Dutchman,thanks for your kind words,you too tony.I couldnt agree with you more on your V1 observations.I find this is true with any amp,not just boogies.I have over 100 preamp tubes in my box and from one time to another I love them all for different reasons.NOS and current production.The same tube also acts differently in different circuits. I find that the tonal differences are a little more noticeable in the simpler Fender and Marshall type circuits,that dont have as much preamp over drive as the Mesa's.Another good place to experiment in the MKII's is the 3 & 4 positions for the lead channel.Like you say the quest will never end.