audio reseach ref 3 or krell KTC...?

Dave b, thanks. I checked with Aesthetix and they have reported that they do use coupling capacitors at the output for this form of protection against dc leakage. So, fortunately, no worries.

On another note, if one buys a FBP C vs. a non C version, is there any improvement if one is not using the Cast cables? Aren't there cast speaker cables? Do these just work with Krell speakers?

There is a 300C for sale that I am considering and only want to buy it if it is a step up (preferably sizeable) from my FPB 200?

Is it a 300cx or just c?

Just spent two weeks using my ARC ref 3 with an FPB700c without coupling capacitors - perfect match.
Preamplifiers having teflon or low leakage dielectric capacitors such as used by ARC or conrad johnson should not be a problem.

Dave b, it is a 300 C not the CX. I can get it upgrade to a 400 CX for $2,500 from Krell. Regardless, I bought it and am picking it up tomorrow. Hopefully it will be better than the fpb 200, which I already love.

Ckoffend, get the upgrade done to 400cx..that was my favorite FPB amp of all (better than monoblocks). Krell ended their golden age of audio design with the FPB cx series amps! You must get a Transparent MM reference power cord for it..you will crap your pants after hearing how huge a difference it can make.