[GnuB]

I thought I would give a quick update.  I modded the HD555's according to the instructions (removed the foam) and notice a slight improvement in soundstage and perhaps more bottom end.  I also put the AD697 in the headphone amp socket Aune, and again, believe it to be a slight improvement in soundstage and midrange smoothness over the stock op-amp so by now it should be as good as it gets with this particular setup and HP.
 
The problem is that I went back to listening to the Harman Kardon HD400 -> Parasound HP 750II -> Crown Straight Line One combo doing some comparisons using the Allison Krause "Forget About It" cd.   The HP out of this setup is much fuller, warmer, more detailed, sweeter, less analytic and down-right more enjoyable than what I am hearing out of the Aune.  Go figure...  I guess I was expecting to be blown away by the new technology specifically designed for headphone use.  It is not that the Aune is all that bad, in fact I am pretty impressed that such good sound can come out of a device using chips the size of a tic-tac and I plan to keep on using it, but it may get relegated to use as a DAC or as my office HP amp.  Anyhoo, the schooling goes on.  Next week I should get to listen to the HD580's that are on the way.

 

[Currawong]

That's par for the course for low-end gear. Mostly it's choose-your-flavour with different OPAMPs.

 

[GnuB]

 
Quote:

  That's par for the course for low-end gear. 

 
So where you consider that the separation between Low-End gear and High-End gear begins and what is the distinguishing factor?   Is it about discrete circuitry or is it all about $ spent?  In an earlier post you recommended the NFB-11.  It does have discrete circuitry and was only slightly higher in price than the Aune at the time.  Does that unit fit into the High-End category?  
 
So far I have $170 in the Aune and $75 in the HD555s and the combination sounds reasonably good to me.  I will have another $175 in a set of HD580s with HD600 grills and HD650 cables that are on their way.  At this point my wallet feels some pain but is not suffering badly but from here on it may be a case of diminishing returns.  Would one have to spend twice as much to achieve a 10% improvement or is it even quantifiable?
 
I already had the CD player, pre-amp and power-amp laying around and that combo sounds reasonably good to me also and maybe a tick above the Aune.  It is all vintage discrete equipment, and at the time was probably pretty pricey.  I guess it is the standard I will go by.  If I can't determine that something else will be significantly better at a reasonable cost then I probably will just enjoy what I have.
 
BTW, I guess you consider the HD580s to be in the High-End gear category since you recommended them.  I am not trying to be contentious here, just trying to understand.  That way I can make more informed purchase decisions.
 
 
EDIT: I guess it is time I dug into the High-End forum and find out what it is all about.