Pass, Bryston, Audio Research, or McIntosh?

Several comments:

1) You are in the price range of the Pass Labs pure ClassA vs ClassAB amps. They are different, and I would try them. So, for example, XA100.5 or XA160.5. The Maggies have such a pure upper midrange, and pure class A makes that sing quite beautifully! Note I would rather have ClassA at lower watts than ClassAB. However, I have Maggie 3.6s, not 20.1s, and with push pull and all that, maybe you need even more watts.

2) If you want to hold yourself over for a few years try Innersound - they are relatively cheap used and compete with the big guys when used with Electrostatics quite well. They may be half or a third the price of the big guys but are at 98% or 95% at the least of the quality.

3) I'm curious about ClassD. While I love my big PassLabs ClassA amp and all that comes with it, I've heard that ClassD stinks for MartinLogan/SoundLabs but there is sometihng about the load profile of Magnepans that are different and they can be used. The reason I mention this is that you can get ridiculous amounts of power through Class D, and with the 20.1s that might be interesting.

Also - there are professional ClassD amps that I would love to compare to 'audio' amps.

Professional Class D amp:
Crown XLS 5000 in 4-Ohm Bridged Mono mode: 5,000 watts
Crown Dsi or Cts - both have 'low ohm' modes, 2,500 - 5,000 watts depending on how you hook them up.
QSC PLX2 3602, 1800 W @ 2 Ohms, 1100 at 4

Audiophile Class D amps to consider:
BelCanto REF1000 MKII: 1000W, good to 2 Ohms
(and this is a gen 3 Class D amp, and it is analog-controlled, not digital controlled, I hear that is a lot better, and they've figured a lot out since gen 1)

Rotel RB-1091 - 1000W at 4 Ohms. Rotel with a 20.1? Hereasay? Could be, but still - this could hold you over for a few years, and you'd be playing with 1,000 watts! I'd go with the BelCanto, but as a holdover amp, this would be 'fun'.

Personally, I'd just get the largest Pass XA.5 that I could afford, or 4 of them with active bi-amping via Marchand or Bryston. If you have money leaking out of your wallet, get the Pass Labs crossover, it has no competition.

Maybe head towards bi-amping right away. Then something like the Rotel isn't so crazy, as monoblocks you need 4 and if these are 10k each, that is a lot of cash. Then you can dial in the crossover for a while, then upgrade the amps - and anyhow it sounds like peopel spend a lot of time getting bi-amping right and the Rotel's would hold you over during that period.

If you have the room in your house and the inclination, go for 20.1 vs 3.6. Push pull is definitely different. However, if you are money constrained (many 20.1 owners just aren't) one could argue that 3.6s with the difference in cost applied to amplification, would ultimately sound better.

Mcintosh is your best bet. The sound is warm and powerful, the build quality is outstanding, and the resale value is the best around. Audio Classics currently has NOS MC352's in stock for half the cost of a MC402. I would put one one each speaker especially if you go for the 20.1's. They have the same fully balanced push pull amplifier design as the MC402's and would provide 700 watt at 4 ohms per amp. I have MG1.6QR's and I have one MC352 powering them; it is a fantastic combination. I had an Audio Research VS110 powering them for a while, which was amazing, but the cost of re-tubing forced me to sell it. The sound will be different from what you are accustomed. Audio Research and McIntosh have very different characteristics, but after you listen for a while, I am sure you will find the change to be more a swapping of benefits rather then a disappointment. If, for some reason, you are against Mcintosh then Bryston would be my next choice. I have heard Pass amps, and I love them given they are mated with a suitable speaker, but the Magnepan is slightly too revealing which could create a fatiguing experience. Bryston makes fantastic components and would work well with the Maggie's, although, after hearing both combinations, I still prefer the McIntosh setup as its warmth matched with the Magnepans accuracy, combines for an extremely realistic and pleasant experience.

>>08-24-09: Lece
>>but the Magnepan is slightly too revealing<<

There is no such characteristic as "too revealing".

I am running 3.6 Maggies and have finally settled on McIntosh 501s as my amp. The Audio Research 150.2 did not have the power need to drive 3.6s and rather than go to 300.2 I decided to give McIntosh a try.

The thing about McIntosh is that if you dont like them, you can get almost all your money back on Audiogon. I did buy used 501s and at a little over 50 percent of list price they are a great buy.

FYI, in both cases I mated the amps with a tube preamp by the same manufacturer. The synergy seems to be worth it to me, but as I always say, let YOUR ears make the decision, not what we say.

Of the amps you have listed, I would go with Bryston or Pass. I really like Bryston amps and I have heard them used with great success with Magnepan speakers. WRT the Audio Research HD220, although that is a great amp (I auditioned it before choosing the Luxman MQ-88), I found the fan noise to be an unacceptable audible distraction during soft music passages.