Are integrated amps technically better than separates?

When you know what you want, and you want the best, a specialist is what you need.

he first statement is true. The second needs more explanation; as far as I can see its false. Regarding the first statement, over the years I've found that a lot of the improvements I've been able to make in our gear have related to power supplies. Arguably that's one of the trickier things that goes on in an integrated amp; IME it outweighs many of the other circuit topography issues! I totally get the connectivity issue- that is an advantage. But in most cases, its not *enough* of an advantage.

I have to agree.  In our components we have large power supplies.  Why, they sound better.  We repair all types of equipment and as already stated, much of the upgrades are in the power supply section.  I wish that could be accomplished differently but so far, we have not heard something that can replace a well designed and built power supply.  Out DAC has a 30 pound power supply.

Is an integrated better or an improvement over separates?  Unequivocally no.  However, the more important factor that may be missed in this query is: Have you found a synergistic combination with an integrated that is very magical and satisfying?  That answer is apparently yes.  Should you go out and spend a large amount of money trying to improve upon what you currently have with separates (chasing after a small improvement)?    Probably not but that is your call.
 

Have 2 high quality systems. One has separates - 2 mono amps, preamp - that list for $20k.
Other has $7k integrated. Sound quality is about the same, although they sound different. However, the room sonic characteristics dominate the difference in SQ between the two systems.
For me, the integrated is obviously more cost effective.

Not a good thing to put your sensitive preamp circuitry in close proximity to the power supplies for both the preamp and power amp.

One of my  preamps has a separate power supply that is connected to the rest of the circuitry by  special umbilical line - they recommend separating the two by at least a shelf or two in a normal stereo rack.  The power supply also functions to provide power to other components.

Certainly an over the top approach, but that reflects thinking at that time on the topic.

https://www.youtube.com/watch?v=-cXCFfec5mI

The power amp it plugs into is also pretty extreme

https://www.youtube.com/watch?v=RE5nlQ9LPYY