I thought I'd call Cary however I have to wait until Monday. In the past they have not been a great deal of help regarding other tubes. They have suggested to me, to stay with the tubes that the equipment comes with.
In the case of my 2A3 tubes, I have improved the sound greatly by using different 2A3 tubes.
In the case of my 2A3 tubes, I have improved the sound greatly by using different 2A3 tubes.