McIntosh MC250

bichitus

bichitus

Active Member
Hi friends, the last weekend I bougth a McIntosh solid state power amplifier model MC 250 in an estate sale in $200. The amplifier is in very good condition and I think is beautiful (industrial shape), all parts are originals and the sound is nice, warm and very good in my little speakers AR M2. My question is I have three sets of loudspeakers:
1. Acoustic Research model AR-12
2. Acoustic Research model TSW-910A
3. Gale GS401A
and I want to know which is the most appropriate for perfomance of this amplifier.
I appreciate any suggestion and commentary about it. Thank you
 

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Very nice. :thmbsp: Let your ears be the judge. However, the MC250 only makes 50wpc, so would be easy to over-drive it if you are into listening loud.
 
Congrats on your theft of that amp! I think at normal listening levels it should be able to drive any speaker you want, but you'll of course decide what matches best. I've used mine to drive B&W 805S, Matrix 805, and Paradigm Studio/20 speakers, the former two being power hogs and still sounded great.
 
The 250 has an interesting power history, most all of them were capable of 70W+, there are service notes that make them capable of more. Don't underestimate the 50W rating, there are few speakers the MC250 would have trouble driving to at least moderate levels safely.
 
What a great find, i think everyone serious about good audio should own an mc-250. The mc-250 was designed to sound like tubes, i think the 250 sounds warmer than most tube amps, IMHO you now own the best 50 W.P.C. amp ever made.
 
theebadone said:
What a great find, i think everyone serious about good audio should own an mc-250. The mc-250 was designed to sound like tubes, i think the 250 sounds warmer than most tube amps, IMHO you now own the best 50 W.P.C. amp ever made.
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How very true. It sounds better (though some say 'different') than a Mc240 - which from extended listening completely kicks the Mc240 in the butt. The Mc2505 (metered version) is my first Mc amp - and will probably be the last one I sell, if ever.
 
It is 1 of 2 power amps I've always said everyone should have in their inventory. I bought mine new not long after introduced and only sold it last year. During the whole time until about 10 years ago it was my main amp. It was replaced only because I needed a spit more power to open up my big Bozaks. It seemed to drive every speaker I ever threw it on with no problems. I like it better than the later designs using the Power guard circuits that always seemed to limit the dynamics too often and too much.

FWIW, the other amp is the CM Labs CM35 that only put out 35watts rms and was built like the industrial tank school of design that also made the MC250 and MC2100 amps.
 
"Maggie" MMG

Just took the plunge today and bought a pair of Magneplan MMGs. I live in the Twin Cities so it was no problem to drive up to White Bear Lake and pick them up at the factory. Not so much of a plunge really - $599 and 60 days to return for refund for any reason?

I'm driving them with my MC250. The speakers are rated 4 ohms, so I hooked them up to the 4 ohm screws on the barrier strip. I see a lot of conflicting information on how much power "Maggies" need. But some of what makes the most sense always points out the differences between speaker sensitivity and power ratings.

Less power means maybe not so much SPL in Db at 10 or 12 feet, but the imaging, sound stage, transparency and clarity don't seem to mind the MC250 at all. She runs a little warmer is all - if I try to turn up. But for the acoustic music styles I listen to most, it's just dandy.

I thought I had remembered Terry talking about how under-rated the power output on the MC250 often was. Glad to find the post again. Still, I may shop now for another MC250 and run them as mono blocks. There are more benefits to that practice other than increased power, right? MC250s pop up pretty often and they are still a great value...
 
The problem with bridging the MC250 is the minimum impedence for the amp becomes 8 ohms.

I ran a MC250 as my main amp from about '69 to 2000. I would have run it until I finally sold it in 2012 except it met its match with a set of Bozak Symphonys.. My amp pushed out the high side of the 70 watt range before hitting the max guarenteed thd. I ran the 250 in my 2nd system until selling it in 2012. It is an iconic amp everyone should experience.

I located a MC2105 to replace it. It had been rebuilt by the Mc dealer here of the time and put out 145 watts before hitting max guarenteed thd. At the tike I was unwilling to give up the voicing of the 250. I listened to every Mc I could locate, new and used and not even the MC2205 was the same. The MC2105 was originally described as the MC250 just with a bigger ps and more output transistors. They sounded the same to me. You may want to look for a MC2100 that is the MC2105 sans meters, looks like a MC250 but bigger chassis.

Either way you get an extra 3 db.
 
I have to admit to having little experience with Maggies, I have repaired 4 or 5 pair of vintage models.

Two things come to mind however, they are a whole lot more efficient in the sweet spot compared to anywhere else and they seem to suffer from compressibility more than almost any other speaker design

It is not heat related like in so many pro applications, but more a function of the Mylar sheet being it's own suspension. You get to a certain point, crank in as much power as you can muster up, and they just do not seem to play louder.
 
Brian said:
"The problem with bridging the MC250 is the minimum impedence [sic] for the amp becomes 8 ohms."
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Here is a snippet is from Roger Russell's MC Amps page Part 1: http://www.roger-russell.com/amplif1.htm

MC250: "ELECTRICAL: 50w/ch stereo. 100w mono. Response 20-20kHz (+0 -0.25dB). Distortion 0.25%. Noise and hum -90dB. Output impedance 4, 8 and 16 ohms (2, 4 and 8 ohms mono). (Emphasis added). Damping factor 10. Input impedance 200k. Input sensitivity 0.5v. Sentry Monitor.

MECHANICAL: Chrome chassis. Output barrier strips. Audio inputs. Gain controls. Mono-stereo switch. AC outlet. Circuit breaker. Output socket.

Size 7-1/16"H, 10-5/8"W and 15-5/8"D. Weight 35 lb. Sold from 1967-1979. Last retail price $429.00"

Was that 8 ohm minimum bridged - something that you were able to physically measure in the amp you owned? Mr. Russell could be wrong I suppose. But it's something to wonder about.

It would be fun to have a pair of MC250s. Or, maybe a MC2505 in addition to a MC250. Love the glass face and meters, panloc and cabinet look. The mid-70s McIntosh gear had the look just right to my eye, and I suppose many of us first lusted after this gear when they were in high school - as I did - class of '77... MC2505 is the same amp behind the glass front, right? - and beautiful lined up next to a C28 and a MR77. I would not pass up a deal on a MC2100 or MC2105 either. Does anyone know, when you bridge a glass faced MC2xxx, does one of the meters take a rest?

Well enough. For now, the next money will be spent in restoration of what I have. Not only do we have the luck to have Magnepan here in town but we also have Mark Wilson's Absolute Sound Laboratories. I don't see him mentioned as much as Terry. But he is a swell guy and knows his Mcintosh.
 
A 2505 or 250 in top shape would clip around 70 to 75 watts. And when the amp came out that was a lot of power. You could tear up a Klipschorn, Altecs and JBL's, EV's with ease. Its brother the 2105 with 130 watts was a giant. The idea of 3500 was mid blowing. Only in efficient speakers like AR3 and Bose 901 could handle a 2505 and 2105. Bozak Symphonies worked well with 2505 with a 2105 you had to be careful and watch the meters. Concert Grands, bi amped worked great with 2105's . I still have my 2505 to drive my Stax headphones and remote speakers throughout the house. There is a method to get the amp to drive a 1 ohm load if you want to run a bunch of speakers throughout the house.
 
A second MC250 would be fun, an MC2300 even more so. This was a LARGE family of amplifiers that are highly revered some 40 years later.
 
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Neither the MC2505 or the MC2105 was bridgeable. I've also never been sure why this is but from looking at the schematics, it doesn't look difficult to add this feature to either.
 
Do the mc250's amps sound similar to what the ma5100 has ? I like the way the 5100 sounds better then my mc2200 .
 
dezmond76 said:
Do the mc250's amps sound similar to what the ma5100 has ? I like the way the 5100 sounds better then my mc2200 .
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The 5100 is an integrated amp, yes? I believe the 5100 predates the 250.
What are you using for a pre amp with the 2200? I find that interesting that the 5100 sounds better than the 2200. Not saying that I don't believe you...
 
I tried a c28,c24 and now I am just using the 2200 for mids and highs in a biamp setup. The speakers that I prefer the sound of the 5100 are jbl l220's.
 
seacliffe301 said:
The 5100 is an integrated amp, yes? I believe the 5100 predates the 250.
What are you using for a pre amp with the 2200? I find that interesting that the 5100 sounds better than the 2200. Not saying that I don't believe you...
Click to expand...
The 5100 does not have autoformers.
 
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