MAC Autoformers?

I'm by no means an engineer, but very much appreciate the technical descriptions of why some amplifiers are designed with autoformers.

One comment about McIntosh owning the patent.  The patent on that invention expired long ago.  I think the more viable reason more amplifier manufacturers don't use output transformers for solid state amps is the cost and how much weight it adds to the unit.

I spent about a year visiting all sorts of shops to shop for a new pair of speakers.  The pair I finally selected (Focal Sopra No2's) match up with the MC452 "quad balanced" amplifier from McIntosh.  I've heard those speakers driven by amps which were called "fast" or "more detailed" (higher damping factor?), but the Mac (to me) just sounded more "musical" than the others.  Could it be the autoformer?  Maybe.  But I wouldn't sweat it if it was not!

" The only negative with Mac autoformers is in doubling the amplifier cost and weight"

So true!  I had to get help from my neighbor to get the carton from my car into the house, get the beast unboxed, unbolted from the plywood base, and lifted up onto my wall unit!

Wow!  Lots of opinions here!

In my case, my McIntosh MC452 pairs really well with my Focal Sopra No2 speakers, I can listen to them for many hours without fatigue.  I enjoy this combination very much, very much the only thing I really care about.

In my case I have a McIntosh MC452 (solid state amp with autoformers) driving a pair of Focal Sopra No2 speakers.  Focal lists the "nominal" impedance at 8 ohms, but the "minimum" impedance at 3.1 ohms, so my dealer recommended that I connect them to the 4 ohm taps on the amplifier.