I haven't read any of the responses. I have used my speakers with two different tube amps by Mac. I have heard the same speakers owned by others with tube and SS amps. I have bi amped my speakers with tubes, SS amps with autoformers and SS amps with out autoformers and even used different manufactured amps. But we are just going to talk Mac amps. Tube amps were series I from the 60's. The 275 has a smoother less irritating sound than the 240's running mono that I was using. Bass was about the same, mids above 1000 were more listenable. 2100's were a big disappointment. The bass was sloppy and the highs irritating used as bi-amplifiers. 2200's and 2250s. were no better. The bass bloomed and it never had that punch. Now the brand of SS amp with high damping factor fixed the bass but the midrange and highs were to cold. The MC 7200 was the perfect amps for me and my particular speakers. The bass was well controlled the mid range was smooth and the highs were defined but not irritating . The problem was where to put three of them. So when the 206 came along and now that I was tri amping it was the perfect solution. When the 207 and the MX 119 came long for HT the 206 became the rear side amps with the 207 tri- amping the L & R speakers with the 7 th channel sharing duties with the 206 spare channel. But there was a difference in sound so I added another 207. The 206 was relegated in to running remote speakers and helping with electrostatic headphones along with the 2505. Now my speakers are a special case. The woofers like high damping factors the mid/tweeter combo not so much and neither do the super tweeters. So the mid range damping factor works perfect well for me. I am not saying Mac amps with autoformers are bad the just don't interface with my speakers that well.
Now let me digress. My speakers with the original passive crossover, were good with 275's running mono and a little better when Bi amping. But with the passive crossover in place and using a pair of MC 3500's my speakers became a different animal altogether. With the amp putting out 35 watts indicated you could feel a punch and a vitality I never experienced gain. Yes the high were not as good as the tri amped system with the added super tweeters, but the sound was so real and inviting and distortion free you could listen for hours. The bass didn't have the reach and accuracy of the try-amped version with the 207, but the bass with LP records was great, Its all we had. If I have one regret. is I didn't buy 4 3500's when I had the chance and bi=amped. Running 4 woofers in parallel really makes a difference. A 3500, 7200 and 207's can do that. I equalized my system. always have and that will reduce the bloom of the Mac amps with low damping factor autoformers. The 2100's 2200's 2250's 7300's etc. What my speakers would sound like with the quad based amps I I have no clue. What I do with 3 303's or 5 302's or 9 301's I have no answer for. I know with other speakers of renowned I have tried I prefer the 1201 and 1.2k, they are special. I have had little 275's outperform 2301's and 601's. The Lower damping factor of the 275 allowed the Magico speakers to warm or bloom a bit in the bass, where a Magico can be awfully dry.
So which Mac is best for you. It totally depends on the speakers you choose. maybe you want a 275 with the tube bloom some people call it to warm up the bass and midrange with an overly dry sound. Maybe you want a MC 7200 with a higher damping factor to control woofers and react with less interference by the crossover. Or maybe you want an amplifier with middle factor, like the quad balanced amps for the black background capability and better control with the damping factors round 50. The new amps with autoformers are much better than the old 2000 series from the 70's or the 7000 series from the 80's. They provide extra current and can handle a much broader window of impedance variations. Of course the champs are still the 3500 and the 7200. The 7200 could drive loads with tremendous out put to 1.6 ohms putting out over 700 watts. The 3500 which put out 500 watts before clipping and with all the output taps could drive loads from 1 ohm to 140 volt distribution lines.
Now if you own speakers with controlled impedance load and critical damped woofers like the ML series or the early XR series, then the damping factor difference will not make that much difference. You will truly hear the amps for what they are. All Macs will sound pretty much the same in the bass and midrange. But the newer quad amps with the new outputs will have a clarity and lack of induced hearing fatigue you might hear from the older amp. I am not saying you will but you might.
Lets say I found a pair of XR 290's. Would I stick with a 207 channel for each. speaker or would I start trying other amps. Probably. Starting with the 1201 or maybe a 501, if I had the money maybe a 452, It would fit in place of a 207. But there isn't a matching center channel so that will never happen. If I could afford a SCC, two S7's and and 4 A3, $140,000 & I would need 3 601's. But I don't like the 601 with Magico speakers. Three Mc 3500's would be the answer. What is the chance in that? So we all have choice to make. Always pick your speakers first. Then you can choose amplifiers. But keep in mind not to buy to little power, that can get you into big trouble.
