After 12 hours of burn in of the HP-P1, most of the mid range graininess is gone, but still present. I still can't decide which of the Stepdance or the SR71A is better for the Rev 1. With the Stepdance the sound is very very clean, but with the SR71A there is more body to it. Each time I listen to the Stepdance or ES5 I seem to prefer that amp I am listening to over the other.
But for the mid range graininess, the Fostex DAC is no doubt a considerable step up over the CLAS. The sound is much more natural despite a bit grainy at times, but I think that is more with the recordings than the Fostex itself. The AKM DAC chip, which is widely used in Japanese Bluray players, and also in some very high end Esoteric DAC / CD players (they use a higher end model though), seems to have a sound which I prefer over the CLAS DAC chip. The separation of instruments and the placing of them is much clearer, yet at the same time it retains a bit of warmth which made its sound less "digital". It is like comparing the earlier generations of the Esoteric players with the current generation ones.
Tomorrow, I will spend my listening sessions (lunch hour and after office hours) solely with Filter 2 of the HP-P1, still with the LCD2 Rev 1. I promise I will dedicate my listening sessions to the ES5 and UE18 Pro next week.