Krell HTS 5.1 vs.7.1 for 2-channel only

OK. I need to get rid of two PrePros: I have several others but the 3 listed below are the only ones worth anything on the used market.

I have both HTS 5.1 (grey)and the 'newer' 7.1 (silver) ($4000 vs $8000 new). and a McIntosh cv31.

I DO NOT use the Krell's for my home theater anymore because of HDMI and well........ that's it. So I decided to give them a try in my 2-channel room to see if I should change out the old McIntosh Pre/pro 31v.

THE QUESTION(relates to the Krells Not the Mc): Which is better for 2-channel?? OR do they have identical circuits for the 2 channel analog? (HTS 5.1 VS 7.1)

I "auditioned"(A/B)the three processors last night using a rebuilt pair of Dahlquist DQ-20's (which have always sounded great!) and various combinations. Including LP's and CD's with a KAV-250a and a McIntosh MC 2002.
The Krell HTS's,either the 5.1 or the 7.1, are demonstrably better sounding than the McIntosh pre/pro, but the amplifiers sound very similar--keeping in mind that the Krell is 250w/C and the Mc is 200w/C.

I plan on getting rid of the McIntosh and one of the HTS's but I want to keep the Krell that has better 2-channel performance. I am gonna perform another test tonight of the two processors with some other equipment..............

I have searched, in vain, for the specs, as I am sure they are available, but I was wondering if any of you had similar experiences. Or know whether or not the circuitry involving Stereo in the Krells are the same. The used prices of both are similar, with the 7.1 obviously bringing a higher price.
I do not want to purchase another Pre-pro for my 2-channel room, but clearly the Krells out performed this Mc. (The Mc is about 15 years older so I shouldn't be surprized)
Thoughts opinions and science are all welcome.