POSITIVE FEEDBACK ONLINE - ISSUE 28
CAD 45SE triode monoblock amplifiers
as reviewed by Sasha Matson
With a passion for audio, and what my ears hear as live performance, I have found that there is nothing to rival low-powered single-ended triode designs—for the realism that it can produce." Dennis Had.
The Amps of October
Ahh autumn ...The smell of freshly fallen leaves, the burnished oranges and golds, the scent of the last herbs of the season—the sound of a low-powered triode monoblock?! You bet. In the case of the Cary Audio Designs CAD 45SEs, these things all go together as if they were meant to be. I could reach for a wine metaphor as well. Imagine, if you will, a Premiere Cru Bordeaux, first growth—but not one of those ostentatious heavy ones. Perhaps a little lighter in color and texture, with a smooth velvety finish that keeps on sending messages about time and place, as it brings the past to life in the present moment. There you have it—that is the kind of thing that goes through my head listening to these exquisite music-makers. Makes one a bit heady actually. The CAD 45SEs are so commandingly musical and superbly subtle—at one and the same time. A special experience for grown-ups; these amplifiers are not for beginners, but rather for those who have experienced what tube amplification, especially triode single-ended amplification, is capable of. Perhaps you are that person dear reader?
Do you want to know a secret, my Positive Feedback friends? This is on deep background. In fact it may never be fully leaked to the press. This may be it! And for a select few, what my former teacher, composer John Adams would call, "the fringe of the fringe", I've got some news. Dennis Had, Cary Audio's CEO and designer, is building, by individual custom order basis, triode monoblock amplifiers based on 45-type output tubes. Dennis is designating these as the CAD 45SE model—though they are not included at this time in Cary's published product lineup. But if you call Dennis Had, and ask nicely, he might build you a pair. "I will build them by request. Selling them for $2500 for the pair—a bargain!" says Dennis. Tell him your Uncle Sasha sent you.
What It is
The CAD 45SEs have a familiar look—at least to me. That is because they are built on the same chassis as Cary Audio's CAD 300SE triode monoblocks—the first Cary amplifiers I owned. This latter model is still currently in production, and utilizes 300B tubes for output, putting out a stated 15 watts or so, of lovely single-ended Class A triode juice. The CAD 45SEs, by comparison, put out "a mighty two and a half watts", according to Dennis. That's right ...2.5 mega spectacular triode single-ended zero feedback zappers!
The long narrow 'jewel box' design, should not be a problem for most home rack setups—these measure about 6" by 20" with switches and speaker taps extending slightly further. The small front panel includes just two switches: one main power; and one 'power to the plate' which acts as a standby; and two small blue indicator lights—you do need to power up and down in the correct sequence. On top of the units to one side of the transformers is a switch to choose either a 4 ohm or an 8 ohm impedance setting for your loudspeakers. Dennis comments that, "The way the amp is designed, the 8 ohm output position is for speakers that are from 8 ohms to 16 ohms. The 4 ohm position is for loudspeakers in the 3 ohm to 8 ohm range. Let your ears be the judge. The lowest distortion output will be into a 7 ohm loudspeaker load in the 4 ohm switch position." On the rear panel are a pair of high-quality gold-plated binding posts, AC power jack, a main power fuse, and an RCA input. End of story—a clean and elegant layout, with the tubes to the front of the units and transformers and capacitors to the rear. Bear in mind that the tubes are exposed (if you have small children or pets who like to chew on electronics in the vicinity). I asked Dennis to describe a few more features of the design, and he answered that, "In addition to the special output and power transformers, there is a separate transformer for the filaments of the 5U4 rectifier tube. Along with that is a Pi-network with a filter choke which is part of the high-voltage DC supply that provides very low ripple. All the filaments are DC." Dennis Had also notes that in order to attain full output from these amplifiers, preamps need to be able to generate 2.5 volts. In other words, passive line devices are not really going to work in this context; quiet, high-quality preamplification is necessary. Naturally, all Cary Audio pre-amps meet this standard, as do many other high-end products.
The CAD 45SEs achieve their Mission Accomplished audio goals, by employing a pair of 6SN7 tubes for input, a 5U4 Rectifier tube, (in the pair I received made by Sovtek), and the heart of the matter—45 Mesh Plate output tubes, one per unit. The handsome 45 tubes that Dennis has chosen, are made by the Sophia company, in Eastern Europe. Assuming they are well made, and they look to be, these should last practically forever, running as they do with a whopping 2.5-watts of power. As for the sound of these Sophias? Out of this world!
Some Nice 'Valves' - 6SN7 Inputs, 45 Mesh Plate Output, 5U4 Rectifier
Dennis explains the lowdown on currently available triode tubes:
"First of all, the directly heated triode is far more linear than other audio tubes that one can use. In the realm of directly heated triodes, your choices are limited in terms of power ranges. From 2.5-watts (from a 45 type), to the 2A3, from which you can get, depending on the circuit, from 4 to 4.5-watts. Then the next step would be a 300B—then you are up to from 9 to 14 or 15-watts. The next jump would be to an 845 or 211 type, but you are still in the range of moderate power."
It is only relatively recently that high-end designers have had the option of working with new 45 type tubes as opposed to New Old Stock. The 45 tube design originated in the 1930s, but fell off the charts as demand grew for higher-powered tubes. Dennis Had remembers that "the only time I had fooled around with 45s was when I was a kid, with Philco table radios. The early Philcos used a 45 in a single-ended output configuration. If you listen to one of those Philco radios today, it is very rich sounding ...There was no way I could put out a product with only NOS tubes, so lo and behold I noticed that Sophia has a 45 tube—and a number of other manufacturers are coming out with 45 tubes. Really, in the past year and a half there is a supply." Tube availability should not be a problem going forward, what with China getting into the tube act in a big way, as well as manufacturers in Eastern Europe.
The Customer Is King
So, because one can do something, should it then be done? It is in the nature of designer/inventors like Dennis Had, and others engaged in high-end music audio exploration, to continue to push envelopes. But sometimes even the pushing can come from various constituents- just like it's supposed to work in Washington D.C.! I asked Dennis Had how he had got going with the design of these low-powered critters, and Dennis is willing to give credit where it is due:
"How this came about was, a customer in Washington D.C. had been emailing me, calling me, begging me, to build him a pair of 45s on the same chassis as the CAD 300SEs. Knowing that it needed a completely different output transformer, a different power transformer—I wasn't really excited. But he persisted, and persisted! Finally I said, "All right, here's what I'll do." I told this customer I didn't even have any 45 tubes. He said, 'I'll send you some.' So he sent the tubes, and because I had made a commitment I figured I had better go ahead. So I ordered some transformers, wound to the specs that I felt it should be, and proceeded to put one together. I took the pair home after I had fired them up and was getting a mighty 2.5 watts out of it. My wife and I started listening on a Friday evening, on my big Dynaudio C-4s. My jaw just dropped, and Donna looked over and said, "I think this must be the best that I've ever heard!"
One CAD-45SE = One Tibetan Spaniel? (Size-wise...)
Having been lucky enough to have spent several months with these amps, I am here to tell you that I have also heard the magic that Dennis Had and his wife heard. There is a striking musical aesthetic end-result that is achieved by this low-powered triode design. I suggested to Dennis, that the inherent given fact of a circuit and hardware which amplifies an input signal only minimally, has to have something to do with this, and he agreed ..."That is right, in terms of linearity; it is more linear. There is no question about it. These amps have that flavor of pure analog. You can hear it. It is immediate."
Speaker When Spoken To
In a perfect world, all loudspeakers would have the high efficiency numbers that would make them capable of being driven to satisfactory results with 2.5 watts. But we all know that isn't the case. But it is MORE the case in recent years than it used to be; there are a lot more options out there in terms of high-quality loudspeaker designs that are an appropriate match for low-powered amplification than there were just a few years ago. Dennis agrees: "Yes, a decade ago or more, the trend was to even lower and lower efficiency speakers- there certainly are many more choices today."
I asked Dennis Had to peg an appropriate loudspeaker sensitivity figure which will match well with the CAD 45-SEs. Dennis responded, "I would say a minimum of 92dB sensitivity—preferably in the range of 95dB and up. I would mention that the CAD 45SEs coupled with the new Klipsch La Scala model is a serious audio presentation. (See Sam Tellig's recent review of these loudspeakers in the November issue of Stereophile, those speakers are rated at a sensitivity of 105dB.) Dennis continued commenting that "The need for higher powered amplification is dictated by loudspeakers that are in need of considerably more power. Most loudspeakers are in need of more power than 2.5-watts. But I keep coming back to the fact that within its power range, you just can't touch the sonic presentation of lower wattage designs ...We (Cary Audio) do have our 500-watt designs!"
I have noticed how extraordinarily quiet these amplifiers are. Turned on and powered to average listening levels, I could barely hear their presence with my ear right on the speakers. When I mentioned this as a plus to Dennis, he commented that, "It's how I designed this particular amp- how the parts are laid out inside—using all DC current. I did that because it is imperative that you do this if you are working with 95 to 100dB sensitive loudspeakers." Just make sure you mate the CAD 45SEs with a preamp that does not have to be over-driven, and thus might start adding noise at the preamplification stage.
To Cherry Valley We Go
Given that loudspeaker sensitivity is actually a real-world matter that anyone getting into these amplifiers, or similar designs, has to pay attention to, I felt that I wanted to hear the CAD 45SEs played through a genuinely high-efficiency loudspeaker. My current reference speakers, the wonderful PMC FB1+, are rated as a 90dB sensitivity design. (read the PMC review here)
By today's standards the PMC's 90dB rating is not a particularly high-efficiency number, it is on the low end, as specified by Dennis Had. So who ya gonna call? Well, here in up-state New York, 15 miles or so from my Village of Cooperstown, is the even smaller hamlet of Cherry Valley, where my buddy Art Dudley, Stereophile Editor-At-Large, resides on his ridge-top with his beloved Lowthers. Art describes these loudspeakers (he built the cabinets himself) as in the 102 to 104dB range, with a 14 ohm impedance. I have heard them before, but only briefly. So I brought the CAD 45SEs over, and after plugging them in, compared them to Art's beloved (Art has many beloveds) Fi 2A3 stereo amplifier—as the name implies it utilizes 2A3 tubes for output. Appropriately enough as it turned out, the Fi amp puts out around 2.5-watts output—virtually identical to the Carys'.
Art Dudley and S.M. Sittin' On a Bench, In Art's Listening Room
I asked Art what he values most about his Lowthers, and he said without hesitation, their "incredible immediacy". Yes, they do start to fall off drastically around 50Hz or so, but who's keeping score? That fall-off is produced so subtly that it does give the perception of more depth on the low-end than is actually there. And isn't high-end audio the art of illusion after all? We want to create some music from nothing but some wires and a bit of juice! First of all, I should note that with this kind of loudspeaker, the CAD45 SEs had no problems in terms of producing suitable output levels. We were listening with a Lamm preamp, and though I don't know where Art's levels usually reside, the knobs were in what I consider to be a normal range for most preamps for average listening levels, i.e. 9:30 to 10:00 on the dial. Also interestingly, though the CAD 45SEs and Art's Fi amp are both similarly rated in terms of watts of output, there was more dB output in the room from the Fi. It wasn't a big deal, but that was the case. More importantly however, in my book the 45SEs were dead quiet in Art's system, whereas his Fi amp was producing noticeable amounts of hum. Differences between utilization of AC versus DC in the designs is the likeliest explanation.
Art Dudley Ponders Some Amplifiers
Notes from Art Dudley's listening room, with Lowther loudspeakers...
Mahler, Symphony #5 Tilson Thomas SACD (Hybrid disc release)
The latest in the extraordinary Mahler cycle that the San Francisco Symphony has been at for the past couple of years sounded truly marvelous, switching between Art's Fi amp, and the CAD 45SEs. As noted above, the Carys exhibited slightly less gain, but it was close enough that this is not a problem in terms of the end-results. Movement 4, the famous Adagietto, was gorgeous with a subtle low-end frequency content produced by Art's Fi. We both heard some very low-level information from the softest of bass drum taps; the Tilson Thomas recordings practically redefine what is possible in orchestral recordings to achieve in terms of dynamic resolution. Switching amps to the CAD 45SEs, we both agreed it was a slightly 'darker' sound; a little more weight to the envelopes of the attacks, if you will. Personally, I like this presentation. A bit richer, a bit more body around the pitches than with the Fi, but with a high end that was still extremely life-like and full of air. The upper strings—both the harmonics of the pitches—and the attacks of the bows, had gobs of what I call 'the breath of life' that is so much sought after in audio—at least by me.
Dylan "Workingman's Blues" from Modern Times, Columbia LP
But what about Bob? Dylan, as everyone knows by now if you have seen him live recently, as I have twice in recent years on Doubleday Field here in Cooperstown, is packing one of the great ongoing bands of his career. They can rock hard-trust me on this. And his latest self-produced album, (released on a double LP set, by a little label called Columbia Records!), is a fine sounding affair. That gruff smoky combo of highs and lows that his voice has become, suits the CAD 45SEs to a 'T'! I heard all the necessary world-weary gravel and weight, coupled to Dylan's undefeated bite. All right there in sonically comprehensible lyrics, with nary a hint of false sibilance. And this was true when I listened at home through my PMCs—which are much less efficient, and much more of a full-range loudspeaker. In fact, they are bloody well full-range transmission-line designs. These 45SE amps live and breathe this music, and were extraordinarily successful with all kinds of vocal recordings.
Miroslov Vitous, Takes On Pasolini CD
I know, this one might be hard to find- I picked it up on a whim in Rome (Italy- not up-state New York...) last summer. Boy I'm glad I did. Miroslov Vitous has remained one of the finest jazz bassists on the planet, ever since his outings with the early incarnation of Weather Report. This disc finds him in a piano trio setting, and they all play and swing hard! Good stuff, with a very forward jazz-piano timbre—in fact the piano seemed outright hot in its upper register heard through the Lowthers, comparing with both sets of amps. When I checked with the 45SEs back at home, this seemed less pronounced, leading me to believe that Art Dudley's Lowther cabinets have a bit of a bump in the upper register.
Notes from my own system, w/Cary SLP-98 preamp, PMC FB1+ Loudspeakers
Al Green, Greatest Hits, Vol.2, Motown LP
You want to talk warm? I don't think there is any stereo in the world, no matter how cheap and awful, or how pricey and great, where this man's vocals aren't going to literally heat up the room. That's just the way he sounds, and the fine way Al Green was recorded during his best early years. I recently have promoted myself to a VPI Scoutmaster turntable in my one and only A system, so spinning vinyl has become a real pleasure lately. My notes read "warm, like a nice fire and a big snifter of funky pimp cognac" (Is that a PC metaphor?) "The music has breathed by the time it gets played—the 'nose' has opened up! Kick drum sounds like a heartbeat. Al's vocals are plaintive and present and palpable—can you say that 3x very fast?"
Stravinsky, L'Histoire Du Soldat and Others, Supraphon LP
This is an English pressing I picked up in the 70s, and I'm sorry but info is sketchy on the jacket about other details. I've always enjoyed this LP though. Very quiet and elegant approach to the music, and still a fine sounding LP. Light and nimble, as this period of Stravinsky calls for—quick on its feet. Good sense of the syncopation and rhythmic drive of this music. Wonderful solo violin bowing attacks and textures.
Shirley Horn "Solitary Moon" from You're My Thrill CD
About half the tracks on this album feature the larger group arrangements by Johnny Mandel, as did the earlier and perhaps greater album they did together "Here's To Life." But this is a really nice track with a sexy smooth sound, courtesy of the Schnee Studio and Capitol Studio A as well. My notes read "Breathy, but no over the top sibilance. Warm rich mid-range, but not chesty and congested. String flow and ooze with a totally appropriate fit. Thanks Johnny Mandel for these great arrangements! Also listened to "Sharing the Night With the Blues", this is Shirley with a small combo. Heard a "slappin'" backbeat from the drums. Great walkin' bass, and the vocal—straight on, no chaser!
Rachmaninoff - Levine, Volodos Concerto No. 3 Sony CD
Here's one of those big ones—to check for the ability of an amplifier to sort things out in a musical fashion. At least that is what I recall putting on this disc for. What I recall being most impressed by, was the amazing way in which the CAD 45SEs reproduced the sound of a concert grand. I have never heard a Steinway in my system sounding so convincingly real. There was that 'red velvet' nature to the piano pitches that I always am immediately impressed with when you hear a fine piano in a live concert setting. A really good Steinway has that - that is what they refer to when they say the 'Steinway sound.' And the 45SEs get you REAL close to that ideal fix'.
To Everything There Is a Season
The Cary Audio Designs CAD 45SE triode monoblocks are a special treat for those capable of appreciating them. On one level this is a practical matter of matching these magical music-makers to appropriate high-end gear, which will bring out their full potential in a synergistic manner. As noted above, the most important item on that list is to pair them with high-quality loudspeakers that are also efficient, at Dennis Had's recommendation of a sensitivity figure of 92dB or higher. A high-quality active preamplifier is also important in terms of potential system output and noise floors. Assuming you put these ducks in a row, (and isn't that kind of system building one of the enjoyable parts of high-end audio?), then you are in for something special in your musical life!
On the higher plane of pure musical aesthetics and listening pleasure, I would have to crank up the adjectives and metaphors yet again. I will just conclude with the tried and true: I am genuinely conflicted about sending the CAD 45SEs back to Cary Audio. The only reason I am doing so, is that by staying with my beloved CAD 805s, I retain the flexibility to not worry about loudspeaker efficiencies in the future. And writing about high-end audio gear from time to time, I need that flexibility. I can honestly say that if I were building my own personal system from scratch, I wouldn't hesitate to go down the garden path with the CAD 45SEs. They are special, unique, marvelous, fantastic, life-enhancing music re-creators! If you are fortunate enough to get your hands on a pair of these, you will know of what I speak. Dennis Had and the good people of Cary Audio are to be commended, yet again, for enriching the high-end world as we know it, and continuing to push the envelope where music, technology, and art, merge and create something of lasting, humanizing value. Sasha Matson
CAD 45SE Ttriode
Cary Audio Designs