Class-D Amps for Maggies

[nightflier]

I know this has been discussed a bit already, but I wanted to see what others have experienced with pairing Class-D amps with Maggies. I'm a bit new to the Magnepan camp, but I've had many different class-D amps and have had very positive results driving box speakers. I'm driving MG12s in the front, MMG-C center, and MMG-W rears.

Recently, I replaced a solid state Outlaw 7125 seven-channel amp with a Class-D Rotel RMB-1077 amp in my system and had to give up some performance for energy efficiency. I'm also new to Rotel, but that little 17lb 1U amp uses a whopping 50% less energy at comparable volume than the Outlaw. The performance, however, is less stellar with the Rotel amp sounding thin and lacking body. Now the Rotel is a 200w amp into 4 ohms and does not have a rating for 2 ohms, although the manufacturer seems confident in the amp's abilities into more resistive loads.

In comparison, more powerful amps from PS Audio and Spectron don't seem to have this problem, but I'm left wondering if this is because they have more power or because they have better technology? Several online forums state that the Rotel Class-D amps are not a good match for Maggies, but they fail to explain why. If the Rotel is stable into 2 ohms, then it would theoretically have nearly 400w on tap for it, certainly enough to drive Maggies. What has been the experience of others out there?

[Feanor]

I know this has been discussed a bit already, but I wanted to see what others have experienced with pairing Class-D amps with Maggies. I'm a bit new to the Magnepan camp, but I've had many different class-D amps and have had very positive results driving box speakers. I'm driving MG12s in the front, MMG-C center, and MMG-W rears.

...

Yes, I've used a Class D with Maggies.

Specifically a Bel Canto eVo2i, Tripath-based 200 wpc at 4 ohms. It worked great for me although I prefer the Monarchy SM-70 Pro's I'm using today, (120 wpc/4 ohm).

From previous discussion, I surmize that you play much louder than I do and/or in a bigger room; (by your report, your Monarchy's got pretty hot: mine don't). So maybe you need 300+ wpc. But wait, (there's less ): bear in mind that the smaller Maggies, MMGW, MMG, MG12, are output limited, i.e. beyond a certain point they begin to sound compressed regardless of the amount of power you feed them.

Some people just don't like switching amps but these people tend to be either tube users or very high-end S/S users running the likes of Pass Labs, Ayre, Edge. What the heck? Isn't it you who've got the Spectron? Some reason you're not using it? TAS pundits rated the current Spectron model top among the class Ds they tested and very close to the Pass/Ayre/Edge category.

[nightflier]

Yes, the Spectron is fantastic, but XLR only and I don't have adapters (which I would really want to avoid, anyhow).

The MG12s are output limited? That's news to me. What exactly does that mean?

[Feanor]

Yes, the Spectron is fantastic, but XLR only and I don't have adapters (which I would really want to avoid, anyhow).

The MG12s are output limited? That's news to me. What exactly does that mean?

Well, the MG12 will be a lot better than the MMG. I've only owned the MMG, but I certainly found that they would not play loud without sounding compressed, (i.e. lacking dynamic range), even with 350 wpc. This is because of the inherently limited area x excursion of the bass drivers on smaller Maggies.

To enjoy, say, orchestral crescendos with the MMG I had to use a subwoofer with high and low pass filters at 80 Hz. Only with those relatively high settings, which keep all the low bass out of the MMG, I could get a reasonably uncompressed sound. Of course the MG12 has a significantly larger bass drive and will be better.

You could try the Spectron with hybrid RCA/XLR cables like these from Markertek; they come in range of prices. Of course you'll want XLR male -to- RCA male.

[blackraven]

It could be a matter of current and headroom. Maggies like lots of current and headroom. They will take as much clean power as you can give then and that is coming right out of one of the magnepan engineer's mouths. When I visited the Magnepan factory here in White Bear Lake I asked them specifically how much power was too much? My question was aimed at the 1.6's. It can't be much different for the MG12's.

I can tell you that when I went from using an Adcom 260wpc AVR to the Parasound Halo with 400wpc and peak of 750wpc, the 1.6's really came alive. The dynamics just exploded.

[Feanor]

It could be a matter of current and headroom. Maggies like lots of current and headroom. They will take as much clean power as you can give then and that is coming right out of one of the magnepan engineer's mouths. When I visited the Magnepan factory here in White Bear Lake I asked them specifically how much power was too much? My question was aimed at the 1.6's. It can't be much different for the MG12's.

...

You can believe me or not, BR.

I drove my MMGs with >350 wpc; it didn't help. The reason is the limited surface area of the bass driver on the smaller Maggie. The MG 1.6 has a much larger bass driver and doesn't suffer from the problem to nearly the same degree. However this problem affects all full-range planars to some extent.

[blackraven]

Feanor, I agree with you concerning the MMG's. The MG12's are a big step above the MMG's. My comment was aimed at the 1.6's and MG12's. The MMG's are weak and anemic compared to its larger brothers.

[nightflier]

Other than size, how are the MMGs different from the MG12s?

[Feanor]

Other than size, how are the MMGs different from the MG12s?

Not much different otherwise -- but size matters!

[blackraven]

The MG12's have a larger sound stage and depth, better bass and treble, have a larger sweet spot, image better and overall more detail to its sound than the MMG's. Music seems to open up the larger you go with Magnepans.

[hifitommy]

to have class d amps that will perform without embarrassing themsselves. i was privy to some $60k von schweikerts playing VERY loud on the american beauty score cd. the sound was nearly flawless. upon inspection, i found the amps were channel island audio D200 monoblocks which retail for $2300/pr!

yeah, i was impressed with the vSs but what REALLY impressed me was the amps and their price. cia just came out with 500 watters for $5k but i cant see the need. reason? my friend uses the d200s for his mg12s and the sound is incredible. they can be had with single ended connection or SLR if you want.

i have MMGs and drive them with my adcom 555II and a hsu sub and to be honest, i just LOVE the sound. loud is not a problem and i havent been bothered by compression. see my profile for room size. i will say that the mg12a give a bit more texture to acoustic guitar but i am fine with the babies.

[nightflier]

Yes, I heard that VSA and CIAudio voice their products to each other. They are often paired together at audio shows. That said, they are both in my neighborhood and I've had great communication with CIAudio, but nary a peep from VSA, and I've tried several times - I guess they just don't feel they need to be that responsive to their customers.

On the lower-priced front, I really have to say that CIAudio mades great little amps. I've played around with a demo pair and it was certainly a capable one, although this was before my Magnepans.

I'm also curious to know if anyone's tried the PS Audio Trio amps with Maggies. PS Audio seems to think this is a great match-up and claims several happy customers, but I haven't seen anything online corroborating that. Considering that PS Audio doesn't have any other amps, I'm almost wondering if they're getting out of the amp business. That would be a loss.