My origional KSA5v with the blackgates has never shown any signs of clipping even when driving my k1000s at full volume( it drives them to a reasonable listening level at full volume ,but definetly could use more power then the krell can produce) but it is very clean sounding with no clipping at all. No way would I call the Krell thin sounding.
I have found the T1 to sound best with tube amps,I have never tried the T1 with it. I do own A Blackdragon recabled T5p I will have to give a listen with the Krell when I get a chance.
I also find the T5p to be picky with some portable amps but sounds great directly out of My Dell laptop listening to CDs go figure.