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Mcintosh MC901

The built in adjustable crossovers are designed to cross the two amp sections over while the speaker's internal crossover is retained. The amp crossovers should be set to about 1/2 octave above or below the actual speaker's Low to Mid-High crossover frequency.
Example, if the speaker has a 350Hz crossover point the low pass should be 550 or 800 and the high pass should be 250 or 180.
This will make the two amp sections happy while maintaining the internal speaker's crossover design.

If you wanted to use an external crossover like MEN220 then you can bypass the MC901 internal crossover and send separate feeds from the external crossover.

Thanks,
Ron-C
What's the benefit of the men220 vs using the internal crossover of the 901? Don't they accomplish the same thing, or is it that the men220 Calculates what it should be? As long as the 901 stays out of the way of the speaker crossover's for the benefit of protecting the tube amplifier transformer then why is the men220 of value?

Tough to use men220 for home theater.
 
I plead ignorance on the 901’s capabilities RE: room correction, but the MEN220 is able to do room correction as well as crossover duties.

Regarding using SS on the low and tubes on the HF? My experience is that bass can be accomplished by some of the most basic amplifiers provided it is of good design and of ample power. Tubes can be a bit sloppy on the LF, if not matched well to the speakes. Some really decent amplifiers from Carver and ADCOM were produced with a lot of linear power for the money a couple of decades ago, mine rolled over from HT when six channels were no longer enough and made excellent building blocks for multi-amplifier systems. The power & current available for LF was welcome and noticable.

Of course a lot of imaging and detail makes its way into the higher regions of the LF so no junk amps.

In my experience, tubes and “tube sound” were very much at home in the midrange. Midrange and HF with smooth detail are harder to create in an amplifier and speaker than bass. I think the “warmth” that tubes create is most noticeable in voices and higher-pitch instruments.
 
Just 2.5" under a yard deep(!) I wonder what equipment furniture will be able to accommodate these for the all important visual access to the meters. I'm not convinced about the advantages of passive bi-amplification (or indeed any multi amplification except in pro applications) but a nice solution for those who are and who have the means.

Vaguely reminds me of the Altec 770A dual crossover amplifier with 30/60 watts.

altec_lansing_770a_electronic_crossover_biamplifier.jpg
Just put each one on a furniture dolly. It will still look great. No ‘equipment furniture’ necessary. LOL
Really nice unit. I like it!
 
What's the benefit of the men220 vs using the internal crossover of the 901? Don't they accomplish the same thing, or is it that the men220 Calculates what it should be? As long as the 901 stays out of the way of the speaker crossover's for the benefit of protecting the tube amplifier transformer then why is the men220 of value?

Tough to use men220 for home theater.

Please say what speakers you have. Are they designed to be bi-amped? Do the instruction mention bi-amping?
 
Yes, I am receiving the 901 soon.
The men 220 I am sure is lovely except it doesn't show you the graph. It's like a black box that does everything and you have to do all the individual testing locations. It's not a real time device that continually monitors the environment and music type which would be interesting.

So you don't get before and after graph pictures which I think is something very helpful to people. It would be nice if they extended the capabilities to work with Home theater but it's only two channel. The mystery box goes for about $5000. I know they have the same capabilities within the Macintosh processors but I don't have one of those and I don't like their processors.
 
The MC901 is for pikers!

Here's an amp: D’Agostino Relentless. Balanced, 1.5 KW monoblock, 570 lbs, $125,000 each and a meter. I recommend that you get 13 of these: 11 for your Dolby Atmos HT and two more for your patio speakers. I guess if you want to try-amp your HT speakers you'll need 35 of these.

Having just purchased a pair of 901s, I am new here, so I probably shouldn't say anything. I just can't help but comment on the amount of animus in this thread. Maybe because I am a piker.
 
That never occurred to me, but I am sure you are right. My apologies to TSmith. Still, there is a lot of envy-based criticism in this thread.
Among us Mac fans, there’s a lot of good-natured poking and—of course—envy and covetous behavior directed at one another and our purchases and obsessions. We also sometimes engage in marveling and poking some fun at McIntosh’s new and more outrageous products. (Check out, for instance, the threads on the McIntosh LB200 light box.)

Please don’t take any of it personally. I have neither the space nor (with 105dB horns) the need—let alone the funds—for a pair of 901s; but I applaud anyone who can afford and integrate them into a system. I have no doubt they are an excellent, kick-ass solution for many. (Friends of mine think my 275 is outrageous.)

Congratulations on acquiring the 901s; and welcome to AK! Please tell us about your experience with them. I’m sure many of us are curious—if not a smidge envious.
 
We all envy each other on the Mc forum.

Some have huge collections, some have meticulously maintained vintage, some one “bucket-list” systems new and vintage, some have that really cool pair of speakers, some have more time to enjoy, some have great music collections, some great music rooms for their system(s), ... I could go on. It is however almost always friendly and mutual envy, not the bad type.

What do I have? A deep appreciation for the ability to enjoy a nice afternoon now and then listening to music.

Welcome to the group, the forum, the addiction, and congrats on getting a nice pair of 901s for your system. Hopefully you’ll be back often and enjoying your music also.
 
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Please don’t take any of it personally. I have neither the space nor (with 105dB horns) the need—let alone the funds—for a pair of 901s; but I applaud anyone who can afford and integrate them into a system. I have no doubt they are an excellent, kick-ass solution for many. (Friends of mine think my 275 is outrageous.)
Well, since you asked. Edit: oops. I answered a question you didn't ask. But, since I typed it all out, and since it has relevance to equipment selection, I will leave it. I won't actually get to see my new stuff until January sometime, but I will certainly report back about that (and, if there is interest, developments in on the ongoing saga, touched upon below, of the tension between me and my wife's decorator). But fair warning to all: nothing below describes my post delivery experience with the 901s. Proceed at your peril.

In my youth, a girlfriend's father had a really great sounding stereo system. Mine was very basic, semi-homemade. I vowed to myself that someday I would have a good system. Similarly, another friend's father had a Lamborghini Muira, and I vowed to myself that someday, I would have a Ferrari. For whatever reason, I completely lost interest in sports cars, but my interest in good stereos has never died.

Over the years, I have had "decent" surround sound TV systems, that I also enjoyed for music, but never something that shocked me with sonic clarity. I have been too busy working and raising kids (and doing some other fun stuff) to really give any thought to music systems. Fast forward to the covid thing, during which I realized I could not only work from home, I could work from anywhere. So, I bought a cabin in northern Wisconsin a few years ago, and have set about decorating and furnishing it. (The indoors were 99% my wife, with my role being almost exclusively budgetary control. One thing I did was get a player piano, identical to one I have at my LA home, in traditional high gloss black.

The living room of the cabin is about 20' by 40' with a TV and stone fireplace at one end. At the other end is a mostly glass wall with a great view of the lake. In the middle is that player piano. My wife and her decorator agreed that we should plan the view end as a great place to sit and relax with a glass of wine, while looking at the lake and perhaps listening to the piano. That is when I got inspired to consider a stereo system.

I asked for advice on another site on my two greatest concerns: 1) were my ears good enough to warrant a good stereo, and 2) where is the sweet spot in terms of budget. From my other research, I was focused on a MC 352 amp, vinyl and La Scala speakers. It looked like that would cost about $30K and I wondered whether spending that much was money well spent (or might I get 95% of the benefit for 50% of the price. The advice was to go listen to stuff, which isn't easy to do, even in LA, because there aren't that many show rooms. But, that experience convinced me that tripling my budget was money well spent. My favorite listening experience was B&W 801s (but 802s were not far behind) powered by McIntosh 901's. When I heard that 901s were $19K, I swallowed hard, because that was about triple the Mac tube amp I had been considering. Then I realized that even though the amps were "dual" amps, I needed to buy two. I figured that I would save some $$$ by going with the 802s (instead of 801s), but when my wife saw the 801s, and greatly preferred their visual appearance over the La Scala's, I recognized that the price difference was easily justified by making my wife happy. The other shocker was that even though I had given up on vinyl, preferring a streamer instead, I really needed to buy a pre-amp. And, the McIntosh C12000, with its separate sections for tube and ss, was perfect. So, I put my order in for that system (901s, C12000, 801D4s (not signature series -- I have to draw the line somewhere), with a HiFi Rose 150B.

I let my wife know the good news and she had forgotten really liking the 801s. They may have looked in juxtaposition to the La Scalas, but not in isolation. And, she hadn't realized how big they were. I pointed out that they were also gloss black (like the piano) and that her decorator was sure to give it a thumbs up (if she doesn't we are shopping for a new decorator). But my wife's parting comment was "where are you going to put all of that equipment". I explained that there wouldn't be any wires running across the floor -- everything would be below the floor (that helped) but that the amps must be very close to the speakers. I wasn't prepared for her next questions "how big is the amp?" I showed here that they measure 30" x 17", and explained that they will be on the floor or maybe on stands 6" off the floor. She wasn't happy, but apparently she didn't realize that there were two amps. That didn't go over well, but I did have the presence of mind to point out that the symmetry was actually a bonus, from an interior design point of view. At this point, that seems OK, but she wants the rest of the equipment hidden in an existing cabinet at the other end of the room, as she doesn't want the view windows to be even partially blocked by a bunch of stereo equipment. She has a point there, but I hope to find a low-profile stand that can hold the 3 other pieces of equipment low enough to not interrupt any part of the view, even when we are seated. And I gave the thumbs up to the recliners she wants (they look great, but they are so wide that one cannot comfortably use both arm rests at once, and they aren't long enough for a guy of my 6' height, as my legs dangle off one end, and my head gets no support at the other. But, a small price to pay for a happy wife.

Anyway, that is my story -- thanks for asking.
 
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The MC901 is for pikers!

Here's an amp: D’Agostino Relentless. Balanced, 1.5 KW monoblock, 570 lbs, $125,000 each and a meter. I recommend that you get 13 of these: 11 for your Dolby Atmos HT and two more for your patio speakers. I guess if you want to try-amp your HT speakers you'll need 35 of these.

Having just purchased a pair of 901s, I am new here, so I probably shouldn't say anything. I just can't help but comment on the amount of animus in this thread. Maybe because I am a piker.
Sorry about that, my attempts at humor often fail.

I was (I think) making fun of the the $250k price for the D'Agostino amps. Maybe (I don't remember) someone earlier in this thread complained about the price of the MC901 so giving some perspective. I will likely never hear, let alone own, those $250K amps so I can't really give an opinion about them. But I suspect they don't sound as good (or any better than) a Mc amp and are likely less reliable. There's only so much magic that can be engineered into analog circuits regardless of how much money is thrown at it. (I would be interested in actually hearing the D'Agostino amps in my system to try to understand the price, but that not's going to happen.)

Congrats on your new MC 901 amps and new system. I've not heard the 901s either but suspect they are great sounding amps like all the Mc amps I have heard.

Looking forward to hearing how everything sounds when up and running.
 
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Sorry about that, my attempts at humor often fail.
My experience exactly. Normally, I am pretty thick skinned (and I didn't take anything personally), but in this instance a part of me is feeling duped (by myself) for having purchased equipment that my ears probably couldn't appreciate when I was much younger, let alone at this stage. Anyway, I do apologize for not recognizing your humor, but now that it is pointed out to me, I do get it.
 
Who cares if your ears can't "appreciate it"? I can't enjoy the top-speed of a 700hp McLaren, but damn it's fun to drive and look at. Enjoy the art and engineering as much as the music.
 
Considering changing the stock tubes in the MC 901 I use. Anybody have thoughts on potentially better tubes to use? eg. Preamp signal Power, all the above
 
It appears you're into solid amplifiers. Do you have any thoughts on specific mcintosh to amplifiers? I was curious about the tubes being used in these amplifiers
 
Elsie - I recommend Gold Lion reissue tubes for KT-88, 12AT7 and 12AX7A positions. There are more exotic options and I can cover those if you’d like. But the GL reissues are fine sounding tubes and still a good value.

I didn’t know much about the 901 and after a bit of research it’s really a fantastic component.

For those wanting to bi-amp or those wanting to choose between a SS amp and a tube amp, this amp has a 300 W 8 KT-88 quad balanced tube section and a 600W quad balanced 600 W SS section with a built in flexible crossover you can use or bypass.

It’s kind of the love child of an MC 611 and a MC 2301.
 
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Has it really been more than 4 years? Safe to say this one can’t grow on me.

Put it in a tall thick glass face chassis with handles, big meters and tubes on top and I could be sold.
 
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