Replacing my Krell FPB 600 amp with a tube amp

Meaning ill be back to the Krell FPB 600??

And others as good and better.
Your 800’s are a pretty nasty load from 200hz down where most current will be needed, 3ohms and up to -55 degrees of - phase angle, this can equate down to around <2ohms in the bass areas as seen by the amp.
https://www.stereophile.com/images/archivesart/88B800fig1.jpg

Trouble with Bi-amping, the internal xover of the 800's is right in the very sensitive area to the ear middle of the lower mids at 380hz and will be sharing this area with two amps, they better be similar in tonal character otherwise it will sound disjointed, as Almarg has also briefly pointed out.

Cheers George

George.. Thank you for the info. Maybe i would of been better off with this thread in the speaker forum. One thing i know is that i will be keeping these speakers. I will tell you that the Krell FPB 600 cruises with the B&W Matrix 800s. 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. Being all that said maybe id be better off keeping my Krell matched to my 800s. 

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