Well, I'll tell you, the Crack with the HD-800s I heard at RMAF was all stock parts (except for the experimental high-current modificationn) and it absolutely blew me away. That's what I mean when I say that I honestly don't think you're going to hear much difference, if any by upgrading the current set resisstor on the C4S board. Yes, your sources and cans are all right up there but so was the Doc's tape rig and DAC with the HD-800s.
As a result, there is very little other than coupling caps, OCC airlock copper wire, tube sockets, Neutrik pro jack, pot and coupling caps that I plan to change Hmmm, well, ok, that's a fair bit, but most of those things are for better long term reliability more than anything and I certainly wouldn't hesitate to build a second pretty much stock as well.
I guess I'll see if it was worth it in the end, but it's going to have to be utterly amazing to beat what I heard at the show.
-- Jim
Jim Rebman -- recovering audiophile
Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).
s.e.x. 2.1 under construction. Want list: Stereomour II
All ICs homemade (speaker and power next)