Replacing p.s. caps in older amps

[whoaru99]

Since I've read that usually it's capacitors that go bad in older amps, I've been contemplating replacing them in my mid-80's Yamahas as preventative maintenance.

As of now, there are no signs of impending failure that I can see. No leakage, no swelling, no discoloration, etc. So, this leads to a few questions.

1. Is this just a make-work project with no real value? I know this is somewhat a matter of opinion, but I am satisfied with the sound of the amps for my HT system.

2. The caps in the amps are Nichicon. The only website where I have found comparable caps (based on voltage and capacitance) listed is on Cornell-Dublier website. Are these "worthy" replacements for the Nichicon's?

3. Would there be any benefit to installing higher capacity caps provided there is room for them and I use wv ratings equal or higher than the OEM's?

I would need the following caps to do the power supplies (this is for the "big" caps in all three amps)

2) 22,000 uf @ 69 wv
4) 47,000 uf @ 45 wv
4) 33,000 uf @ 56 wv

4. There are a number of smaller electrolytic caps throughout the amps. Can I assume that replacement of these would also be in order should I choose to actually do this?

5. Any words of wisdom, or caveats to be mindful of?

Thanks,
Todd

[Kevin P]

If the amp is working properly, the caps in it are still fine. Quality caps can last many years as long as the amp has been used regularly over that time.

In other words, if it ain't broke, don't fix it.

If you do have to replace a cap, replace it with the same capacitance (uf) and at least the same voltage rating. It doesn't hurt to go higher on the voltage, it'll give the cap more breathing room. Don't go higher on the capacitance, the amp was designed for that specific capacitance in the circuit and changing it can adversely affect the performance of the amp.

FWIW, I have some electronics from the mid 80s (and even late 70s) that still work fine with the original caps.