Replacing my Krell FPB 600 amp with a tube amp


Im thinking of replacing my Krell FPB 600 amp with  tube amp . I really love the power and bass slam of the Krell FPB 600.Could i possibly find that with a tube amp? I was thinking of the ARC Ref 250 mono blocks. I am also using an ARC Ref 6 preamp. The only thing i can think of with this much power and bass slam would be the ARC Ref 750se. Any other suggestions and how would the ARC Ref 250s as compared to the Krell FPB 600. 
tattooedtrackman
The technical guys, Almarg, Eric and a few others are invaluable to this site. If you love these speakers as you say, the advice from these contributors can be helpful in keeping you from making a bad choice.
Had no idea the CAT amp had such a low impedance. 

Thanks for the nice words, Dentdog. I found that information about the CAT JL2 in the measurements section of this review of the Signature Mk2 version of the amp, in SoundStage. The data provided near the top of the measurements page states "output impedance at 50Hz: 0.7 ohms." And the damping factor measurements shown in Chart 4 indicate a damping factor of about 11.5 across nearly all of the audible spectrum, with a slight decrease to about 11 at 20 Hz and 20 kHz.

I’m not sure what output tap or taps the amp provides, but a damping factor of 11.5 corresponds to an output impedance for an 8 ohm tap of 8/11.5 = 0.696 ohms, and less than that for a 4 ohm tap.

Best regards,
-- Al
tattooedtrackman OP
But i was just thinking how a tube amp would sound and be with these speakers. And i never thought of it sounding disjointed bi amping until you and Almarg briefly pointed out.

That’s my take on it, and as I said before " The better I made all my tube amps sound with mods/circuit changes, the closer they got to the best solid state."

Being all that said maybe id be better off keeping my Krell matched to my 800s.

That’s the way I would go, and for the itchy upgrade feet, I would look at updating the Rega Isis cd player to something really good with volume control that drives the Krell direct,and pocket money selling the preamp.

Cheers George
George ......I cant see selling my ARC Ref 6 preamp and Rega Isis cdp to even something really good with a volume control that drives the Krell direct and have it sound half as good as with the ARC Ref 6 pramp. I even upped from the ARC Ref 5se to the 6 just because it was that much of a HUGE improvement over the 5se. The sound that i have acquired with my new ARC Ref sounds phenomena to ME. "I should not mess with a good thing". IMO now. 
That’s fine, to me the stars of your show are the amp and speakers, you’ve, got the megabuck cables, all that left for me with questions is the rest to change/re-configure, can you get more spread between the speakers, they are very close, or have you bought the right one in a couple of feet just for the photo? 
https://systems.audiogon.com/systems/6134

Cheers George