op
i don’t know this specific pro-ject phono stage you have...
that been said, i would say, in general, my own experience is rather different than @oldhvymec (who may well be right in what he says referring to your specific unit)
in my experience, the modern russian/chinese/slovak small signal tubes are noticeably inferior in sound quality to even fairly pedestrian old stock equivalents - i am referring to the popular 6dj8, 12ax/u/t7, 5687 families, as well as 6sn7/sl7 octals commonly used in front ends of better tubed hifi gear
to my ear, the modern tubes have good frequency extension and are reliable, but they typically have a little (or more than a little) graininess, and lack the warmth, body, tone, imaging and overall smoothness offered by even modest old stock american ge’s, rca’s sylvania’s tungsol’s (not to mention the european or japanese makes mentioned)