New amp - Conrad Johnson MF-2550 and SE version ....

From tubes to solid state.
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joeinid
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New amp - Conrad Johnson MF-2550 and SE version ....

Post by joeinid »

conrad-johnson MF2550SE
Premium Solid State Amplifier

conrad johnson MF-2550SE Solid State Stereo Power Amplifier--Bill Conrad calls this the "best solid-state amp" cj has ever built.

Bill Conrad and Lew Johnson have put their significent talents into a new solid-state amp and this is the result. Fast, dynamic and transparent are the typical solid-state strengths that we've come to expect from cj's amps...What we didn't expect was the level of harmonic coherence, something that we always expect in cj tube amps, to be so present in this new amp.

Take the stunning performance of the MF2250 and add ultrapremium parts such as Dale and Vishay resistors as well as a liberal sprinking of cj's proprietary, state-of-the-art Teflon capacitors and you have cj's best solid state amp...ever...the MF2550SE

Power:

250 watts per channel RMS both channels driven into 8 ohms
from 20Hz to 20 kHz at no more than 1% total harmonic
distortion or intermodulation distortion.
Sensitivity:
2 V rms to rated power
Frequency Response:
20Hz to 20 kHz +0/-.3 dB
Hum and Noise:
100 dB below rated power output
Phase:
Phase correct
Input Impedance:
100 kOhms
Attachments
MF_2550_Silo.jpg
MF_2550_Silo.jpg (40.67 KiB) Viewed 8768 times
mf2550seinnards.jpg
mf2550seinnards.jpg (88.29 KiB) Viewed 8767 times
joeinid
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by joeinid »

I never thought Conrad Johnson would ever come out with a new SS amp. I am very excited to learn more about this beauty. Anyone hear it yet?
jeffreybehr
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by jeffreybehr »

Hi Joe! Still enjoying the Pr. 350?

The board layout looks a LOT like that of my McCormack amps. Same distributed power-supply capacitors, same emitter resistors, same 30uF c-j 'propylene NFB-coupling caps, same Sprague orangedrop caps paralleling the PS-rail fuses, same location for the power transformer and initial PS filter caps, same speakercable.

I wonder if it's fully complementary/push-pull?

And it's NOT on their site. Where's you get that?
Tin-eared audiofool, large-scale-Classical-music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by joeinid »

Hi Jeffrey,

It's great to see you again. I appreciate your input. I sold the Premier 350. While I enjoyed the amp, there was a certain aggressive energy in the sound that I could not get used to hearing. It was kind of like trying to drive a high performance race car around town. Apparently Spearit Sound seems to be getting the amp first. CJ is usually very slow to update their website. Spearit put an ad up for it on audiogon and it's on their website.

http://www.spearitsound.com/Stereo_Ampl ... rettyPhoto
http://app.audiogon.com/listings/solid- ... iers-01060
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by Good Dog Jocko »

I have an original MF-2250, and one thing I seem to remember from when I had the cover off was that I counted a lot more C-J film caps than this MF-2550 unit seems to be sporting. From 2001 until now, I have NOT felt the need to upgrade. However, that is seen as a TERRIBLE sin in High End Audio.....as well as just about everywhere else.....so maybe I should nominate my MF-2250 as the poster child from High End Hell.....as far as audio gear manufacturers are concerned. Planned obsolesence has been the hallmark of western civilization economies ever since Edward Bernays got into the advertising act.

Some (if not a significant portion) of the C-J gear seems to go against this planned obsolescence philosophy. I noticed that when the first C-J Premier model amp comes up for sale, it is gone in a few days. I remember Bascom King saying in Audio Magazine that it was his personal favorite in actual listening no matter how well anything else out there measured on test instruments. Let's just hope the MF-2550 follows in the Premier 1 steps.
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by jeffreybehr »

If ever I were in the market for a stereo hi-power amp, I believe I'd buy the ET250s...

http://www.conradjohnson.com/It_just_so ... et150.html

http://www.spearitsound.com/product.cgi ... roduct=743

...but that's probably because I LOVE the sounds of vacuumtubes. As it is, I hope to the have the 5-channel version of these hybrid amps, the MET150, by the end of the year, replacing my McCormack DNA-HT5.

FWIW, I've sold my Vandersteen 5As and much-improved McC DNA-750s and am back to SETs, this time flea-powered* Coincident Frankenstein IIs.
Image

I hope to have 97dB-sensitive Serenity Super-7s...

http://serenityacoustics.com/products/thesuper7.html

...on hand by the end of this weekend.

* My definition of 'flea-powered' is an amp with single-digit Watts. The Franks are 300B-based 8-Watt monoamps. Temporarily, I'm driving the 5As with them and am astonished at how loudly and cleanly that combination plays.
:mrgreen:
Last edited by jeffreybehr on Sun Feb 23, 2014 7:33 pm, edited 1 time in total.
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by admin »

These look absolutely gorgeous. I don't regret having my Magnepan 20.1's, but having a very low sensitivity of 85 db makes them very hard to drive. It pretty much knocks out all these wonderful low wattage tube amps that sound really great with efficient speakers. Once again, very nice.
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by Good Dog Jocko »

The low powered amps from David Berning may still be available where he gets rid of the output transformer but still gives relatively low output impedance. When his patents run out, his design will probably be the way any modern tube amp will be produced. His tube amps are often lighter in weight than a comparable solid state design. Right now, his prices are far too high to get much of a user base in place, and you don't often see any of his later OTL designs up for sale. They always get rave reviews when they are reviewed, which is seldom. Those who want the best and can afford it will search them out, so not much need of a dealer base and lots of media coverage, as they are all hand built and most likely you place an order and wait......just like the very best connoisseur items have generally been made from custom furniture to custom musical instruments to custom tailored clothing.

Like I said, David Berning's production is too low to get any major attention by the mainstream audio press as advertising dollars will NOT be coming forthwith from a favorable review. I think that those who buy his amps probably do so because they want to stop playing around with the "flavor of the month" audiophile amp and just get into a musicophile mood and leave the gear nut plaything world behind. My music gear purchases often serve me for decades, not months or years, so I therefore have an interest in David Berning's designs, but just don't have the economic resources to make that leap.
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by joeinid »

Hi Jeffery,

I'd love an update on you new speakers. someone else recommended them to me and like to see a photo too. Congratulations!
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by jeffreybehr »

joeinid wrote:Hi Jeffrey,

I'd love an update on you new speakers. someone else recommended them to me and like to see a photo too. Congratulations!
TY. And here they be.

Early and messy.
Image

Image

Image

Moved them about 6" farther from the (currently disconnected, and I don't miss them!) SuperSubs and closer to the listener.
Image

They sound VERY good overall. I'm astonished at the bass power, extension, and naturalness. The bass HAS to be equalized substantially due to its unbaffledness, and yet the bass exhibits no hint of running out of power.
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by admin »

Looks really cool. Very impressive. Remind me, what are the speakers?
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Main stereo: ART Amplifier and ET7s2. 2nd stereo: PV-14L and MV-55. Previously Owned: PF2 preamp, Evolution 2000 Amp, PV-12AL preamp, D/A-2b Vacuum-Tube Digital Processor.
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Re: New amp - Conrad Johnson MF-2550 and SE version ....

Post by jeffreybehr »

admin wrote:Looks really cool. Very impressive. Remind me, what are the speakers?
Serenity Super-7s.

http://serenityacoustics.com/products/thesuper7.html
Tin-eared audiofool, large-scale-Classical-music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
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