I know I’m late to this dance, as well, but let me contribute some personal experiential feedback to this wacky thread because I, also, am struggling with a speaker upgrade choice for a 2 channel system with the MAC MA5200. I bought mine about 3 years ago. I know it’s entry level MAC but it is still, unquestionably, an outstanding integrated. I chose it after extensive critical listening to a Musical Fidelity M6si and the MAC’s higher priced Luxman competitor. I auditioned the MAC and Luxman in the same shop, same room, same everything for a couple hours. They performed virtually identically. I spent a little over 2 hours listening to the MF M6si in another shop (same music, similar components & speakers but different environmental acoustics, unfortunately) about 30 minutes before listening to the MAC and Luxman. Almost bought the MF because it was/is $1,500.00 less and spectacular. There’s no way I could say there was much, if any, difference between the MF and the MAC without a direct A/B audition under, of course, the same controlled circumstances. I bought the MAC, essentially, because of reputation, build quality and all of the other usual reasons people buy MAC gear. I don’t regret the decision, primarily because of the trade-in value MAC commands.
Now, onto the 4, 6 and 8 ohm nominal resistance question. In the last several months, I’ve done extensive critical listening to: Monitor Audio 500 and 300; Focal Aria 926 and 936; Triangle Esprit Australe EZ; Dynaudio Evoke 30; Vandersteen model 1 and 2 and Aerial Acoustics 6T. Unfortunately, all of the shops I went to for this used gear that made comparative analysis or evaluation difficult and, effectively, invalid, despite my best efforts to communicate my listening room dimensions, acoustic characteristics and gear prior to my appointments. One saving grace, however, was that each shop used the same "unfair" source components so that I could, at least, make fair A/B comparisons of the speakers I auditioned in those respective shops. In one, I was able to hear the Aerial Acoustics 6T, a phenomenal 4 ohm nominal load speaker, powered by a MAC MC275 amp and MAC preamp (can’t remember the pre-amp model #) presumably using the 4 ohm taps and, immediately thereafter, through the MA5200. You didn’t have to listen hard. The difference was immediately audible and would have been so, even to non-audiophiles with reasonably good hearing. The Aerial definitely sounded better, fuller, richer, more musical through that big tube amp with those 4 ohm taps. The Aerial still sounded outstanding with the MA5200 but nowhere near as wonderful as with the big MAC. (Pun fully intended!) The Aerial Acoustics 6T are a reasonably efficient or sensitive speaker rated, fairly & accurately, at 90 dB for 2.83 volts at 1 meter on axis. While I certainly do not pretend to be an expert on this (far from it), this experience and my ears lead me to believe that, even with highly efficient or sensitive less than 8 ohm nominal load speakers, the MA5200 will probably not be able to get everything out of those that a good 4 ohm rated amp will. Will it drive them? Sure. Without breaking a sweat? Sure. Both MAC Labs and other experts I’ve communicated with about this have told me so. However, driving them and getting everything good quality speakers like this are designed to deliver is a whole other kettle of fish! I think it has to do with the amount of current the amp can deliver.
So, back to the original question. What speakers should I go out and hear (after this Covid-19 thing subsides enough) that will pair well with the MAC MA5200? Should I stick with strictly 8 ohm nominal load speakers? Are 6 ohm nominal load speakers worth consideration? I don’t care about will the MA5200 drive them. I care about the best pairing and, yes, I know there are a lot of other considerations like listening environment, room placement and all that jazz but, just generally, what are likely to be the best playmates for the MA5200?
Thanks guys & gals!