En fait , il s'agit d'une version plus récente et un peu plus puissante que le MF2500 , voici ce qu'en pense un critique américain ( en association avec un préampli CJ 18 LS ) :
" The CJ MF2500A Amplifier
The MF2500A is a 240-watt per channel amplifier that is a fairly straight-forward design. The amp is built solidly, weighs in at 60 pounds and has no handles. Great care needs to be taken when transporting. This amp has its own dedicated power cord attached to it (more on this in a moment). Also, the heat sinks are all on the left side of the amp and are a little edgy. Despite its power output the amp never got hot while driving my Martin-Logan Quests (4 ohm load) and only got warm after hammering it with movies that have made many a lesser amp verge on meltdown (Stargate, Pitch Black, Hunt for Red October, Gladiator). It has a large black power on/off switch and gold plated binding posts in the back for speaker connection. One note I should make here:
when I first connected the amp, it did hum a little. I checked all of my connections and everything was tight. Instead of experimenting with cheater plugs, which I don’t like to use, I put a Shakti Stone on top of the amp, center towards the rear. The hum went right away and all of my listening was done without a trace of hum.
Let The Listening Begin!
Every time I bring a new piece in the house, I have a habit of making sure that it is at room temperature before hooking it up and playing music through it. I do this just to ensure everything is working properly, not to do any serious music listening. Well at least I usually try not to do any listening while the equipment is still cold, but my curiosity always gets the better of me and I end up giving things a cursory listen anyway. This is usually done sometime after 11:00 at night when I find myself nodding off as I’m playing something soft. On this particular night, I followed my normal routine and started to nod a little when, all of a sudden, I was brought out of my slight slumber by the subtle nuances in the music that I hadn’t noticed hearing before. I was playing Patricia Barber’s Café Blue [Blue Note] when bassist, Michael Arnopol, started to move and breathe with a palpable presence that I had not previously experienced in my listening room. Before I knew it, it was 1:00 a.m. and I had to get some sleep. But at least I drifted off to sleep thinking about what I had just heard. I waited a few days before I listened to any more music, and a good week before I got down to serious listening. I went back to Café Blue and listened to the disc again to make sure I hadn’t been imagining things. The first thing I noticed was that the sound came from a dead-silent background. This brings me back to the power cord. I don’t know if this quiet background was the result of the fact that the power cord is hard wired to the amp or not, but I suspect it may have some positive affect. I discussed this point with a friend at CJ who told me that they put considerable effort into the power cord and felt it negated the need for an after-market cord. Cut after cut benefited from that improved quiet background.
John Coltrane’s, The Stardust Session [Prestige PCD-24056-2] was the next disc I played. There was a wide, deep stage that extended past my speakers and beyond my rear wall. Coltrane, as always, is just such a pleasure to listen to and I have yet to hear this disc in a system and not enjoy it. You’d be correct if you guessed that rendered through this CJ system, this disc was as enjoyable as I’ve ever heard it. What a great way to enjoy my favorite saxophonist of all time! He seemed to have a greater presence in my room through the CJ gear and I felt myself being drawn deeper into his performance, especially on “Don’t Take Your Love From Me” and one of my favorite renditions of “Stardust.”
While on the saxophone theme, I decided to play Gene Ammons’, Bossa Nova (Prestige OJCCD-331-2). This disc is special to me because my dad used to play it to death when I was a kid. Whenever our folks threw a card party he’d play it to death and I just hated it. But in my adult life, it is one of my favorites. Go figure. Mr. Ammons plays tenor sax with a drive and passion that I have come to appreciate. Track 2, “Ca`Purange” may be a fine vehicle for Ammons, but for me, Hank Jones’ slow, locomotive-like melody is the foundation that the rest of this track builds upon. Equally enjoyable performances come from Bucky Pizzarelli on Spanish guitar coming out of one channel and Kenny Burrell playing rhythm guitar out of the other. The sound was always musical and terms like “highs” and “deep bass” weren’t really important because everything was there. Trying to evaluate those things would do nothing but take away from the musical experience afforded by this gear. Okay, okay, for those who need to know, yes, the highs were extended and airy. Maybe not as sweet sounding as say a Klyne SK-5A or System 7, but for all intents and purposes, they were just fine. At no time did I feel I was missing any high frequency information or extension. The bass is tight and extended. It never overwhelmed the room or seemed boomy but it did have a solid grip on my ML’s woofers.
Next up was Frank Sinatra’s Sinatra Sings Great Songs from Great Britain [Reprise 9 45219-2]. Here, Sinatra is supported by an orchestra led by the great Robert Farnon. This recording is a gem, not only for the performance, but also because Sinatra, like a true professional, carried on even though his voice was not at its best. In spite of his struggles, which you can clearly hear through the CJ system, he still held it all together and turned out an enjoyable, memorable album. Listen to “If I Had You”, “A Nightingale Sang In Berkeley Square” and “London by Night”, and you’ll get a feel for just how good this album is.
To test out the CJ combo’s transient response and low-level detail reproduction, I pulled out Victor Wooten’s, “A Show of Hands” [Compass records]. Wooten is an amazing bass player and gets all kinds of sounds from his bass. He has this mind-boggling routine where he uses both hands to play the bass in a way that makes it sound as though he’s playing two basses simultaneously. He uses his long fingers to bend and stretch notes out of his bass in a manner that is unlike anything I’ve heard before. Through the CJ pieces you can hear this effect immediately. The plucking had loads of snap and detail and the sustained notes Wooten likes to play just hung there, right in the middle of my listening room before gently fading out. Wooten’s bass skills really shine through on “More Love”, “A Show of Hands”, “Medley” and “Classical Thump”.
For those of you who are really into imaging and soundstage presence, it doesn’t get much better than Norah Jones’, Come Away With Me [Blue Note]. This entire disc is wonderful and there’s not a bad or uninspiring track on it. My particular favorite is the soulful, “One Flight Down”. I just love her gospel-tinged piano playing on this track. Through the CJ, all of the performers were in their own space and spread across the stage, side to side and front to back, with each performer occupying their own space.
After a month of enjoying all kinds of music, I got the brilliant idea to pair my Thor preamp with the 2500A. All I could say was wow! I will not compare the Thor to the Premier 18 because not only is it twice as expensive, but also because the 18 works so well with the 2500A that I wouldn’t want to unfairly overstate any sonic shortcomings that may result from a direct comparison. I will say this though, as driven by the Thor, the 2500A went up another notch in detail, warmth, dynamics and musicality. The CJ amp was more than worthy of my Thor line stage and phono stage, a combination that costs nearly $14,000. A truly holographic experience to be had was when listening to John Coltrane and Johnny Hartman’s self-titled album [Impulse GR-157]. Holy Cripes! That sounded too good (fanning myself), especially the songs “Lush Life” and “You Are Too Beautiful”.
Dare To Compare
A closer comparison to the Premier 18 would be the Klyne 7LX line stage. I am a big fan of Stan Klyne’s preamps and feel they set the standard for neutrality, high-end extension and detail retrieval. I would give the Klyne the nod in the highs and in the low-end extension. The 7LX really plumbs the nether regions and if you have a system that will go below 30 cycles, you’ll see what I mean. The Premier 18 is no slouch here either. It does extremely well and will not leave you wanting. The midrange is very close and really depends on the source material. If the music you’re playing sounds natural and warm, like on most well recorded offerings from Chesky, Mapleshade or Naim, it’s a toss-up, with maybe a slight nod to the 7LX. However, you must keep in mind that all of the Klyne preamps are brutally honest and if you have a recording that’s not up to par, the 7LX will not hesitate to let you know it—and that’s with both vinyl and CD’s. It also makes system matching with a Klyne more of a task, but one you’ll be well rewarded for if you put in the time. The Premier 18 is slightly more agreeable. It’s honest and detailed as well, but will let you enjoy your less than musical recordings more so. It all comes down to personal preference as I could live with either one. Heck, it may even come down to the fact that the Premier 18 has a line of CJ amps you can easily match it with and comes with a remote. Though the preamp will work well with other amps, it sounded its best with the 2500A. The 2500A, on the other hand, is a partner strong enough to fit in a wide range of systems and budgets. It’s powerful, is as comfortable playing rock, R&Band pop as it is playing jazz and classical, and sounds good with tubes or solid state gear in front of it. The 2500A is a really flexible performer.
Conclusion
I never had a moment of trouble with either piece, the connections were always tight and solid and there were no transient spikes or pops. I know this because I did a lot of cable swapping and switching in and out of electronics. Watching movies through this system was also extremely satisfying. The amp never seemed to run out of bottom end and remained tight through some pretty demanding passages, like on “Stargate”, when Ra’s spaceship arrives and lands. That’s 5-10 minutes of an intense low-end workout that I have seen several lesser (and in some cases more expensive) amps just shut down on.
If you’re looking for a system that has all of the musical attributes most people look for, has the ability to drive just about any speaker, is well built, has a solid remote control, and won’t break the bank, you’ll be hard pressed to find a combination that’s better than the Conrad Johnson Premier 18LS and MF2500A. Highly Recommended! Specifications
Premier 18LS Solid-State Line Stage Preamplifier
Gain: 22 dB
Maximum Output: 9 vrms
Output Impedance: 200 Ohms
Distortion at 1.0 v output: less than 0.1% THD or IMD
Freq. Response: 2 Hz to more than 100 KHz
Hum and Noise: line-stage 96 dB below 2.5 V
Phase: inverts phase of all inputs at main out
Dimensions: 15.25D x 19W x 3.315H inches
Weight: 16 lbs.
Serial Number: 3401000
Price: $3,495
MF2500A Power Amplifier
Power:
250 watts per channel from 20 Hz to 20kHz at no more than 1% THD or IMD, both channels driven into 8 ohms Frequency response: 20 Hz to 20 KHz +0, -.25db
Hum and noise: more than 100 dB below rated full power output.
Input Impedance: 100K Ohms.
Dimensions: 16.375D x 19W x 6.75H inches
Weight: 58 lbs.Serial Number: 7821485
Price: $3,695
Manufacturer Address: :
Conrad-Johnson Design, Inc.
2733 Merrilee Drive
Fairfax, VA 22031
Tel: (703) 698-8581
Fax: (703) 560-5360
Web:
www.conradjohnson.com
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Créé le 18 Avr 2015 11:17
