After a very long time, I have finally decided to go for the combination of Meier Corda StageDAC and Torpedo parafeed tubeamp.
StageDAC is a DAC with implemented crossfeed which I find working beautifully with HD800 - the soundstage is nearly-perfect now and I would say it's like combining speakers and headphones together (advantages of both). The width is not collapsed, imaging is still there (but image-heads could maybe find it a little bit worse), separation as well... But there is DEPTH which in my opinion expands and completes the experience. In comparison with several software versions of crossfeed, this one is definitely superior - a lot more natural and functional since it really expands the depth, not only "fakes" it by adding reverb or somehow collapsing the soundstage's width. In comparison with Daccord, there are significantly more options of customisations the crossfeed which I definitely find preferable.
Another reason why I purchased StageDAC, is the possibility to influence the sound by setting Pulse response and Oversampling. There are several combinations of both, all sounding a little little little bit different. One can use it for two primary purposes - to choose what sounds best for him (like mimic NOS DACs or vinyl sound for example, possible!), and to shelve down treble if needed (sort of hardware-based equalizer because different settings offer different response above 2khz = highs). Daccord unfortunately doesn't feature this anymore =/ Nevermind, very nice but it's not all! There is a Tonal Balance switch which I find VERY important and which can also be used in two ways - to perfect the FR after applying crossfeed (by emphasising bass and mids = frequencies up to 2khz), and as a very potent bass eq. In the highest position, the bass hits very hard with HD800 (in expense of collapsed separation (gets strangely near to LCD-2!), therefore I use the middle position which is very life-like).
And there is the amp, Torpedo... It was a tough decision but after a lot of reading and asking I decide to go for this amp with parafeed technology which appealed more to me than for example Bottlehead crack or Earmax Pro. In short, I liked the appearance and practicality way more, a presence of impedance switch to work with various headphones is pretty much welcome, 6 different matched sets of tubes which I got for free as well, of course!
But, the primary thing was the parafeed technology which should work with different headphones (and not only with high-impedance ones like with Crack or Earmax), and shouldn't put emphasis or decreasing any frequencies while still working well in mitigating harshness which could be present with certain setups (near-zero output impedance SS - high impedance headphones). Also, I can have my headphones plugged in all the time (on/off procedure is no problem here), that's how it should be in my opinion! In the end, tubes also offer another way how to very slightly influence the final sound, another sort of hardware-based equalizer.
I wanted to stay reasonable on budget and find a very versatile setup with many options in order to not get bored with my chain sounding the same all the time, but still stay "bitperfect" (not a fan of software DSP anymore since I use Jplay but that's another story). I must say I was playing pretty much safe and it was a good decision. This is my final rig for several years, until something significantly interesting appears on the market (like great headphones with implemented crossfeed or cheaper/easier-to-go version of Realiser). I am already enjoying the sound and versatility and feel that my money were spent well. The synergy with HD800 is sublime since there are so many options how to get the sound right that it's almost impossible to say the opposite :-) It's definitely enough for me, I feel zero needs to spend more... Now, let's get back to music, to what counts in the end!
Edited by RustA - 3/30/13 at 2:31pm