Keith...if you do not hear any anomalies and the sound is coherent top to bottom then that is all that matters (i.e., clearly there is not enough of a difference between the two amps that are showing up in the sonics). I agree with you that making sure amps stay within their linear range of output is key. It would be helpful for Joe to know the impedance curve for his D38s. Because if they dip below their 4 ohm nominal rating also in the mid- and/or treble-bands then the Cary 805s may still clip at those difficult load points.
PS: My name is Cyril (it's in my signature line). All the best
