Dusty:
The other option is, "they don't scale" but sound good with everything. To me, the question "does it scale" assumes that there is some combination in which they don't sound good.
Despite almost single-handedly dissolving Head-Case, I have no real power. I have a feeling they'll take away my plastic shovel now that they know I have one
My $0.02. I think the you'd better be served by investing in a source, rather an amp. From what I've seen, IEMs do indeed scale up to a great source, but I'm not sure at this point I can make that same argument for headphone amp.
The worst thing about LTSpice is the schematic capture. Can your CAD program export a netlist? It might be easier to work with it in text form (this is what I do) and bypass the schematic capture program. If it helps, I can upload you a high voltage regulator circuit that I put together (and subsequently made boards, so yeah it works) to play with.
We have released DipTrace for Mac OS X (version 2.1.0.7).
http://www.diptrace.com/downloads/DipTrace.dmg (128 Mb)
This is Freeware (300 pin) edition, however it can be converted to any
edition or trial with your registration key. It also requires right
mouse button as this is originally Windows application.
In my opinion, the 840c has sort of an artificial resolution or detail. It doesn't sound right, almost like it's trying too hard to be resolving... hard to say, but it's not a realistic detail at all. So, I couldn't really call that a strength... imaging I could agree with.