McIntosh MA5200

Thanks!

After the above conversation, I decided to check out Dynaudio's web site to see what they currently offer. I did a search and happened to come across a Stereophile review of your speakers. Normally, I don't read reviews, but I just wanted to see what they were using to power the speakers. This is a section from the measurements portion of the review.

"Sidebar 3: Measurements

I estimated the Special Twenty-Five's voltage sensitivity at 89.3dB(B)/2.83V/m, 1dB higher than the specified 88dB. The speaker is specified as a 4 ohm load, but as its impedance plot (fig.1) reveals, it drops to this figure for only a small range of frequencies in the lower midrange. The impedance actually stays above 6 ohms for most of the audioband, which, in conjunction with the generally modest electrical phase angle and the higher-than-average sensitivity, suggests that the Special Twenty-Five is a fairly easy amplifier load."

The only real choice here is if you like the sound of the MA5200. Having enough power for your speakers won't be an issue. Personally, I think it will sound very good. Especially with the built in dac.

@ 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.

" I don't like do-overs. Go with something rated for the load."

There's only 1 load here and it has nothing to do with the speakers or the amp.

"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."

And how do you come up with this? You're just guessing because you don't want to be wrong. Most 8 ohm speakers can and do drop down to 4 and below. If you look at this from a common sense standpoint, it eliminates most speakers on the market. Unless the customer wants to get into horns, or some other type of unusual design, what are you going to pair it with? You're implying that a Sony receiver in Best Buy rated for a 4 ohm load will be able to handle the OP's speakers better than the 5200. Does that make sense?

" 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."

That's not true either. They do it because they have to. Its the nature of the design. EVERY amp that uses autoformers/output transformers has to list the specs of the different taps they put on the amp. And yes, you can point out that some transformer amps only have 1 set of taps, like some of CJ's. True, but they still list it as an 8 or 4 ohm tap, and you can open it up and change the setting to 8 or 4 ohms. So those type of amps still conform.

Why don't you do your homework and see if McIntosh will back your arguments. I'm willing to bet they won't, unless you don't give them all the facts. The OP doesn't have an old pair of ML's or B&W theater speakers, he has the Special 25's. Although, not to get too far off point, I've owned both of those speakers, and unless the OP has a very large room and/or demands very high volumes, the MA5200 will have no problems driving them as well. But lets just stick with the OP's speakers, because thats reality. You may just find out that your experiences are not the only experiences that exist in the world.

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.

Well said. This is exactly why I stayed away from this amp as I have 4 Ohm nominal speakers. If it was stable into a 4 Ohm load, surely McIntosh would have published the specs. They did not and even went so far as to stamp 8 Ohms only on the back panel by the speaker terminals.

I am willing to bet if McIntosh was contacted, they would not provide a 4 Ohm rating. If they did, then again, why not say so out of the gate like they do for their higher level products. As for the stereo mags review that was sited, well IMO you have to take those with a grain of salt.

Again, I strongly considered this amp and auditioned it with a pair of Sonus Faber Cremonas, a 4 Ohm speaker. And while the MA5200 did drive them, the Marantz PM15S2 (90 wpc into 8 & 140 wpc into 4) did a much better job. So much so that this is the amp I went with to drive my VA's and have no regrets. I would suggest to anyone with 4 Ohm speakers to be leery of this particular Mac product.