Audio Research D240 mkll vs Adcom GFA-555

I bought an Adcom 555 MKII, along with a GFP-565 preamp, brand new back in the 1980s and used them with Magnepans for about 5 years. I never had it modified and what teo_audio stated in his post about graininess makes a lot of sense to me. I subsequently used McCormack and Aragon high current amps over the next 10 years and, in my opinion, they both sounded very similar to each other and both were significant upgrades over the unmodified Adcom.
Over the past 5+ years I’ve used class D amps, stereo Class D Audio and Emerald Physics units and currently a pair of D-Sonic monoblock amps. All of these newer class D amps outperform all of the large, heavy class AB amps I’ve previously used by a wide margin.  They're better in every area I care about: low distortion, high power, high signal to noise ratio, powerful and realistic dynamics, solid and stable imaging, highly detailed and possessing an overall accuracy, smoothness and naturalness. 
If you’re looking for a significant upgrade, I’d suggest trying out at least one high quality class D amp.


Tim

clearthink:" You must have employed the use of some really mid-fi or mass market class AB amplifiers in your Music Reproduction System if that was the result and consequence you experienced when substituting Class D amplifiers for them in you're system..."

Hello clearthink,

     As I stated, I've used 3 high current class AB amps in my system thus far, an Adcom, McCormack and an Aragon.  I believe most members would consider all 3 of theses as at least good quality class AB amps with the possible exception of the unmodified Adcom being considered mid-fi and mass market. 
     I think a very large and expensive Pass Labs AB amp would be required for a class AB amp to outperform my current D-Sonic monoblocks.  I've auditioned Parasound and Bryston high current amps already and discovered those will not.
     Sure, an even larger, hotter and much more expensive class A amp may sound marginally better.  But my D-Sonic monos are smaller, run cooler, were $2,100/pair, are paid for, consume orders of magnitude less electricity to operate and I perceive their sound quality performance  as exceptionally good.
     Thank you but I don't consider your suggestion of switching to class A amplification as clearly thought through. 
     However, I suggest you consider auditioning a good quality class D amp in your system to broaden your audio knowledge and experience.

Tim