Krell x-series, are ther any sonic benifits?

As many of you may already know, Krell is introducing thier new x-series amplifiers. Has any one had or taken the liberty of auditioning them? If so can you describe the sonic diferences between the FBP & X-series assuming there are any?

well I just sold my krell fpb 200c and I dropped it off at krell for the buyer to have the upgrade done and krell said there is a big diffrence between the two. If there was no diffrence why would they have an upgrade????????
I wonder the same thing? I have a krell 600c and think personaly if they just gave themselves a honest power rating and put an x in the name. It is only slightly different cosmetics. Maybee the output devices are different, if so I'll bet there is a slight difference, but not much.
Lev335: Why would they have an upgrade? How about the high end 2 channel audio business is dead, even more dead in this economy. How else can you squeeze money out of your customers if no one is willing to buy a new amp? AH UPGRADE FEES! I am not saying that nothing is done in the upgrade, I am saying that Krell created this upgrade to generate revenues. Why on earth would anyone buy a new amp when they could come here and buy them discounted or slightly used for 50% off?
I would tend to agree with Ericbee - Krell did it probably for marketing purpose. Looking at the specifications the entire new line of amp have the same weights and dimensions as their predecessors, yet they are each 100W more powerful. Since the size of the heak sink stays the same, one may assume that the number of power transistors also remain the same. So how do they squeeze the extra power out ? Perhaps by adjusting the operating region ? The amp may sound better than the replaced version but I suspect the improvement may be subtle. As always, the only way to find out is to do a side-by-side comparison. Has anyone done that yet ?
Side-by-side comparison for an individual would be difficult. I personally don't know of anyone who has a pair of FPB amps... However, I sent my 600c for the upgrade. Time will tell. Although I won't have the opportunity to compare side-by-side of before and after the upgrade, I usually hear the biggest differences in audio gear when I first insert it into my audio chain. So, I will report when I hear it.
Kichoi, please keep us informed. I would be keen to find out what improvement a $500 upgrade offers. BTW, do you use the KCT preamp ? If so, does Krell provide any upgrade to CAST II for it ?
Actually the 600C upgrade to 700Cx would cost whopping $2000... According to Krell, it will operate exactly the same as the new 700cx once the upgrade is done. It will have minor cosmetic changes; one on the face plate to make it identical to the new onces and a new sticker with 700cx ID for the back.
I have not asked them about the CAST II. I will do so.

In case I forget, please send me a note in couple of weeks. The amp is scheduled to be back in 1.5 week.
ericbee: great point but being such a large company like they are in regards to sales because they arent a big company in general. I would think that they would stand to lose many loyal customers if the upgrade was a small change in sonic quality. I sold the krell and went back to Levinson
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.