Yup....The Plinius that I mentioned in my OP was the original SA100 MkIIII have a Krell 2250 from the early 2000's (not class A or anywhere near the FPB series) and much prefer it to my Plinius SA103 CLass A !
A fine amp, the AB to A toggle switch was a gem, great idea, but sonically the Big K is light years ahead.
All the soundstage of the Plinius , but extraordinary grip on the bass , and fast and snappy on the top
Thankfully, I have the Vitus into the same pre, so can do AB for general listening, and K for weekend "critical listening" , and room warming duties.