mono versus stereo ampflication

Usually the builder offers mono amps as the very top offering in the line. Usually they DO offer the best parts and represent the very best effort of that builder - if offered.

I know that the power supply in my mono amps will not fit into the stereo version. That is just one example.

So contrary to the rather strong comment above, mono amps are often times the best effort available by a given company. The extra chassis does cost more and that is but one reason mono amps do cost more. Seems rather a simple question to me.

If it is just a matter of all the same parts in one amp vs splitting them up into two, then the improvement would come from better isolation of parts, less crosstalk etc.
But again, usually you get double the power supply and we all know that is where LOTS of an amp's improvement can come from.

Forgot to finish off by saying one builder's stereo amp can cetainly sound better then another's monobloc amps. Impossible to answer that part of your question without knowing the specific amps in question.

You can purchase TRL M225 monoblock amps brand new for only $5500. They put out close to 300 watts per amp and I have not heard better. The TRL stereo amp, no longer being made, beat the new $7500 CJ Hybrid (ET250S) amp by a good margin when I heard them both side by side this weekend in my friends home.

The new monoblock amps from TRL are a big step up from the old stereo amp so that should give you a good idea on how good they are.

I am confident you will find the m225 amps as good as it gets regardless of $$$$. They sound great with a nice tube pre like your AH.

Many mono's do have better power supplies & transformers etc. They are "overbuilt" to a higher level if you will.

The TRL amps are single ended only. I have not heard a Pass Amp and understand they are quite good.