Google
 
 
 
 
   
Conrad-Johnson Premier 5
Monoblock Vacuum Tube Power Amplifiers
 


Introduced August 1984, the Premier Five vacuum-tube power amplifier was similar in design to the Premier Four, but was a mono amplifier using eight EL34 output tubes to produce 200 watts. Like the Premier Four, it featured extensive use of Conrad-Johnson's proprietary CJD polystyrene capacitors throughout the audio circuit and in the regulated power supplies for the voltage amplification stages.

The Premiere Five was noted for its delivery of high-power into complex loads while maintaining a holographic three-dimensional soundstage. Highs were unmatched in being delicate and extended.


Features:


4, 8, 16 ohm speaker taps (screw type), one input, two plate fuses, power switch, built in bias indicators.
 
 
V1: 5751
V2 & V3: 6FQ7/6CG7
V4 ­ V11: EL34
Replacement Tube Set RTPR5

As Reviewed in Stereophile Volume 7 Number 8
Anthony H. Cordesman
All tube mono power amplifier.

Power Output: 200 watts, minimum RMS, at 4, 8, or16 ohms from 30Hz to 15kHz with no more than 1% THD or IM Distortion.
Bandwidth: -3 dB at 5 Hz and 70 kHz, small signal.
Response: 20Hz to 20 kHz, +0, -.5 dB
Input Sensitivity: 1.0 volts
Hum & Noise: 96 dB below rated power
Dimensions: 20" by 19" by 9".
Weight: 81 lbs.
Serial Numbers: 530104/35.
Price: $6000 per pair.
MANUFACTURER: Conrad-Johnson Design, 1471 Pathfinder Lane, McLean, Virginia, 22101. (703) 528-8650

I cannot totally decouple my reviews of the Futterman OTL-3 and the Conrad-Johnson Premier Fives, although both deserve individual attention. Both are superb mono tube amplifiers and both are definitely luxury items at roughly $6000 a mono pair. They directly compete with the best competing tube amplifiers such as the Audio Research D-250 and D-160B (also $6000), and with more limited production items like the Berning 2100M ($2800). They also compete head-on with the best transistor amplifiers (Thresholds, Krells), and compete for the title of best power amplifier around.

I like both the Futterman and the Premier Five a great deal, just as I like the new Audio Research amplifiers and the Berning 2100M. My nod, however, goes to the Premier Fives. To my ears, they are the best power amplifier yet. In fact they are as musically exciting a power amplifier as is the new Audio Research SP-10 (modified) in the preamplifier realm. They may not have the most innovative technology, but they represent a new level of refinement in pure musicality.

Pausing briefly for the technology, each mono Premier Five provides over 200 watts into 4, 8, or 16 Ohm load. It uses all triode voltage amplifiers and eight EL-34s in an ultralinear output stage. EL-34s have proved more durable than 6550s, and are driven well below their limits. C-J estimates about 1500 hours of life per set - an estimate I lacked the time to verify with a statistically relevant sample!

The Premier Five has reasonably extended bandwidth - about 60-70 kHz, but is a classic tube power amplifier with the output transformer the Futterman rejects. The Premier Five does, however, use specially chosen proprietary capacitors and a low impedance power supply. The space and power provided by a mono chassis for each channel allow the provision of an exceptionally stiff power supply and more consistent use of polystyrene capacitors (which are significantly larger than alternatives) than previous C-J designs, but the magic is more in the execution than any fancy new circuitry. It also is in the size: each amplifier weighs 81 pounds and measures 20" by 19" by 8". Controls consist of slot-headed speaker cable terminal connection cerifiers and an extended binary power shunt control with a user adjustable analogue power protection system. (There are screw speaker terminals, an off-on switch, and fuses.)

Now for what counts - the sound. The Conrad-Johnson Premier Five power amplifiers are not all things to all men, the best in every category, or clearly above the competition. The are, however, one of those very few audio products that come in for review which emerge from record after record with the kind of sound one expects from music, and which become more impressive with each record. It is their listenability and realism in countless small details which make them outstanding. It is their overall balance or synergy which makes them worth the luxury-class price tag of $6000 per pair.

The Premier Five is not as sweet as the Futtermans. It is not quite as detailed as the Berning 2100M. It is not quite extended and flat in the highs as the Audio Research D-160B or the Berning. It cannot deliver the kind of tight control over the woofer, complex crossovers, or drive networks that you find with the Krells, nor the deep bass and upper octave extension you find with the Krells. Yet, it is the least tube-sounding amplifier that Conrad-Johnson has ever made. This may not please tubaholics that are looking for warm and syberetic sound, but it will please anyone that listens to music. It also means that the Premier Five's other virtues can shine with only a few minor areas of inferiority.

Let's take imaging. Many amplifiers have more dramatic imaging. Many etch or place the instruments more firmly, particularly in the top two octaves. Many give you a more holographic sound. The Conrad-Johnson keep exposing more detail in terms of musically natural imaging than in any other amplifier I have yet heard.

The soundstage size and depth have this same exceptional character and provide a special synergy with the placement and spread of instruments. These characteristics have to be heard with really good source material and speakers, but they make the Premiers much better than the Berning 2100M in this regard, and somewhat better than the Futtermans and Audio Researches. This superior soundstaging combines to provide the best overall soundstage I have yet heard on a very wide variety of music. This is coupled to superior dynamics.

The power handling capability of the Premier Fives (and they will go way over 200 watts) shows up in a much more effortless ability to provide musical transients and power than smaller amplifiers. It joins with the Fives; imaging power to free you from the consciousness of listening to a recorded performance which prevents you from enjoying the overall movement and activity that is essence of live music. Once again, the Premier Fives slightly outpace the Berning 2100M, Futtermans, and Audio Research in this regard.

The Fives function superbly into a wide range of loads. It is the first Conrad-Johnson amplifier that is fully comfortable with my Quad ESL-63s, with my cone speakers of the month, with some of my trick loads like the Spendors, and anything else I can borrow. They are much superior to the Futtermans in this regard and probably about equal to Bernings. The Audio Research amps also excel in compatibility, and the Krells are just a bit better than either ARC or C-J in this area. The latter superiorities, however, are minor in terms of practical impact. The key point is that the Premier Fives are considerably better than the C-J's Premier One and Four in this regard.

The Premier Fives have excellent highs. They will often be unfamiliar highs because they provide a unique blend between transistor and tube amplifier, and I must caution you that this gives them a unique character. They don't sound like "tube" or "transistor"; they sound like music.

You hear all the highs that are musically natural when the highs are present, but you hear the hardness or analytic quality of the highs when the source material has these problems. There is no comforting or enfolding warmth or sweetness that was common in both C-J's Premier One and the old Audio Research amplifiers.

Yes, the Futtermans have sweeter highs, and the new Audio Research amplifiers and the Bernings and Krells have more extended and analytic highs. I would argue, however, that the Premier Fives have highs which sound more consistently right with the vast majority of high quality source material than anything else around. Appreciating their balance is a little like appreciating the best white wines. You are seeking clarity and assessing the quality of the after-taste rather than seeking bouquet or body. The Premier Fives give you the balance of the French white wines without the sweetness or fruitiness of most German wines or the extension and lack of character of most California whites. If this comparison sounds a bit stained, the point is that the highs in the Premier Fives don't. They strike a balance of qualities in the highs that I feel will support more prolonged listening to music than any competition now available.

The midrange is the ultimate test of any piece of high-end equipment and here the Fives again have a slight but important edge. Most tube amplifiers do best in the lower and middle midrange (I can barely refrain from referring to the middle midrange as the ultimate test of audio quality; it determines whether a product is middle class! Or maybe the class of the middle - in the middle.), and show warmth in the upper midrange. The new Audio Research amplifiers and the Berning 2100Ms avoid this warmth, but are slightly dry and distant in the case of 2100Ms and vary from a bit bright to slightly hard in the case of the Audio Researches. There is a very fine line between the Bernings, CTs, and Audio Researches, but the Premier Fives seem to have it almost right.

As for bass, I would argue that the Premier Fives combine power and control with flat and extended bass to an extent that no other tube amplifier can do. Once again, this will be load dependent. A Futterman is superb with the right load. The Berning and Audio Research can "lock in" with a given speaker and outperform the Premier Fives. But, the Premier Fives are the first Conrad Johnson amplifier I have heard that worked well with every full range speaker I could find, including complex loads like the Quad ESL-63s.

They provide both power and control. Past CJs have tended to have more power than control and to vary in the lower octaves according to the load. The Fives again fail to call attention to themselves. They deliver the best bass I have yet heard from the speakers I really know well. They work superbly with the Quads, Fuseliers, Vandersteens, Thiels, and Celestion SL-600s.

Your choice may be more complex, however, if you multi-amp. I have spent a fair amount of time listening to various amplifiers on a friend's multi-amped Magneplanar Tympani IVs, and on the Infinity IRS?s at Excalibur Audio. In the process I have become aware that amplifiers change character when you shift the bass load, just as they do when you change speaker wires and interconnects. I will stick to my previous generalizations about the Premier Fives on the basis of what I have heard on these two multi-amped systems, but the Premier Fives were not quite as good with the IRS's as they were with most speakers. I?d make sure to borrow before I bought if I owned a complex multi-amp and crossover system. We are talking nuance here, and such a system can alter the balance of an amplifier in many subtle - or no so subtle - ways.

This leads me to close this review with a more general caution. I have discussed my feelings about four sets of amplifiers; the Conrad-Johnsons, the Audio Researches, the Berning 2100Ms, and the Futterman OTL-3s. I find the Premier Fives to be a truly exciting product, and I have made a personal choice in favor of them. My preference for the Premier Five, however, is based on a very fine balance of qualities that come together only after careful system adjustment, and are the result of prolonged listening.

The choice is not made on the basis of order-of-magnitude differences. I could easily live with the Berning, the Audio Researches, or the Futtermans. On some material I prefer each of these competitors, and on some days I might prefer any one of them on all material. It is a very close thing, and I cannot quite ignore the fact that the Berning 2100M is competitive in virtually all respects, and yet only (only?) cost $2700. I realize no audiophile cares about $3300 - it's the sound that counts, but?

I'd advise you, therefore, to do a lot of listening to see if your taste really matches mine. For the privilege of dropping $6000, you should be able to borrow the amps and try them on your system - or at least have a right of return. When you do try them, I can promise you will get fine sound out of the Premiers right out of the carton. I would advise you, however, to let them burn in for at least 20-30 hours, and spend a lot of time with interconnects, speaker cables, and cartridge VTA to ensure you get the very best the amplifiers can deliver (this would of course be true for the competition as well). Remember too that my preference is based on my conclusion that these amplifiers sound natural and accurate over a very wide range of material, and not on their ability to sound exciting or tube-like.

Further, I can promise you music if you buy, but not the audio equivalent of the "raid over macho Grande." If you only want today's certified best and most expensive status symbol, you should probably keep buying magazines and reading reviews ? don?t ever actually buy an amplifier. The high-end is as competitive today as it has ever been. There may be a Berning 2100N or 220 by the time this review comes out, I have been told there will be a new Krell stereo 100-watt amplifier, and a new Futterman with a regulated power supply. I'd be amazed if Bill Johnson didn?t have another improvement to his D-250 somewhere in his circuit board or back pocket.

Put your money where your taste is, and listen to the music. The Premier Fives will reward that set of values for years. They will do so long after some other amplifier has won the Rave Review of the Month Club, or provided the illusion of six more inches of apparent depth.

 


 


 
© 1997-2013 HIFISHACK. All rights reserved