16% of capacity.
That makes me think of weather to replace the original or keep it. Replacing the original might require some chassis cutting for the new fitting and near $50 per piece.

Herman, Can you please give us the proper definition of "half life"?

Herman, that is the correct use of 'half life' in this case. This is what they teach you in technical school. I have seen it borne out many times in the last 40 years.

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Marakanetz. capacitance could be OK but ESR and/or leakage too high. It is doubtful a 50 year old electrolytic is still in spec.

Rrog, half life is the time it takes for something to decay or decline by 50%, it is not the time it takes for 50% of a group of objects to fail. For instance; the half life of a discharging capacitor is the length of time it takes for the charge to drop 50%. The half life of an ingested drug is the time it takes the body to eliminate half of it.

http://en.wikipedia.org/wiki/Half-life

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