Krell FBP c versus FPB cx

I have just sold my KSA 200S and I'm interested to buy another amp. I was wondering what the difference between the FPB 300c and the FPB 300CX. Can anyone let me know?
I went from an FPB 300 non cast to a 400cx and the difference was not suttle. the 400cx is superior in every way.

also the 300cx is the old 200c

There seem to be some pretty good deals on the cx version.
Kenscollick is correct about the model numbers. Many people miss the fact that the 200C essentially became the 300CX while the 300C became the 400CX when the "CX" series came out.

I believe the "C" series can be upgraded by Krell to the "CX" series, but I do not know what is involved or how much it costs.

As for the difference, I'd like to hear about it too.

The "c" variants added the CAST connection scheme.

The "x" variant is an improvement to the sound quality -
a much "sweeter" Krell - and a move away from the old
Krell "house sound".

I wouldn't say the 300cx IS the old 200c; I would say the
old 200c can be UPGRADED to the 300cx.

That is they share enough components that one can morph
into the other. But they aren't equal in sound.

Dr. Gregory Greenman
Dr. Greg, Regarding your 200c to 300cx upgrade comment...that is what I intended to say. I am sorry if I was not clear.

Do you know how much this upgrade costs?
to upgrade to cast is 3000.00 endevor if your not the original owner.
I would probably go cast to start. the difference between the 200c and 300cx was night and day. 300cx is much better in my opinion.
I think the upgrade cost is $1K if you ae the original owner and $2K if second owner. That's what I was quoted for a monoblock upgrade. I bought three 350 CXs instead of upgrading my 250Ms. In general, most upgrades are too expensive and you are better off getting the latest version used on Audiogon.
I am mostly curious about the "C" to "CX" upgrade, financially and the perceived difference in sound. More specifically, the upgrade from the 300c to the 400cx.
There was a very similar post a couple of weeks ago, it was titled: Krell FPB300 vs 400CX
My previous post may help answer some of the questions here. Let me know if there's any trouble finding the old post and if so I can always post it here too.