On Sat, 13 Feb 2016 15:32:37 -0800 (PST), Phil Allison
wrote:

Woody wrote:



Good idea to power up the amp every so often for a few hours to make
sure the reservoir caps don't dry out, otherwise keep it cool.


** Electro caps lose their electrolyte constantly and the warmer they are the faster it happens. Small caps are the most vulnerable.

When left uncharged for long periods, a chemical reaction takes place called "depolarising" that both reduces the cap's vale and increases its capacitance. If this happens to a reservoir cap,it may overheat and explode when the item is switched on.

Depolarising can be prevented by running the equipment on a regular basis.

More importantly, running equipment for a few hours warms it up and drives out any moisture that has collected.


.... Phil

The equation I use as a rule of thumb for calculating electrolytic
lifetime is Life = L1 *(Vo/Vr)*2^((Tm-(Ta-delta T))/10)

L1 is the specified lifetime. Vo and Vr are the operating and rated
voltages. Tm is the maximum rated temperature, Ta is the local ambient
temp and delta T is the internal rise caused by ripple current.

Applied to a single cap in a single bit of kit, this is essentially
meaningless, but over a few thousand it will give you something close
to the lower 3 Sigma point.

d

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