What makes you build a system around an amplifier?

bdp24,
I can't say what the "cause" was for the "grainy" sound.  The factory rep was proudly describing the preamp/power amp combination driving those speakers.  He did say that he thought the speakers were "unforgiving".  I have found some DACs produce a somewhat "dry" sound, but IMO the speakers sounded "grainy" too reproducing vinyl as well as digital.

How does an amp contribute to imaging? 

Sean:

Really good question! I’m afraid I don’t know of strong research in this area, so I can only guess that in some ways, a good amp does not ruin:

• Crosstalk
  
• Phase
• Amplitude
• Channel matching
  

It may be some amplifiers actually change one or more of these values from the ideal. It has been shown that dips in the 2.4kHz range in speakers can enhance the perceived imaging, so perhaps a very colorful amplifier also plays around in the frequency and time domain.Or perhaps interactions with certain speakers pushes something in the frequency or time domain around just enough. :)

It may be something quite counter-intuitive, like for instance, rolling off the top octave. I don't know enough about imaging science, but I find the idea of Head Related Transfer Functions fascinating, and wonder how they apply to tube electronics.

Hopefully some one will jump in and tell me where the state of the art research is!

Best,

E

Many tube amps do not have a decently flat frequency response under real loads (just look at the Stereophile graphs - they are often horrible). Often their response is tweeked to appeal to the subjective audiophile who thinks his hearing can beat any audio analyzer from the likes of Audio Precision or DScope.
Moreover, image and ’air’ can be quite delusional/artificial properties. Just go to a good concert hall and listen to a symphonic concert. Imaging there is usually far less precise than what you hear at home from your audio gear.

Moreover, image and ’air’ can be quite delusional/artificial properties. Just go to a good concert hall and listen to a symphonic concert. Imaging there is usually far less precise than what you hear at home from your audio gear.

I would hope that at home, we have a much better seat and acoustics.