Preamp to mate with Krell KSA-50 mkII

I would like a few opinions on which preamp to mate with my Krell KSA-50 mkII amp. I am going to try a Conrad-Johnson PFR this week. Anyone tried that particular preamp with the Krell? My system consists of:

Sonos WIFI music server
Krell KSA-50 mk II
KEF Reference Model Three
Energy Veritas v1.8
Analysis Plus Oval 9 speaker cables
Harmonic Tech ProSilway mkIII interconnects
Kimber Illuminations D-60 digital cable
I would re-think the clutter and get a krell 400xi mated to an SACD or other balanced player connected with musical cables like MIT shotgun or magnum (HarmTech is also one of my favorites). Use a great power cord from Transparent or MIT as well. This simple approach will yield more rewards than almost any combination of gear money can buy...speaker update maybe as well?? Otherwise, try the Krell 280p...a giant killer indeed.

I have an old KSA 50II which I use with an Audio Research Ref2. In general old Krell amps seems to like tubed preamps. I had a Conrad Johnson that also worked well.
You could do well with an ARC LS25 used..the 6922 tubes were far more musical than he newer 6H30 designs. I owned the LS25 and Ref's 2 and favorite was the LS25!!
I have owned the Krell 400xi, 300iL, and 500i. The KSA-50 sounds better than all of them. I used Transparent Ultra interconnects and speaker cables with both the 400xi and 500i. Transparent cables match Krell very well and many Krell dealers I have seen use Transparent cables on their display systems. I have tried over 100 pairs of speakers (anywhere from $1000-$10000) over the last 11 years and keep coming back to my KEF 's and Energy's!!
My old Krell KSA 50MkII worked very well with an Audio Research SP11. ARC gear serems to work well with Krell amps, and I imagine CJ might as well.

Keep the KSA 50, it is a remarkable amp.
Krell never made a 500i and a system is only as good as it's weakest link so try before you buy if possible and don't forget the power cord issue..transparent MM reference PC's are magical!!