Thank you for your patience and explaining it clearly. I only have a d800+, but now i understand much more about the tt800 and how it was designed to operate in a specific way.The signal flow and switching diagram shows everything. Both channels are active all the time, the effects sends are pre channel switching and the post eq DI is post channel switching. This is discussed in the manual. It’s s asking been discussed how summing the two channels was never the intent due to serious phase differences between the two channels from the very different voicings.