It's true that some amps use MOSFETs that are simply no longer available, period. It's also true that most of Counterpoint's hybrid tube/transistor power amps used these things, too; as a result, if the output stages fail, they can't be repaired in kind. However, as Rwwear says, Mike Elliot will remove the old MOSFET output stages and put in entire new designs that don't use the MOSFETs. The practical result is that the unit is both repaired and upgraded. However, it isn't inexpensive - around $2K is the least it'll cost. For that price you use your existing case and a few parts but get essentially a new amp with a 5-year warrantee from Alta Vista Audio (Elliot's new company).
Counterpoint also made at least one other power amp, notably an OTL model (the SA-4), and this is fully repairable in kind.
Finally, they made all sorts of tube preamps, line stages, phono stages and MC step-up devices, all of which are fully serviceable by Alta Vista. The repairable items are pretty economically feasible. One of my amps was repaired in this way by its previous owner.
Alta Vista also offers upgrades on most Counterpoint gear. In my experience, these are expensive but result in excellent sound, as they basically update really good pieces from the 80s and 90s to current designs. There are limits, but I've been surprised what can be achieved within those limits.
Counterpoint also made at least one other power amp, notably an OTL model (the SA-4), and this is fully repairable in kind.
Finally, they made all sorts of tube preamps, line stages, phono stages and MC step-up devices, all of which are fully serviceable by Alta Vista. The repairable items are pretty economically feasible. One of my amps was repaired in this way by its previous owner.
Alta Vista also offers upgrades on most Counterpoint gear. In my experience, these are expensive but result in excellent sound, as they basically update really good pieces from the 80s and 90s to current designs. There are limits, but I've been surprised what can be achieved within those limits.