I can only speak for my experience, have atmasphere ma-1 and mp-3, rolling 6sn7 and similar on pre amp discovered that the cv181-t black treasure on the pre amp sounded amazingly good compared to stock and nos chrome domes, well that's not the end of the story. When NOS high quality and conductannce used these were better than the black treasures tubes, not all NOS are created equal that's my conclusion.
When Sylvanias were rolled into the ma-1 and entire different sound developed, more e coherently sounded was implemented
Very very happy with my amps and pre
When Sylvanias were rolled into the ma-1 and entire different sound developed, more e coherently sounded was implemented
Very very happy with my amps and pre