Mono Blocks / why are they not more prevalent? + Wyrded4Sound SX1000R

The true value of mono blocks are realized when the speakers demand the dedicated power supplies and output stages in two separate chassis. This is true when speakers are particularly low efficiency. 
fir high efficiency speakers the value diminishes and it becomes less of a priority.

Typically, the monoblocks handle transient loads a lot better when the speakers demand it. The drum attack becomes immediate, the bass sounds tighter and generally “speed” of the speaker response increases.

thus improvement is less audible on efficient speakers as you hardly find yourself lacking output.

my 2 cents.

MO

@mendef 

As mentioned by @moamirkalali there are situations with gear where, in my case, I was changing from a SS system to a tube system (because of equipment failure) but wanted to keep my speakers (KEF Reference 205/2’s) that are a bit power hungry…

Going through the assortment of tube amps offered by McIntosh (my system is all McIntosh - can see in My Systems) the choices were considered based on power supplied, price and esthetics. I chose the MC275. However, unless mono-blocked didn’t produce enough power to adequately drive the KEF’s and individual REL S/812 subs. I don’t play music super loud but occasionally crank it up for a particular track of music. It’s nice to have the power when you want it. At the mono-blocked MC275’s 150wpc the power delivered is adequate for the KEF’s but not overdone. My system sounds GREAT, by anyone’s standards.

Go mono-blocked if it suits you. Don’t worry about whether it’s a popular thing to do or not!

IMHO...  When you look at today's stereo amplifiers, (CODA, Pass, etc....) their robust linear power supplies with tons of low ESR capacitance blurs the lines between their mono counterparts in terms of channel separation, soundstage and general sonic quality.  Over the years, I have had big stereo and mono amps and in minimal cases did I hear any real meaningful differences in sound quality parameters between their stereo and mono versions.  Now with space constraints, I have two different stereo amps (one pure class-A 90 WPC and one class-A to 100WPC, then 300WPC A/B) besides sounding slightly different, leave no wanting for their mono counterparts in terms of sound stage and other desirable sonics.  Perhaps if your system is that discerning or you have speakers that really demand a lot of current, the stereo/mono differences IMHO should be minimal or not noticeable.  

For the audio gear head guy, Mono Blocks are the way to go. Why not prevalent? it all about $$$. If I can afford, I would go mono blocks

More money (2x), limited space..  Im my case, more heat.  When I walk past the room where mine sit, I can feel the heat emanate into the adjacent hall.  I live in the Phoenix desert.  Not everyone can deal with the heat that comes with mono tube amps. Plus, my speaker and inefficient and current-hungry.  Monos spread the load.  Some folks like to keep a system simple.