But to me the sweep of the gain knobs (i.e. how much gain is added) is naturally part of the equation, especially in amps where preamp gain plays a big role...And the precise reason the green and blue channels ARE so different.
The tradeoff in cleans with the 100 watt is you have to run the preamp gain really low...you compensate by turning up the post gain, right? right...But, since the preamp gain is pretty low, you still kinda "top out" on the post, to a point.
However, with the 50, you can run the preamp gain a lot higher, and still run the post gain high, too. But because of that, if you switch to the blue channel, it's going to be a LOT louder simply because there is an abundance of preamp gain on that channel. So no matter where the preamp gain is set on the green, the blue will always have more. On any clean channel you have more volume control using pre and post gain controls because of the inherent headroom a clean channel has (less gain stages). On amps with a lot of gain (more gain stages), you are pretty much only relegated to the post gain giving you VOLUME (once the threshold into over drive is reached, which happens REALLY early on the pre gain knob).
Do they stay the same amount of clean at the same volume? For me so far, yes, but I've had no reason to try to crank the clean channel as loud as I can just to compare, nor the desire...But I'd go farther and say that it's "easier" to keep the 50 clean at any volume simply because there isn't an abundance of gain on tap at any point of knob position compared to the 100 watter.
I'll also say that - to me - the 50 watters cleans just plain sound better with the added high end and the lower amount of gain available. You have a lot more "shades of gray" in the sweep to derive varying and subtle amounts of grit across the gains sweep (or conversely, differing amounts of "clean" to suit a variety of definitions of what a nice clean tone is) . With the 100, it's more like 1 clean tone at any point with the preamp gain knob under 10:00...After that, it spills right into the blue channels territory. On the 50, you HAVE to have the clean channels preamp gain DIMED to get it to APPROACH the blue channels gain...Which is why it seems the blue channel is louder or differing in volume.
Make no mistake, both can get loud enough.
I'm not sure how much more I can describe. You'll just have to try it yourself.