I, too have seen 7308, 6dj8, 6922 tubes getting costly.
The really primo ones are expensive, and tough (but not impossible) to get from reputable sources. I remember back when I was doing the Cary SLI-80/ Rogue Tempest shootout, I was having a tough time finding choice 6922 tubes under $100 each- although the ones that I did get my hands on were glorious. Dekay even donated a pair of USN/CEP Amperex 7308s, that I graciously returned to him when the Cary went on its way. What a Guy!!!
I remember from my research that the pinched waist tubes mentioned above are regarded by many as the "best" sounding, although it seems that different circuits would sound different with these tubes- also rumored to be rarer still because they are inherently microphonic for some reason. That price is too high for my blood, although many of our members have an insane amount of disposable income.
I can't imagine ever going that high for a set of line-tubes (maybe for a matched octet of great old 6550-kt88s...)
The really primo ones are expensive, and tough (but not impossible) to get from reputable sources. I remember back when I was doing the Cary SLI-80/ Rogue Tempest shootout, I was having a tough time finding choice 6922 tubes under $100 each- although the ones that I did get my hands on were glorious. Dekay even donated a pair of USN/CEP Amperex 7308s, that I graciously returned to him when the Cary went on its way. What a Guy!!!
I remember from my research that the pinched waist tubes mentioned above are regarded by many as the "best" sounding, although it seems that different circuits would sound different with these tubes- also rumored to be rarer still because they are inherently microphonic for some reason. That price is too high for my blood, although many of our members have an insane amount of disposable income.
I can't imagine ever going that high for a set of line-tubes (maybe for a matched octet of great old 6550-kt88s...)