Is it my amp or my speakers?

@millercarbon the reviews on those are great, but, man, 118#! and 54" high! there is the wife factor to consider...

@erik_squires it is a big, open room...

Thanks all for the v. insightful analysis. Got what I had hoped for from the community. Majority verdict: the speakers. I like the Tekton business model, but the array of speakers is way overwhelming (there were many fewer options when I purchased mine, 8-1/2 years ago). Back to the endless task that is research! Thanks to @smrex13 for the very good suggestion of "Places like Crutchfield and Music Direct have trial periods that will allow you to hear the speakers at home with your system. "

Finally had a chance to employ the very good advice and swapped out the amp to see if that was the problem. The only other amp I have is a Marantz AV receiver that’s been configured for 3.1 setup and a very different room dynamic, but I gave it a go anyway. The verdict: it *is* the amp. Even with the biases, the Marantz showed more detail than the Krell which, in comparison, sounded... muddy. So, now, I’m in the market for an amp: integrated, solid state, type A or A/B, not made in China, price <$3000. Any suggestions, please let me know. Otherwise, thanks again for the assistance.  P.S. I may still change out the speakers.

@alfa100 cleaning the contacts is a good idea. I know that the hearing in my left year is somewhat diminished (many years of driving convertibles), but my wife confirmed the audio issues and, I promise, she is not one to humor me. 

@alfa100 Sorry to report that cleaning the contacts made no difference (they really weren't dirty). Thanks for the idea, though.