Personally, I think the preamp of the Rectifier line is the worst part of it. I am in firm belief that all the magic happens in the power amp section. For example, most people do not use the Red (or Modern) mode for the gain channel. I phase it that way because it could be Ch-2 or Ch-3, depending on if it was an early Rectifier or not.
To me, when they offered the Preamp and Power Amp separately, they gave the option for the awesome section (power) and the crap section (pre). I have gone through two 2:100s and my current is a permanent addition to my collection. Every preamp I have paired it with sounds amazing, even with Modern engaged. It sounds sweet, responsive, tight, and musical and when you kick in the Red, it just gets a little meaner and a whole lot more depth gets added, but not boomy like a typical Rectifier head.
This is just my opinion in the experience I have had. I will say though, way back before I really had "my" sound in my earlier years of playing, I had a 2-Ch Triple Rectifier that I put a Mercury Magnetics output transformer in. That thing sounded amazing, regardless of volume and on any mode. I kind of wish I still had that one, but oh well. I have no idea what revision it was either because at that time, I knew nothing of the technical details. I really think that the one I had was one of those ones that just had some kind of "mojo," as they say.