Ray3,

I too have a Denon 3803 and I think you will find that the sub is still active in Pure Direct Stereo mode even if you have your mains set to large and crossover set to LFE only. Try touching your sub driver in this mode to see if it is in the loop. The manual says that this is not the case but I know my sub is on even in Pure Direct with my mains set to small and crossed over at 60Hz.

Stuart

My Home Theater