electrolytic capacitors are notorious for failure - they are made with a paste that is mildly corrosive - at some point manfs. started putting buffering agents in them - not sure when but it was AFTER the mid-1980s
Besides that, they must be conditioned for proper function; they will lose that if not used for some time
they are likely to have been used in both power amp and pre-amp
some types of caps can lose capacitance just from aging - I don't recall which types and don't know if they were used in your equipment, but electrolytics definitely change in C as the electrolyte evaporates
I suppose changing out capacitors after some years needs to be considered standard maintenance, like changing the brake fluid on a car.
** the above is all standard electronics engineering practice and NOT subjective tweeker fru-fru **
So...
I suggest listening to some equipment from nad, Cambridge Audio, Rotel or similar well-engineered products that can be returned in 30 days or so if you do not like them.
Select some revealing program material - female vocal, snare drums, deep bass, piano, etc. and try to set up both A/B switching on short 1 minute or 30 s. segments as well as extended periods of listening.
Besides that, they must be conditioned for proper function; they will lose that if not used for some time
they are likely to have been used in both power amp and pre-amp
some types of caps can lose capacitance just from aging - I don't recall which types and don't know if they were used in your equipment, but electrolytics definitely change in C as the electrolyte evaporates
I suppose changing out capacitors after some years needs to be considered standard maintenance, like changing the brake fluid on a car.
** the above is all standard electronics engineering practice and NOT subjective tweeker fru-fru **
So...
I suggest listening to some equipment from nad, Cambridge Audio, Rotel or similar well-engineered products that can be returned in 30 days or so if you do not like them.
Select some revealing program material - female vocal, snare drums, deep bass, piano, etc. and try to set up both A/B switching on short 1 minute or 30 s. segments as well as extended periods of listening.