McIntosh Loses Midrange... Help

I have another thread about a specialised electrical outlet that I thought might be the source of a problem I'm having with my system where it's gone lifeless. Further testing and analysis has led me to realize the midrange is dead. That's where the life is in music and the lack of it could be why my system sounds lifeless.

Is there anything that might cause a McIntosh amp to lose its midrange, or any amp for that matter?

Additional components include Rega Jupiter CDP (new and still breaking in possibly though it's been a long time already), Tannoy D500 speakers, Harmonic Tech TruthLink interconnects and generic speaker wire. I've done lots of switching interconnects and components and outlets and still have the same problem, even with another CDP.

Any thoughts on whether this might be a McIntosh problem that needs correcting are appreciated.
I don't believe it is an amp problem. For the midrange to go, there must be changes in circuit bias which is dependant on only a few components. In other words, it is all or nothing as far as the amp is concerned.

Do you have any other speakers to try? It could be a driver problem IMO (although agreeing with Rwwear). Try good speaker cables too (MIT is what I have and love it) since you may be getting inductive voltage drops at certain midrange frequencies (specified by high generic cable capacitance). I think the amp is the last thing to suspect.
Actually things have improved dramatically. My guess it was the break in of the outlet I installed. Shame on me for blaming a Mc amp!

Which MIT speaker cables?
Budrew, I almost replied to your other thread on the 'fancy outlet'. I looked at the BC site and saw that they're selling ACME outlets. I've run in 8 of these in my system, and there are periods during break in where the ACMEs sound very dull and lifeless as you described. You may hear this again at some point. They took a little over a month to stabilize in my system. Hang in there. I've seen some threads where people have given up after trying the FIMs for just a few days. Both sound excellent once thoroughly run in, although both have very different characters sonically.
Hey - Glad to hear that the problem is clearing up! The MIT cables I have are all Terminator 2. The speaker cables are biwire. I am extremely happy with them. They beat the Kimber PBJs I had to pieces.
I have the non-cryo 20 amp version. The ACME IMS has a very quick and transparent sounding mid-bass, and presents a wealth of upfront detail. Not etched sounding, but you get the sense you're hearing everything in a very transparent space. I was quite happy with the ACMEs until I heard the FIMs in my system. The comparison made the ACME sound like its tonal balance was tilted up in the upper mids, and by comparison a very fine dry grainy quality became noticeable from the mids up. The FIM is slightly darker, but more natural and smoother sounding. Initial impression with the FIM is that there isn’t as much detail, although its all there, some details just have a more distant perspective. Just my take.