It has lately come to my attention that tubes change in a pattern (Cary SLP 09 preamp). Any one notice this:
- New tubes sound great, but with a slight edge
- As the tubes age, the edge goes away
- At some point (in my case just around New Year’s eve/day), the tubes hit a point of perfection – smooth, detailed, perfected soundstage
- Shortly after that period of perfection (lasted about a month), the tubes are sounding noticeably dull – still sound very good (fatter midrange, softer highs), just no magic.
Unlike the PS Audio pre, I don’t know how many hours it took to get to perfection, but I’m thinking this set of tubes are about 1.5 - 2 years old.
I’m also thinking I haven’t swapped the rectifier tube since I’ve owned the preamp (bought it used). Any chance it’s that? I was under the impression the main tubes would last longer.