Cap life span?

>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.

>Tntate (Threads | Answers | This Thread)

>Cap life span?
On a tight budget. Looking at older amps and need to know if capacitors have a set lifespan. How would I know if they need replacing?

Get some big power resistors which can be wired in parallel to produce an 8 Ohm load with sufficient wattage and validate that your amplifiers aren't clipping at their rated output power.

Or buy an inexpensive ESR meter and validate

http://www.amazon.com/Anatek-Corporation-blueesrassy-Blue-Fully-assembled/dp/B005NI4WE4

In most cases they won't have been run hot enough for long enough to cause damage.

I guess I've replaced WAY too many electrolytics, in power amps, Leslies, Tubed Organs and speaker systems, pro and home(for myself as well as customers), to buy into some the above statements.

The main reason to replace them is doing so may well result in an incidental upgrade/or deliberate one. Typically included in a complete overhaul. Well worth the average cost of around $400.00 for an amp.

Bottom line is don't buy old gear unless you are prepared to replace all coupling caps, wire, lytics, tube sockets and tubes. This is quite common. Jallen