There are 2 Rhythm and 2 lead channels; four independant channels, thus the Quad. The Rhythm section is where your ultra-smooth "clean" tube tones are realized. The lead channels are where you would attain the overdrive tones. The E.Q. section of the preamp is defeatable. When you set the four channels you can have four completely different sounds that are all very unique. Engage the E.Q. and tailor it even more. If you want that 400+ tone, it's in there. If you want to expand on that, go ahead the sky is the limit. The quad is the most versatile tube preamp made, period. I do not knock the 400+ though it is my favorite amp of all time.
