When you switch from a stereo amp to mono's of the same brand, you will get a bigger soundstage, better seperation. Your bass is also tighter and more control. Music sounds more natural and effortless.
In rare cases those who have bought instages end up losing some sound quality.Best to ask about amop in question to those with experience if you were thinking say of geting a Brytston 4BST and then anotther.Not to say that this is one of those amps but monoblocs on the whole do sound ebtter but ecoonomizng by doing it in stages may not yield as good an outcome and one might be beter buying those amps in mono configuration if offered or larger stereo model.Rare but sometimes the case from what I have read here and Ayslum.
Libertasdon, the preamp runs to the amps via interconnects, and the amp (or amps) connects to the speakers via speaker cables.
If you have two speakers 8 feet apart you can put the preamp in the middle and then one monoblock amp next to each speaker so only a short speaker cable would be needed.
A stereo amp can only be in one location, so even if the amp was located in the middle between the speakers, the speaker cables would still need to be longer than they would for monoblocks located right next to each speaker.
Look at some of the pics in Audiogon's virtual systems section and you will find some examples of this arrangement.
Libertasdon, you place the amp near the speaker and connect it with a short cable. Then you run a loooong interconnect from the preamp's output to the monoblock amp's input.
You've moved the lengthy connector cable from the speaker-amp interface to the amp-preamp interface. It's a good idea. Generally, top-quality interconnect cable is cheaper by the foot than similar speaker cable; also the amount of wire hanging off a speaker affects its impedance more than the interconnect wire affects the preamp's.
The crosstalk in stereo amps is insignificant, and cannot justify monoblocks. Also, there actually may be some advantage to having one big shared power supply, rather than two smaller independent ones, because there will be greater headroom when only one channel has a peak demand. Most stereo amps benefit from having one channel run out of phase, as this results in a more even draw from the plus and minus rails of the power supply.
I like monoblocks, but just for the short cables and lighter weight.
This is far from objective analysis, but since I purchased my first set of B&K M200 monoblocks, I've yet to find a stereo amp that can touch them . . . and the unit's I've compared to cost me anywhere from 1.5 - 2 times as much as I paid for the M200s pair.
The form factor has advantages (eg, running shorter speaker cables, location), and disadvantages (eg, size)