Old SS amps

Hi Roxy.  I have a 30yo Denon PMA-520 that used to sound great.  I am the original owner, bought it from the original Magnolia HiFi in Seattle back in 1995.  It has sat in climate-controlled storage for the last 18 years or so, unused.  I fired it up a couple of months ago, let it sit for a few days before running a signal through it, then played it and it sounded quite wooly.  I suspect I need to have it re-capped before I pass it on to my daughter.

I don't know if it makes a difference if a device has been used regularly over many years or if it has sat unused for many years.  My gut tells me that sitting unused has more of a detrimental effect on capacitors.  Others more knowledgeable than me might be able to shed some light on that question.

@devinplombier

Hey Devin.  So, I visually inspected it first - no leakage or obvious signs of trouble.  The question is, since I have already plugged it in and tried it, is it too late now to go back and put it on a variac as you suggested.  It was probably 4 months ago that I fired it up after about 18 years in storage.

Question two: If you had two amplifiers of equal age, let's say 30 years old, one had been used almost daily for those 30 years and one had sat for 20 years unused, would one be more likely than the other to need a re-cap?

@devinplombier

Does that mean you do not have an opinion on the specific question?  Also, what would you consider the more important issues?  'Just to be clear, I'm not trying to be antagonistic.  Please don't interpret my questions that way.  I'm just trying to learn. Thanks.