My current Tube Monblock amplifiers do sound different from my equal level quality tube stereo amps I moved from to the mono amps. And, different yet again from my last two dual mono solid state stereo amps. The channel separation, instrument placement, sound stage presentation, and layering was immediately evident with my current monos.
I'm fairly convinced now it would likely take a much more expensive dual mono stereo amplifier to provide similar results to my current monoblock amps - fwiw.

