@ ZD542: Of course speakers don't have a uniform impedance. 8, 6 or 4 are merely nominal ratings and very few companies ever explicitly state the range. One exception is Martin Logan, where their manuals do state a minimum impedance. A friend who recently purchased a pair of ESL EFX found that they can go down to 1.6 ohms @ 18+ kHz. His Hegel H70 wasn't up to the task even though they state they are stable down to 2 ohms.
The reality is that the MA5200 is designed for an 8 ohm nominal load, not 4. Given how well make Mc is, it won't fail, but it is safe to predict that it won't sound its best either. I have learned from hard experience over many years of listening that matching the transducers to the electronics is about half science, 25% personal preference and 25% blind luck. Some stuff that should sound good doesn't, other stuff is the opposite and sometimes very minor tweaks can make major differences. That's one reason why Mc puts 8, 6 and 4 ohm terminals on their higher end models and publishes stability ranges.
BTW, I have a MC7100, and the manual rates it for 8 and 4 ohms nominal only, with 100 W into 8 and 150 into 4, which is a very different result from the MA5200. I run it bridged, where it's rated for 8 ohms only into a B&W HTM 62 that's 8 ohm nominal with 4.3 minimum. Works beautifully.
Ultimately, Jimmymac will have to make up his own mind, but I tend to be conservative where this kind of money is involved. I don't like do-overs. Go with something rated for the load.
The reality is that the MA5200 is designed for an 8 ohm nominal load, not 4. Given how well make Mc is, it won't fail, but it is safe to predict that it won't sound its best either. I have learned from hard experience over many years of listening that matching the transducers to the electronics is about half science, 25% personal preference and 25% blind luck. Some stuff that should sound good doesn't, other stuff is the opposite and sometimes very minor tweaks can make major differences. That's one reason why Mc puts 8, 6 and 4 ohm terminals on their higher end models and publishes stability ranges.
BTW, I have a MC7100, and the manual rates it for 8 and 4 ohms nominal only, with 100 W into 8 and 150 into 4, which is a very different result from the MA5200. I run it bridged, where it's rated for 8 ohms only into a B&W HTM 62 that's 8 ohm nominal with 4.3 minimum. Works beautifully.
Ultimately, Jimmymac will have to make up his own mind, but I tend to be conservative where this kind of money is involved. I don't like do-overs. Go with something rated for the load.