You are correct Gil, as someone cleared up a couple posts back. I thought it was weird too, but that was what I had read in the post, so I felt compelled to verify it.
Kent, I was wondering if there something like phase cancellation going on. As I turned up the volume on one channel, there is a point where the volume dips slightly. I suspect that this was the point where both preamps had nearly equal volume, and consequently, maximum phase cancellation. From my limited efforts in this vein, I observed that this effect is pretty well masked when the volumes of the two channels vary by a large enough amount. So even though there was some cancellation, the sound seemed more beefy than either channel on its own (I wouldn't necessarily say more bass, just thicker somehow).
