I own the ultimate versions of Rons' 300b DRD, and 45 DRD mono blocks. The 45 mono blocks took a very long time to break in completely. they always sounded really good from the start for many months, then one day as Emeril says "BAM!." It opened up and it was like listening to different amplifier. The sound really opened up and it became almost 3-d with the voices and the sound stage got much w-i-d-e-r. These amps do not look nearly as good in pictures as they do up close in person. I like Cunningham 245 tubes the best in my 45 DRD amps. I want to try a pair of WE 300b when I have the loot to spend for those $$$$ tubes. Good luck with your amp! John