I liked ML-2's even though they could be a little edgy, I liked them. I loved them stacked driven by a 2300. I could see owning that combination. ML-4's stacked was just to much for me. What really improved the sound for ML-2's was the 2205 and its cousin the the 2200. We all loved meters so we didn't sell 2200's to consumers. But we did a brisk business with them in commercial systems. They could drive Altec speakers way beyond the ratings with out any sign of stress. Klipsch woofers died all the time because the voice coil leads were to short or if not couldn't take the strain. So we cut the edges off Altec 16 inch woofers and replaced the Eminence Klipsch woofers. Eventually Mac discontinued 2205's and we learned to love 2255's and its cousin the 2250. A 2255 could power anything a 2300 but with so much grace. Then came the 2500 and the 2300 officially was placed to rest. The poor 2205 was one of the first amps to have power guard which I embraced upon first hearing. It allowed speakers to go beyond without fear of destruction. Lots of folks didn't like 2205's because they never got that sound some folks liked at loud levels, they just remained neutral. The highs didn't become austere and there wasn't any distortion on set that some people love at louder levels. Some folks complained when the Power Guard activated the sound changed. Duh! Yes it changed sounding like a Rock FM station. Thats what a form of compression or limiting does folks.
Todays listeners are more sophisticated and understand an occasional flash if a Power Guard light is not the worlds worst issue. If you want more and your speakers can handle it you buy a bigger amp. That is what a 452 is. A better mouse trap. It is also blessed with better semi conductors, better Autoformers, and higher quality long term components. The 7200 was the first of the Mac amps to reveal what was possible after the 2000 series amplifiers were transitioning to the 7000 series. Now not all 7000 series were a big improvement over the 2000. I didn't think a 7270 was really a big jump. The century series didn't really impress me either. MC 150, MC 300 and MC 500. But when the MC352 and 501 came along with their new circuitry, I was really impressed. Now the 452 is to the 402 as a 7200 was to a 2255. There is most definitely a difference, maybe not as radical. A 452 wont put out 3 times its rated power into 2 ohms like at 7200, but it is an improvement with most speakers. Likes its big brother the 601 there are a few out their that don't benefit from a 452. Where some folks might prefer and do prefer 2301's and I have learned to respect that. I have heard it myself with Snell and Magico speakers. Just makes me want to find a pair of 3500's for restoration. But for most folks out there a 452 is a game changing amp built on one chassis that will full fill almost everyones desires. I imagine it could do the job of a pair of 501's driving a pair of XR 290's all day. Is a 452 a 1201, no or a 1.2K no or a smaller 1.25 K well maybe. 1201s have a particular sound I really like. at 2 watt levels or 20 watt levels there is something special going on. It may not be what a 1.2k does, and I haven't heard the 1.25 to make a comment. But if Steve called me tomorrow and said I have a pair of 290's for you, and now that I'm on a fixed income,I wouldn't hesitate to buy a pre-owned 452. Sure I would prefer 1201's but where would I put them and the electrician would have to put in a new sub panel and transfer the entire entertainment system to the dedicated box. So a 452 would be my choice, too with no hesitation. Its a great amp. Will it push XRT 28's and 30's to my satisfaction, no. Did I mention 1201's? Is it to much for anything Klipsch I'd say so . Though Paul was to have said a Klipschorn can handle 500 watt peaks. Thats 132 db folks, before compression. But a pair of JBL DD67000 would be a perfect match according to JBL and me for the 452. Remember JBL uses Mcintosh patented low distortion design for their cone speakers as does a few other companies. Who would have thought back in the 60's that a MC 452 would be a middle of the line-up Mcintosh amp. We were being bowled over by the 3500. 450 watts of beautiful sound. What goes around comes around. In this case 50 years later.