and they turned my mark III into a fire breathing dragon! I cannot believe the difference they made compared to the mesa tubes that were in it. I slapped them in V1 and V3 and the cleans seems more clear and full but not as chimey as before. Really liquid like. THe lead channel, oh the lead channel, is now a monster. More low end, more clarity, punchier, and huge chunk. When I first started it back up and was playing, I thought wow this is great, then i realized that i didnt have pull deep or pull shift pulled like i normally do. OMG! Pull deep is now way more responsive. I hit a muted E chord and I thought a plane flew by creating a sonic boom...lol! Needless to say, I am smiling ear to ear. Thanks to those that recommended the RFTs, as they truly made this a better amp than what it already was.