Old SS amps

I don’t quite understand cap replacement’s how do you tell when they are bad when I’m still impressed & happy with my systems sound? I’m kind of the mindset that if it works don’t fix it. 

@pjlivengood 

You got it: if the amps work, leave the caps alone.

You may want to have bias current and DC offset checked, however. They tend to drift over time. Elevated bias causes operating temperature to rise, and with it the risk of chronic overheating and thermal damage, which can be quite devastating. As for DC offset, it can potentially damage your speakers, but most amps have protective circuitry that shuts down the outputs before damage occurs.

When I lost a capacitor on my ML 336 the right channel got static that would not go away.  In my experience you will know when one needs to be replaced.

I’ve bought nearly 20 used amps of various vintage, many 20-30 years old by now.  Only two have had sound problems (as opposed to needing new bulbs in meters and that sort of thing): a Levinson 23 which are known to cook themselves to death, and a Classe that still works but has occasional right channel fussiness. 

The rest work great. 

IMHO, buying new vs used says more about the personality of the owner than the reliability of the gear (not saying either is superior).  I have friends that just won’t own used. 

I was given a McIntosh MC2250, it was many years old, I used it trouble free for many more years, until I went back to efficient horn speakers and tube preamp/amp. 

https://www.mcintoshlabs.com/legacy-products/amplifiers/MC2250

Had it checked by McIntosh at a lab day at Harvey’s NYC when I got it, checked perfect, beyond spec, needed one LED replaced; and had it checked/certified by McIntosh factory in Binghamton, NY prior to selling it, needed nothing.

Been using a Sony 3200f since new in the early seventy's.  It was a party amp and quiet listening amp.  Always and the only problem is a burned out "on" lamp.  .  Took it to a McIntosh test and was told by Mac tech it was a "good little amp."  Never serviced but the "on" lamp burned out about 30 years ago.  Now it shares duty with a Decware for fun.  The differences are there but not huge.   A good find would be a bargain.  Good ventilation is essential.