I would suggest you put the amp back on the floor to see if the "proper" sound returns. This kind of thing can happen with solid state amps. I have a YBA amp that I can dramatically change the sound on by simply changing the material I use under the amps feet i.e soft vs. hard material. Your amp, because it is transformer coupled, is less susceptible to changes in sound due to long speaker runs. That being said, the rule of thumb is to keep your wire runs as short as possible since there is no such thing as a straight wire with gain. All speaker wires introduce some coloration. The longer the run, the more pronounced that coloration becomes. I always think of speaker wires and interconnects as tone controls. G
My MC275 has a clueless sound-change...
I just moved my MC275 from the ground to on top of my rack. Same system and same cables, but the sound changed from musical, well tonal balanced... to thin, noisy, sharp, bottom-less... Anyone of you had such experience and can explain why would this happened? I have the amp sitting close (approx within 2-3 feet from the speakers' mid range section, can the magnetic field affects the operation of the tube amp? or is it that the cables needs to break in again after a few new bends... I am clueless, I switched my interconnect from my Pre to Amp... although it added weight on the bottom end, the mid to the top is still noisy, sharp and forward... please help...