Krell FPB 300 vs ML 333 for Thiel CS6

Funny thing is that I have had/have all the amps you have, but slightly different models (ML 331.5, Krell FPB 200, Proceed HPA 3-channel amp). I had Thiel 2.2 speakers. First thing is that typically when I ran the Thiels they were part of a second system that was run directly to the amp by an Audio Aero Capitole CD player. This is a very warm CD player, so this must be taken into consideration.

The ML 331.5 I felt was an excellent match with the Thiel speakers. The bass is not going to be as strong as with the Krell (in my case), but it seems that the ML tamed the potentially forward tweeter of the Thiel a bit more than the Krell did. I almost got the impression that the ML rolled off a bit in the upper frequency range compared to the Krell. This could of course been the interaction with the Capitole. For what its worth, for the most part I kept the ML with the Thiels and the Krell in my other system

When I bought the 331.5, I bought it from a guy who had 7.2 speakers and heard them when I picked up the amp (with the ML amp). That was my first time really listening to Thiel speakers and I was very impressed by the match (even though I think the 331.5 was a bit short in power for the 7.2 speakers).

I have aFPB 300-C coming on Tuesday and I think you would be very good with both/either, certainly better than the Proceed.

With regard to FrankC's comments, I cannot say that I ever had a problem with my 331.5, but am not sure if the .5 upgrades there were done addressed these cap issues, it would not surprise me as I have heard others mention some "minor" reliability issues. My 331.5 performed flawlessly for me. I had a pass 150.5, which was a good amp, but I never played this with the Thiel speakers so I cannot comment on this synergy, but I have heard good things about others running them with Thiels. I ran Totem's and Von Schweikert with the Pass amp. Again, though, I did like the sound of the ML with the Thiel, but would consider Frank's comments. If a ML 23.5 had enough power, that is a very good ML amp, but think it will be under powered for your speakers. I loved the Krells with Wilson speakers, both the Duettes and the W/P which have several common characteristics with the Thiels, FWIW.

I cannot tell you the cost of the .5 upgrade on the ML (but would imagine that this would be easily attainable information directly by e-mailing them), but it is my understanding that yes, it does need to go back. Also, with the Pass Labs, the .5 versions are reportedly a fairly noticeable/recognizeable improvement vs. the non .5 versions. But to be honest, I have never compared the two Pass units to confirm this myself. I know the upgrade for the Krell C version to the CX version (for a FPB300-C to go to a 300-CX) is $2,500 including the new center cap faceplate (Krell just sent this to me on Friday). I think with the ML, the cost of the upgrade might be variable depending on whether you update the faceplate as well.