In recent weeks and months, I've noticed a certain oddness to sibilant sounds, almost like when you think a radio is tuned in properly and then the "s" sounds make you realise it's not right on the station. Okay, it's milder than that, and until this evening has been in the "am I imagining this?" folder, but I'm now sure the effect is real. A quick gander at the valves revealed this:
and, interestingly, the same thing could be seen on the same valve on both monos, although much less so on the left.
So, is this a busted valve? I replaced the power valves when I bought the monos, but never replaced the smaller, input valves, and for all I know they're originals and have many tens of thousands of miles on them. The valve pictured is an EF184, which I know absolutely nothing about. I'd need 4 of them per amp, and if I was replacing them I'd probably replace the two 6922s per side as well. I'm reluctant to get into tube madness, so I'd just be looking for something good, robust, and not breathed on by ancient dragons of Atlantis.
Any thoughts?
