Okay I Bought the Magnepan 3.6's

Wait!!! Did you buy the Maggies new or used? If they are new you really need to let them break in for a couple of hundred hours in order to be ale to evaluate amps. The sound of Maggies changes significantly over the first couple of hundred hours and what you describe with the Mac could be attributed to them not yet being run in.

If you go Pass, I would go to the 250.5 or 350.5. I know with my 2.7's they didn't start to sound right until I had 600w/ch per side (4 ohm) going through them. Others have mentioned the big Brystons as they work well with Maggies, and I agree they are worth checking out. Despite what you get, I would make sure you are at least at 500 w/ch.

I don't think the 150.5 is enough, especially in your room. There is a reason so many are recommending huge amps like the Wyred for Sound, Bryston 14Bsst, or Pass 350.5. The maggies are not very efficient and will run through the 150.5's 300 watts in no time. Going to an amp like the Wyred for Sound or big Bryston will net you another 4-5 db's of headroom, a significant difference.

I like Pass stuff, but think it is extremely expensive and not worth twice as much as Bryston, with the 350.5 running nearly $12,000 for a new one, vs. the Bryston's still expensive $6,000. The Wyred for sound ST-1000 as the comparative bargain of $2000 gives you 1140 watts per side, a 6 db increase in output capability over the X150.5 amp. It also leaves a lot more cash in your pocked for other things.

Bombaywalla,

You are correct the Maggies are a relatively benign load in terms of current requirements; as long as the amp is comfortable into 4 ohm loads, there shouldn't be a problem. What you are forgetting is that Maggies do suffer from dynamic compression that gets worse the harder you push them. Your calculations would be correct if they were linear, but they are probably suffering from 2-6 dbs of compression in the mid 90 db range.

My experience with my 2.7s was that with 200 watts behind them, they were completely underwhelming. When I borrowed a friends older Yamaha M80 amplifier (330w/ch) I flat out would run it out of power, the VU meters would light up like a Christmas tree in Times Square. It was only when I bought an Adcom GFA-5500 (350w/ch with 1.7 db of headroom i.e. 500 a side on peaks) that they started feel better. Even with the Adcom, I would light up the clipping lights on loud passages. I ultimately ended up with a Sunfire Stereo (600 per side) and if I could swing it would go to the signature version at 1200 per side. This was all in a 14 x 17 foot room.

The x.150 puts out 300 watts/ch into a 4 ohm load, which as others have said is not adequate from their experience. My experience says that 300 watts/ch in a smaller room wasn't adequate, so I have no reason to believe it would be in a larger room.

The article you cite in Stereopile sums it pretty well when the review says "Another consideration is that although the 3.6/R is a benign load—mainly resistive and a fairly flat 4 ohms—at 86dB/2.83V/m they’re not terribly sensitive. The VAC Renaissance 70/70 is an unusually strong 70W amp, but wasn’t really enough to make the Maggies sing. The Mark Levinson No.20.6s, VTL Ichibans, and Classé CAM-350s all did better jobs of resolving low-level dynamics and detail, and opened up the soundstage noticeably. I spent time with all three, but ended up preferring and doing most of my listening with the Classé monoblocks, which are rated as delivering 700Wpc into the Maggies’ 4 ohm load."

DNE, when you say the Pass is really a 250watt amp disguised as a 150 watt amp, that is a bit misleading. Most well designed high end amps will handily exceed their rated output by 1-2db's, the amount of out performance you claim for the Pass. I think the pass is a great amp, if I were rich, I would buy one, but I also think given the size of the buyer's room, and fact that he was not enthused with the McIntosh 402 with 400 watts per channel and 2 dbs of headroom, that he would be well served by having the extra 3-5 dbs that a bigger amp would put out, whether from Pass Labs, Bryston, Wyred, Sunfire, McIntosh or any other number of excellent manufactures.

For Stickman, I have to ask if you watched the meters on the Mac when you were using it. For the levels you wanted, were you getting close to clipping it? That would give everyone a better idea of your power needs.