Audio Research D240 mkll vs Adcom GFA-555

noble100"All of these newer class D amps outperform all of the large, heavy class AB amps I’ve previously used"

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 but the important thing is that you made some real, genuine, audible improvements and I can only suggest, recommend, and encourage you to audition some superior amplifiers within the same Music Reproduction System such as properly designed, specified, manufactured and installed Class A amplifiers. Good luck to you there is more out there don't stop now!

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

noble100" 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."

Those are not only mass market midfi amplifiers they are so old as to be nearly laughable they would likely need substantial service and parts replacements because of the age of the components contained there in.

Having owned multiple models of ARC solid state and Adcom amps through the years, I am certain the ARC would sound superior to the Adcom.  I would advise calling ARC, however, and verifying if the D240 is still serviceable (if it ever broke down). I like ARC gear, but some of the older solid state stuff has components they have obsoleted and cannot be serviced. I would advise making sure the D240 isn't one of them.

Thank you all for your thoughtful input. Everyone had great points and all were taken into consideration. The conclusion was I decided to take a much larger leap and purchase a Pass Labs XA-30.5 from someone here on AG (much to Erik_Squires chagrin I think). But I've enjoyed the modded Adcom and have been wanting to hear Nelson Pass's recent work and this was an opportunity to make that move. It's probably the only Pass amp I could ever afford but the reviews have been nothing but stellar. So thank you all again.