I have the SE84UFO3 Monoblocks with the 25th Anniversary mods. These include beeswax bypass capacitors and an additional voltage regulation stage underneath the top chassis plate.

The proper Decwarian term for the effect of the power supply mod is "Density," but the most descriptive term is "BALLS!" The amps seem much more powerful in watts than they are, and more three dimensional and dynamic seeming.

In my past experience with an earlier model of Rachel I would call the Rachel sound a bit more forgiving and "soft" than the Monoblock sound; the Monoblocks are a bit more "ruthlessly revealing" and "clear" sounding. Each have their virtues.

Selecting between them really should be about your speakers. The Monoblocks would ideally be paired with 95 or higher efficiency speakers, and the Rachel may be able to drive 93 or higher. Crossover complexity should be considered as well as that can influence the efficient power of the speakers. . . .