Conrad-Johnson Premier Five monoblock power amplifier
\That "everything" includes the aforementioned liabilities, very high product cost (because of the massive output transformers and high-voltage B+ storage capacitors required), and gut-busting weight in high-powered versions.
Then there's the terrible emotional price one must pay for owning a tubed component. One is constantly thinking, whenever listening, that all those warmly glowing glass bottles are in phase two of a gradual self-destructive countdown. (Phase one is the break-in period.) Eventually, they wear out and need replacement; will anyone still be selling tubes in the US when that happens, or will you have to special order them from Vladivostok? But that's not the worst of itthere's the suspicion that those aging tubes may start sounding a little "off" before they become obviously bad. Will you hear it when it starts happening? When will you hear it? Early on, so you can tell your audio friends "It doesn't sound quite as good as it did. I guess the old output bottles will need replacing soon"? Or (more likely) will it creep up on you like senility, so slowly you won't notice it at first, while all your friends whisper among themselves about how awful your system sounds? It could be worse than...body odor!! (footnote 1)
Why, then, would anyone like tubes? For the best of all possible reasons, as far as I'm concerned: because they sound good. We haven't discussed the special sound of tubes in Stereophile for well over a year, so a recap won't be out of order.
Ten years ago, even the best tubed amplifier had a uniquely characteristic sound which immediately identified it to experienced listeners. The first impression of that sound was one of warmth and forwardness. Comparing it with the sound of a good solid-state amplifier of that time, we would note that the midbass was fat and rich rather than taut, deep bass was often noticeably weak, the entire middle range and middle highs were somewhat prominent, and extreme highs tended to be soft or dull, depending on how you felt about itbut with a superbly musical delicacy, sweetness, and naturalness.
There was more: for reasons no one has satisfactorily explained to this day, tubes always seem to reproduce magnificent depth perspective in simply miked recordings. Thus, "the tube sound" was an interesting mixture of strengths and weaknesses, and how you felt about tubes depended entirely on how you felt about each of those aspects of reproduced sound quality. Like digital sound, tubed equipment has traditionally been adored or despised, with no neutral camp.
During the past 10 years, however, tubed components and solid-state components have been edging ever closer in sound. Solid state is losing its high-end bite, sizzle, and grit, along with the middle-range suckout; tubed components have been grown more neutral through the middle range (though this has been their strongest suit, anyway) and more extended and detailed at both ends of the spectrum, but without losing any of the marvelous depth presentation or high-end euphony. It is probably safe to say that the perfect amplifier, if there ever is one, will sound almost exactly midway between the best tubed and the best solid-state amplifiers. Or, to put it a little more cogently, that it will embody the strengths of both, with the weaknesses of neither.
The Conrad Johnson (footnote 2) Premier Five is a perfect example of how these differences have dwindled in recent years. I have, in fact, encounteredalthough not all in the same sampleinstances where solid-state amplifiers have actually done solid-state-type things less well than the Premier Five. They have exhibited poorer low-bass performance, more forward middle range, and less open-sounding high end than the Fives. But none was a paragon of solid-state performance. It's when the Premier Five is stacked up against state-of-the-art solid state amps that it begins to show its mettle.
We have mentioned many times in these pages that certain loudspeakers seem to do better with tubes than with transistor electronics, or vice versa. That is still true. The most recent example we found was the Infinity RS-1B, which did not begin to sound right until we tried the Premier Fives on the midrange and tweeter sections (the low end of the RS-1Bs sounded good with a variety of amplifiers). And electrostatic speakers, notably the Quad ESL-63, have generally sounded much better with tubes than with transistors, though the reverse is not all that true. Unlike most previous tubed amplifiers, which were just too fat and dull to sound right with most dynamic speakers, the Premier Fives are almostbut not quitea universal amplifier: an amp for all speakers!
There have been a number of dynamic systems with which we've used the Fives that sounded as good overall with them as with any in-house solid-state amp. The big JBL 250-Tis, for instance, sounded more natural through the whole middle range and superb at the high end. Although the high end of the Fives is slightly softer than a very good solid-state amp, and the high end of the 250-TIs more extended and natural than most any other dynamic tweeter, the combination did superbly. The Fives didn't do as much as some solid-state amps at compensating for the overly loose and ill-defined low end of the JBLs, but it's hardly a problem to be laid at C-J's doorstep. The ESB 7/06s, which received a both good and bad report (they do some things superblydynamics and tonality!), delivered a smoother-sounding high end and even greater depth and presence (realism) through the midrange, with little loss of bass performance. Some of the inexpensive speakers I've tested recently also did well with the Fives, but detailed recommendation of a $6000 amp for $400 speakers hardly seems justifiable.
However...as nearly perfect as the Five seems to be, there is still some of that tube sound. In terms of deep-bass impact and midbass control, the Five is bettered by several much less costly solid-state amplifiers. Its high end is equaledalmost duplicated, in fact by only one solid-state amplifier I know of: The Rowland Model Seven, which, at $5500/pair, is in the Five's price class but has a completely different sound. Both have as nice an extreme top as I've heard anywhere.
It's through the middle range, howeverwhere most of the music isthat the Premier Five just shines. On any speaker, that midrange just comes to life! It is forward, detailed and alive without being hard, and has a beautiful sense of depth and spaciousness. Imaging is as stable and specific as I've heard (if the speakers can match that capability). The only solid-state amplifier I've encountered that competes with that middle range is the Electron Kinetics Eagle 2, which has better bass, but not as suavely musical a high end as the Five. (On the other hand, it's a bit less than one sixth the price.)
One of the best arrangements I came up with while working with the Fives involved using them to drive the upper-range electrostatic panels of the MartinLogan Monoliths, while biamping the low end with the Eagle 2 and a Cottage Industries electronic crossover (footnote 3). Full-range, the Fives did not do as good a job of controlling the Monoliths' low end.
The Premier Five has already earned a reputation for excellence shared only by some of Audio Research's tubed units (which I have not heard). Unlike its predecessor, the gargantuan, 140-lb Premier One (two channels at 200 watts per, on a single chassis), I did not find the Five to be "best suited for electrostatics." It can hold its own with the better solid-state amps in some areas and beat them in others, and with a wide variety of speakers.
I must now admit the undeniable. These mono amplifiers are no bargain in terms of dollars per watt, or of convenience. You can buy more power for much less money in any one of a number of solid-state power amps. Most of those amps can be moved around without using a handcart. (Try dragging a loaded handcart upstairs sometime!) And none of them contain devices which will ultimately wear outnot within a short lifetime, anyway.
There is a genuine risk in handling amplifiers this heavy (not to mention the Premier One!). Unlike heavy loudspeakers, which usually end up sitting right on the floor, amplifiers are often installed off the floorin a rack, or on shelves. Frequently, this is not done just for appearance's sake; those solid, square corners can give your ankle one hell of a bruise! But stashing the amps out of ankle's way has its risks, too.
Each Premier Five has a large pair of handles at the front, which make it deceptively easy to lift the unit an inch or so off the floor. But hoisting it a foot or so above the floor involves the kind of lifting effort to which few of us flabby souls are accustomed, and the result is very likely to be a pulled back muscle or something worse. A word to the wise: Do NOT try lifting these amps above knee height without some fairly brawny help. Or, better, pay a couple of stevedores to stow the things on their shelves. Better still, let them stay on the floor, underneath something so you can't bark your shin on them.
You really have to admire what a superb amplifier like this can do, sonically, in order to to put up with the hassle of owning one. But, oh, what this does do well! This is the kind of sound that critical listeners have in mind when they use the term "musical" in a positive sense. The Premier Five is, simply, a gorgeous-sounding amp, and if you can't get this kind of sound for less money, at less weight, then so be it.
Footnote 1: Surely you jest, JGH; even rabid tube-lovers don't demonstrate these melodramatic tendencies. Have you been watching morning soap operas on your surround-sound Kloss widescreen?Larry Archibald
Footnote 2: We join our colleagues at TAS in refusing to spell "Conrad Johnson" in all lower case letters, despite the manufacturer's pleas.J. Gordon Holt
Footnote 3: Cottage Industries is the name of Threshold's kitchen-table division, where are manufactured very small quantities of low-demand specialty items.J. Gordon Holt