A while back I remember reading that the 6505+/5150II has a tube dedicated to the green channel and that replacing it with a 12AU7 or 12AT7 can greatly improve the clean sound. I've done a little searching but can't find the thread again so I was wandering if any of you guys know the details of this? Specifically, which tube needs replacing (i.e V1/V2 etc...) and which variation of the 12AX7 will yield the best results.
