I don't really know but Cary has made those amps for a long time and I have never heard anyone say they are problematic. Generally speaking some people have trouble with tube amps and other amps by mismatching and over-driving the product. I don't think they are inherently not reliable. Remember some people drive tubes hard even when they have heard a sonic issue and ignore it. That will stress a lot of amps. Keep an eye on bias and don't try to blow them up and you'll be good.
Original Cary 300B Monos Reliability?
Anyone have long-term experience with the original Cary 300B monos (with the single 6SL7 tube)? I'm looking for feedback regarding reliability. I've read that the engineering choices made in the design should have the amps failing on a regular basis, along with eating tubes.
Outside of a few DIY complaint/discussions, I haven't really seen this brought up as an issue.
I'm not concerned about the sound qualities or speaker compatibility as I have heard the combination before. Just looking to see if any of you have experiences to share regarding technical issues. I realize that these amps are now 28 years old, but they are point to point with basic parts. If the chosen values have worked for years, replacing defective caps/resistors should be straightforward.
Thanks for sharing!