Cap life span?

If you look at the datasheets of aluminum electrolytic caps; you'll find that their expected life spans are noted in hours, at a certain temperature. Some datasheets even list an expected shelf-life. These sites each mention different ways caps age/lose their values: ( http://www.elna.co.jp/en/capacitor/alumi/trust/index.html ) ( http://chemi-con.com/u7002/life.php ) Some good info here: ( http://www.hans-egebo.dk/Tutorial/electrolytic_capacitors.htm ) If the amp is approaching the 20 year mark: A cap change is a good preventive maintenance measure, and you'll probably notice improved performance in the system's bass & overall dynamics.

If leaking then replace. Sometimes a new one is bad. If all is working and specs fine leave it alone. I like to change mine when I get a new tube amp, but this an ocd indulgence rather than a sonic necessity. Jallen

When talk of replacing electrolytic caps comes up on this and other forums. Most people are concerned with the larger can style caps found in amps and preamps. Overlooked are the dozens of small value electrolytic caps such as those found in cd players, remote controls, secondary power supplies etc etc. Looking at a spare cd transport I have in storage (that is 20 yrs old) I see about 30 small value electrolytic can style caps soldered to the circuit board. Do I worry about these caps being dried up? No, and I dont worry about the large caps in my 20yr old amp, 30+yr old receiver and many other pieces of equipment either. Never had a Electrolytic cap go bad on me. However, I never let my equipment sit dormant for any prolonged lenght of time. Including hooking up the spare transport and running it occasionally. Which I think is probably a key factor in prolonging the life of electrolytic caps and avoiding failure.

08-06-12: Rodman99999
>If you look at the datasheets of aluminum electrolytic caps; you'll find that their expected life spans are noted in hours, at a certain temperature.

Right. That's usually 85 degrees C but can be 105 degrees C which is hotter than boiling water.

Life doubles with each 10 degrees C lower. At a pleasant 20 degree C room temperature a "1000 hour" capacitor is good for 90,000 hours or 10 years of continuous service. 2000 hours is more typical which nets 20 years.

People who turn their equipment off when not listening and will find their electrolytic capacitors much longer lived. Averaging 8 hours a day they might last longer than you do.

>08-06-12: Reb1208
>When talk of replacing electrolytic caps comes up on this and other forums. Most people are concerned with the larger can style caps found in amps and preamps.

Those are generally (output capacitors on an OTL tube amp would be an exception) the only ones which see significant ripple currents which make them hot inside and therefore likely to fail.

>Overlooked are the dozens of small value electrolytic caps such as those found in cd players, remote controls, secondary power supplies etc etc.

For electronics only powered up where you're listening to them with reasonable ventilation I'd expect those to outlive their first owner.

>Never had a Electrolytic cap go bad on me.

My Lexicon home theater preamp became inoperable due to a failed electrolytic capacitor in the switching power supply which AFAIK was always powered up.

I've replaced electrolytics in my pinball machines where low power supply voltages resulted from the excessive ESR that developed - they really don't like the heat from all the miniature light bulbs in the back boxes.