A Krell FPB-300 used to drive my Aerial 10Ts. From my perspective, it was NOT edgy and is a bright. I agree with the comments above: my findings are just the opposite as well. If anything, the FPB-300 is just sligthly on the warm side of neutral.
It wasn't until I replaced the Krell that I discovered its flaws. Compared to my Spectral DMA-150 Mk2, the the FPB-300 suffers a bit of grain in the midrange. Also, it's a bit slow, particularly in the bass (but then most amps are compared to Spectral).
If you hear bright and edgy then I think you need to address something else in your system, not your Krell.
Ken
It wasn't until I replaced the Krell that I discovered its flaws. Compared to my Spectral DMA-150 Mk2, the the FPB-300 suffers a bit of grain in the midrange. Also, it's a bit slow, particularly in the bass (but then most amps are compared to Spectral).
If you hear bright and edgy then I think you need to address something else in your system, not your Krell.
Ken