Power Amplifier Longevity

Quoted from United Chemicon:

(a) Operating Voltage

When in service at voltages equal to or below the rated value, the life of electrolytic capacitors is affected less by applied voltage than by operating temperature. Figures 7, 8 and 9 show life test results with various reduced voltages applied. The curves show that the life of the capacitor has not been significantly increased by a reduction in voltage. This is due to the use of proper forming voltages to minimize gas generation and leakage current. From this we can say that when capacitors are used at or below their rated voltage, the acceleration factor AV is equal to 1.

My point in choosing a capacitor to have a max voltage higher than normal is so that it handles the voltage spikes that are likely to happen.  If the AC mains was perfect, it would not be a problem.  But if any AC machinery or any kind of inductive load is running near the outlet to which your device is connected, if the devices do not have excellent filters, they will cause spikes on the AC line when powered off.  So, a cap with a higher voltage rating will favor better than one which does not.

I am not trying to increase the life of the capacitor by choosing a higher rating.  I am making it more resilient to possible spikes over the long term.  That is the essence of my argument.

I can only speak for myself. I built a Hafler 500 in 1975-76--can't remember that far back!--and use it today.

It was in the shop recently as I was able to score an Audio Research preamp, finally!, and wanted to be sure the Hafler was OK.  

Tech said that the bias was WAY OFF for some reason, but once he adjusted it, everything measured within spec, and it sounds just fine (for a non-tube amp), old "caps" and all.

I do know that in my Sunn guitar amp they replaced the caps and possibly a few other parts, but these amps are used for playing instruments and taken on the road, so not surprised that some parts eventually fail or no longer perform in spec.

I am looking for an Audio Research tube amp to go with my preamp, and when I find one, it being tube and running much warmer than most solid state amps, I will have it checked out (can't afford a new one) for performance before putting it into the system.  Also need an EC2 or EC3 so I can keep the Hafler on the bottom end of my Maggies, so will have to have it checked as well.  

Old stuff is old; have it checked out before incorporating into your system and you should be fine.

Will something fail eventually?  Of course.  Back in the day, we got in a number of DOA items, so new is no guarantee either.

Cheers!

My 7 pieces of 30-40 year old Bryston and Audire amps and preamps are doing great.  So are my 40 plus year old turntables and tuners. I did get Bryston to rehab the preamp.  It had a badly frayed power cord, and a very slight hum when turning up the volume enough to use a low output  M/C cartridge (because a house guest left my battery powered Audire head amp on and put new batteries in it backwards. It has finally been replaced with another one I ran into.   The only other issues I have had during this time were caused by me and my friend Johnny Walker.  Another amp and preamp are dead because of my ineptitude, not from material or design flaws..