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.

These thoughts have been mentioned, but- I'd like to agree: Having two separate power supplies, and being able to place the amps much closer to the speakers(shorter cables) are two big advantages to using mono blocks. One would only need balanced interconnects if the system were in a high RFI/EMI environment, and then only if the interconnects needed to be fairly long.

If the particular stereo amp sounds like crap........it is not likely that his mono clone will sound any better.

Maybe
Better channel seperation (cross-talk)
Better (lower) total harmonic distortion
Seperate power supply for each channel (not always the case tho.)
Mono-block designs are usually reserved for top shelf models or
statement designs.

If in fact , both amps (mono blocks and stereo) are using exactly the same parts and circuitry the differences will be not worth going nuts about.

In short
base your decision on quality of the component, setup requirements and most of all, your personal preferences.

As to recommending a particular amplifier..........
well , there is no easy answer to your question.

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.

Thank you for all your responses. To clarify further my speakers are rated 20 watts to 500 watts. I am considering the Pass Labs INT 150 versus their XA 60.5 monoblocks, which I know complicates things because it is an integrated amp. It is appealing to me becuase it has the new XA.5 technologies in it as best I understand. But the downside is that I really like my current AH preamp. I am not yet aware of a high quality stereo amp in the price range mentioned new or used that I should be considering.
I am further uncertain about wattage - as best I understand if the 60 class A will drive the speakers loudly enough, then is it necessarily true that other things being equal that 200 watts class A would be better sounding?