The early Russian tubes, that first were available in the 1990s to the Western World, were godsend to the tube-o-phile community. They were cheap and rugged. An example of this is the 5881WXT which could take the current hungry bias of the Harmon-Kardon Citation V. Even a RCA blackplate of the era would start to glow on the seams. But not these Russian mil-spec tubes.
It's been my belief - shared by some friends too - that Russian tubes have good metallurgy but not the best cathode chemistry. Yes they are rugged, but many of them have the already mentioned issues with the higher frequencies.
As for the Sovtek 12AX7WA, it has a pair of very small coated plates and what I would call a primitive looking spacer that should be made out of mica. The pins ends are sharp but overall construction looks quite good. I plugged it into my Frankenstein EICO ST70, which provides the initial gain before the 6SN7 phase-splitter.
The Sound: Initially I was surprised how much I like the Sovtek. The sound was very transparent and, at first listen, very modern sounding. I was reminded of a really good JFET preamplifier or MOSFET amplifier - big, dynamic and smooth. But, like the aforementioned solid-state gear, lacking in inner detail. The soundstage was also smeared a bit, removing the space around individual instruments and the big front-to-back sound of a vintage Mullard. Dynamics in the upper part of the spectrum became a little rough/forced sounding with the Sovtek.
What I'm really finding - at least so far - is that modern tubes often has a good tonal presentation but lack in inner detail and making a big soundstage. I'm curious to the reason why this is true. Is this linearity or an artificial presentation brought on by - an unknown variable? We shall have to continue and have some vintage comparisons. More later!
