A SE 300B purchased not too long ago is now in use as a permanent amp and not just a casual encounter.
To first experience the 300B, Input Valves were used of a very high quality and also receive wide appraisal. Power Valves selected to be used were classed as temporary or interim while options were considered.
An individual who was not communicated with across a few years came forward with a recommendation. The appraisal given for the recommended 300B was enough for me, as they had been compared to other 300Bs in other Amp's and held up very well. The individual recommending the Valves is a long-term 300B Power Amp user and has owned a selection of designs.
The Brand of 300B was selected, and the introduction of it to the Power Amp was just spectacular. The interim Valves, even though a move away from being Spec' had moments where there was really good impression made. The New Selected Valves, as a comparison, were an unfair match. The interim Valves were destroyed in an instant.
Have the Valves, or Amp improved over time? No.
Has the appreciation of the Valves and Amp increased over time? You Bet.