Krell x-series, are ther any sonic benifits?

Actually the upgrades will cost $500 per chassis if the units were bought October of last year or later, $1000 per chassis if bought earlier and $2000 if the amps was bought used or from an unauthorized dealer.

This last weekend I listened to the 400cx driving KRELL LAT 2s pinched-out at 80Hz while a pair (yes, a pair) of KRELL Master Reference Subwoofers handled the bass from 80 down, and it didn't suck. We didn't have a 300c to compare, and the 400cx was under 48 hours young. It does run hot like FPB product always has, and it was every bit as smooth, incredibly dynamic, and detailed as previous product. The only shortfall, in my jaded opinion, was the fact that we were using a DVD Standard and an HTS II (albeit CAST from the HTS II) up front. I feel there is no substitute for the KRELL 28c/KCT combo in such a system, and it was noticeable. The CAST II catches up to the CAST circuitry already present in the 28c, KCT, MRA, and MRS. The only upgrade to the 25sc, 28c, and KCT is a sliver center pillar top trim piece like that on the top and bottom of the center pillar of the X Series amps. The new cosmetic looks good, but it is subtle.

Krll, are you a Krell guru? To everyone else who reads this, the answer is definatly yes, this guy actualy does know the scoop quite well. I would take his word on any Krell question. I wonder though why the guy who had the MR subs, where you auditioned the new amp, has such pussy front end? Why doesn't he get the sack to put in a KCT and 28c? I totaly agree with you that the HTS is not KCT equal, nor is the DVD standard a substitute for the 28c ( although a very good all around substiute for the music-movie one box guy ). Cast is the only way to fly. As someone once said to me,"Got a problem with more bandwidth?" Thanks for all the help Krll!D

700cx arrived at my house and I fired it up last night. Sony SCD-XA777ES -> BAT VK-50SE -> FBP700cx -> B&W N-802

Even out of the box, it sounded different than what I was used to before it went through the upgrade. It sound more transparent than what it was - showing all the VK-50ES can do the tube magic (and not necessarily the most accurate reproduction I could have achieved with KCT with CAST II).
However, to my ears, it has perfectly balanced (unnatural) euphonic sound with detail, tranparency, and dynamic sound that is very pleasing.

I will report more as I learn further.

Ki