Should I upgrade my Krell FPB 200c to cx300?

just the fact that the new 300 severely devalues the old 200 as far as resale or trade in should be enough to convince you to upgrade.I upgraded my 300 to a 400cx and the amp performs with more authority. everything the previous post mentions is true as i also have the kct pre amp.

How much does the upgrade cost?

I currently have the version of FPB-350M that was made prior to "CAST". I use these with a tube pre-amp, which I do not intend to change. Therefore, does anybody know if these performance improvments (after upgrades) hold true while not usung the "CAST" feature between Krell components?

Well, you actually sort of lose either way. If you don't upgrade, you'll be wondering how much better it would have sounded. If you do upgrade, you're out the cash.

A third alternative is to send the amp to me. This costs less than an upgrade and solves all those nagging problems with voices in your head talking about "CAST" and "dynamic envelopes" and "authority". I certainly wouldn't call you up and talk about that stuff. The amp would also sound better over here than at your house. Let me know.

Mcx also optimizes balanced inputs by speeding up non CAST connections to make them sound much faster than non Mcx non cast connections. Don't sweat the tube pre, I'm sure it sounds fine. You don't need to have all cast to benefit, but when you do it is cumulative. If you are looking for addt'l speed and a slight increase in smoothness on top and midrange, consider it, if not then you won't miss it much, especially if you're already digging what you hear. Out of curiousity, what is your pre?