Yamaha A-s2100 vs A-s1100

Interested in the differences between these two amps, and also the quality of the built in headphone amp. Thanks
Not sure about those particular models but I have had the A-S500 (which I gave to a friend) and currently have the A-S2000 and it is superb.  I don't use it for my headphone amp so I can't comment on it but for driving speakers and the build quality I can't say enough.  I also have the CD-S1000 (bought used) and it is more musical than many of my dacs.  I feel like I need to unbox my cds that are in storage and listen to them again instead of wav/flac files played through several of my dacs.  
I use the A-S500 with my computer and am very pleased with it
From what I can see, the A-S2100 has (4) 22000 microfarads power caps and a fully balanced design while the A-S1100 has (4) 18000 microfarads power caps and is unbalanced.  Not much different between the two from what I can tell.


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@jl35 ,

Let me clarify my statement. I am sure there are more differences than I pointed out and the 2100 is a better piece, but I just noted what I know to be true.

I own the A-S1000 and I love it but would have no problem upgrading to either the 1100 or 2100 if funds permitted.

S/N ratios are higher by several decibels on the A-S2100 too.
the 6moons review seems to also indicate a better headphone amp in the 2100.  with the small price difference it is looking like the 2100 is worth the difference.  thanks all...
I was hoping the As2100/3000 would have come down on the used market. I'm thinking of picking a 2100 thru Assessories4less. People must really like them
I don't know if they are or aren't but if you do decide to buy from them, check to see if they are authorized dealers or Yamaha will not honor the manufacturers warrantly

From A4Less site.

"Accessories4less is a factory authorized reseller for Yamaha Factory refurbished products."