Class A Coda 15.5 Vitus SS-102 or Gryphon Mephisto

The 15.5 puts out 100W Class A with a chassis temperature that is mildly warm, although individual units will vary. They will tweak up the bias higher if you request it, and it will be hot, but you will only gain around 5W of Class A. Unless you need that extra 5W in Class A to listen at your regular loudness, it does not seem necessary to me. Extra deep bass passages and orchestral bombastics may drive the amp into AB mode above 100W for brief seconds, but your ears will not detect it.

Stay tuned for the Coda S250 to be released in the Winter of 2015. Pure Class A at 250 watts per channel.

I'm not sure of your budget Goldman, but if you're mentioning the Mephisto stereo amp, well that's a $57k amp. At that level, you could also look at the awesome new Vitus SM-011 mono blocks. They're a definite step up from the SIA-025 and have a lot more power/control. The little Vitus amps seem to sound a bit warmer/more romantic than the bigger amps such as the SS-102. That said, the SS-102 sounds very natural, analogue-like and is the most unfatiguing amp i've ever heard. It is the only amp I've heard which tames the older YG speakers tendency to brightness and a 'metalic' sound. Even the little SIA-025 is a peach. It depends on your system needs and how deep your pocket is. One thing to keep in mind; Vitus sounds best with Vitus. If you go for SM-011 mono's or an SS-102, my next upgrade would be an SL-102 pre. Hope that helps!

Hi-Guys and Gals i received karan kas-600 and it put shame on lot of expensive amps This Karan has swept everything i heard in 20 years  and its getting better and better i have fitted mit oracle ma-x bal interconects and power cords and WHAT a difference but wait there is more fitted mit hd 60 speaker cables and it came all together i am over the moon Milan Karan builds best amps on the planet there are others but at 4 times the price forget it I am so blown away i will be getting signature version asi grand monos my ultimate dream if you have a chance go and hear karans and asi they will sweep you away as karan kas-600 has done to me