68pete - Do you keep a written log of your equipment use? I have a new tube amplifier and I am in the 20+ hour range and really don't have much of an idea beyond that. Are you just estimating based on an average day or week of listening?
Also, when you say it really opened up, did it sound basically the same for the first 399ish hours and then something changed significanly in a short period of time or was it a gradual change over time?
Also, when you say it really opened up, did it sound basically the same for the first 399ish hours and then something changed significanly in a short period of time or was it a gradual change over time?