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Jadis SE300B monoblock amplifier
I've never written a love story before, but then, there's always a first time. This romance concerns the stunningly anthropomorhic Jadis Eurythmie II (mostly) horn speakers and the petite, jewel-like and vivacious Jadis SE300B amps—a 10W single-ended triode design with paralleled output tubes. Kathleen and I, having flung ourselves into single-ended's embrace, have become, to some fashion, quite experienced. I've described the purity of presentation available with the Wavelength Audio Cardinal XS monoblocks when coupled with the Swiss-made Reference 3A Royal Master Controls in these pages (January '96). Using the Eurythmie speakers, which supplanted the 3As in our system, we've listened to Gordon Rankin's Wavelength Cardinal XS monos, the Kondo-san Audio Note Kasai parallel 300B stereo amplifier (next SE review to come), the ebullient and eager-to-please Cary 301SE 300B stereo unit, and the Jadis single-ended triodes, as well as our reference Jadis JA200s (yes, Jadis also does push-pull).
And we evaluated a cornucopia of 300B tubes which were slipped into the waiting sockets of these amps: the VAIC VV30B and the less-costly VV300B; the long-anticipated and very suave Western Electric 300B (see my interview with Westrex's Charles Whitener elsewhere in this issue); Chinese Golden Dragon 300B Supers; the not-quite-ready-for-prime-time ESTi 4300BLX; Audio Note-branded 300Bs (carbon-plate ESTi, I'm told). (For the hoopy-scoopy on these tubes, see my "Brace of Bs" sidebar). At this point, even Jimi Hendrix would consider us experienced—if not quite in a Purple Haze. Most of the time.
The Jadis SE300B: the Long View
This amplifier is drop-dead gorgeous. Working front to back on the elegant nonmagnetic highly polished stainless-steel chassis, you'll find an On/Off switch on the front apron with a green LED signaling "power on." There's no provision for warmup/standby mode as with Jadis's larger amps. Topside, there's an oozing-with-casual-quality power transformer, somewhat more diminutive in size than the lump of a hand-wound thing that crouches darkly on the chassis of the JA200s. That's followed by a pair of 5R4 rectifier tubes, a pair of caps, and the elegant Jadis signature square black potted output transformer with its elegant gold top-plate. Behind are "ignited" the two 300Bs, and a single 6SN7 at center chassis rear, flanked by another pair of caps. On the rear apron, there's an IEC power cord socket, an input RCA jack, and a single pair of binding posts.
Jadis SE300B: the Technical View
I'll quote from a spec sheet on the Jadis parallel single-ended triode amplifiers prepared by Jean-Paul Caffi. I haven't paraphrased his words very much, as I found the charm and humor inherent in his Technical Franglais to be without peer in communicating the concepts behind them.
"The SE300B supplies a power of 10W RMS and functions in pure class-A with single-ended mounting (the two tubes are in parallel) with an automatic bias [(footnote 1)]. The two high voltages, driver and power, have vacuum-tube power supplies. The bandwidth (at –3dB) is from 20Hz to 20kHz, without any feedback. The driver stage, powered at 400V, is built around a double-triode 6SN7. The two elements of the tube are mounted in cascade. The output stage is powered at 320V, which allows the tubes to work in the best conditions. The filament voltage is very finely regulated. Like other Jadis units, the output transformers are handcrafted without any gap in the magnetic circuits, and are used well below their full possibilities (they can be employed on 250W amplifiers.) It is important to have a large output transformer because a direct current crosses the primary in this construction, while in a push-pull construction, the direct current in the transformer primary cancels itself out."
I couldn't have said it myself, isn't it so? And before I cancel myself out, how about let's getting to the sound!
Tube matters
The Jadis amplifiers were delivered with a quartet of matched ESTi 4300BLX tubes (evidently from the same Chinese factory that churns out the Golden Dragon BLX.) In addition, there were a quartet of JAN 5R4WGY rectifier tubes from Chatham Electronics, made in the ol' U.S. of A. (These were egg-cup style 5R4s, with a large solid base that extended up part of the way around the glass envelope.) JAN stands for Joint Army Navy, by the way. In addition, there were two input 6SN7s not marked for origin or brand name.
A surprise package arrived soon after from what must be the nicest guy in audio, Wavelength's Gordon Rankin. "I thought I'd send you input and rectifier tubes that'll work well in the Jadis," he explained. Now I smell teen spirit! A public merci, Gordon. (As J-P Caffi seemed quite willing for me to try other tubes in his amps, I felt it very apropos to do so.) Gordon had sent a pair of his favored Sylvania 6SN7s, along with Tung-Sols, NOS (New Old Stock) red-base GEs, Golden Dragon 6SN7GTs, and very unusual looking 6SN7GTYs from the British Valve Electronic Company, whose glass-bottle interiors were coated in black.
I tried all the input tubes with some interesting results. Gordon pointed out to me that the relationship between the input tube, the capacitors used in a particular design, and the output tube affects the sound in significant ways. Keep that in mind—the following description reveals the sound of these tubes in the Jadis' circuit.
As I have always found with Golden Dragons of whatever type, they were exciting, dynamic, but slightly bleached and white-sounding throughout the frequency range. They proved fatiguing over the long haul—just too thin in the end. The Tung-Sols were a pleasant taste o' Olde Tyme Tube Sound, much lushfullness, not terribly transparent, and not very dynamic or extended. The Sylvanias, which I expected from Gordon's experience to sound the best, didn't. They were indeed wide-band and vivid, extended, clear, and spatial, and did great bass, but they proved a shade uninvolving and "hi-fi" like. They sounded a little too clean—music seemed robbed of its emotional content.
The input tube that really floated my boat was the NOS GEs. "Yup, these are the ones!" exclaimed an excited Ben Lichtenstein, an audio-crazy of our acquaintance who had come over to listen to the system. He can hear—the GEs had just the right combination of extension, tremendous air, transparency, rich harmonic structure, and tonal color. In a word, magic. Interestingly, Gordon mentioned that the Sylvanias work much better than NOS GEs with Hovland caps, so once again, be aware that everything in-circuit can make a difference. Relax, open your ears, and have a ball.
As for the output tubes...ahhh, therein lies a tale. The ESTi 4300s went south of the border almost immediately. One pair fell way out of balance, one tube nearly burning itself up while the other sat practically dormant, its filament barely lit. Same with the other matched pair, but here the dominant tube was gassy (sputtering blue light in the bottle) and began sending spitchy high-frequency bursts through the Eurythmies. Out, out, damned spot!
I got on the horn (!) to Frank Garbie, who quickly supplied two matched pairs of brown-base Golden Dragon 300B Supers, which some feel are a better bargain than GD's more expensive black-base 4300BLXs. These worked just fine, sounding enjoyably dynamic, bold, and vivid. They created a large soundstage; had good timing, rhythmic pace, and great bass; and sounded fast. They stayed in the amplifiers until the Absolutely Fabulous Western Electric 300Bs showed up. These Ever-Suave (apologies to ManleyClan™) 300Bs became the reference output tubes for the review. (See my sidebar on 300Bs for details, and check out my interview with Western's Charles Whitener elsewhere in this issue.) As it transpired, importer Garbie has made arrangements with Western Electric, and their wonderful 300Bs will be standard kit on the Jadis SE300B. Truly, a match made in heaven.
And what of the VAIC tubes? In a somewhat comical twist of audio fate, the VAIC tubes simply wouldn't fit into the Jadis amps. The tube sockets are slightly recessed, held in place by a short pair of bolts that terminate with a nut on the top chassis. The VAIC tube's glass envelope becomes very wide almost immediately above its base, and these securing nuts interfered with their seating completely. Pretty funny, if you ask me. Victor Goldstein, VAIC's importer, was somewhat crestfallen. Ex-Goldstein associate and current Jadis importer Garbie was ecstatic!
Goertz cable
We tried many different speaker cables with these little beauties, and eventually settled upon one that was perfect matched in every way—the Alpha-Core Goertz MI Ag silver ribbon cables. In conjunction with XLO throughout the rest of the system, these cables sounded above all ultra-clean and delightfully fast. You'd think a flat ribbon would be an invitation to the RFI Heebie-Jeebies, but this was absolutely not the case. Quiet, full-bodied, apparent DC-to-light extension, extreme high resolution, wonderful spatial qualities, these cables let the Jadis amplifiers be all they might. No editorializing whatsoever, aside from a certain lightness to the deep bass than could be corrected with the crossover adjustment.
Footnote 1: We're talking self-bias here, with a resistor, rather than an auto-bias circuit that requires a negative supply.
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Source : stereophile[dot]com
Jadis Eurythmie II loudspeaker
Frank had set down the Eurythmies in roughly the same position the Avalon Ascents had occupied on the 10' by 4' MDF platform (this screwed and bolted through to the floor and beams below). This left the Eurythmies in the familiar nearfield listening position. We powered them with our Jadis JA200s at first, as we were all still waiting for the single-ended Jadis SE300Bs to appear. Frank had been enjoying the '200s on the Eurythmies in his Durango, Colorado listening room, so was familiar with this pairing's voice. (The '200s are a classic push-pull class-A pentode design of approximately 130W, and our long-time reference amps.)
How practical is it to use high-powered push-pull on a horn speaker? Well, the Eurythmies are a hybrid design of sorts. The 103dB-sensitivity horn array—lower-midrange driver up inside the "butterfly" enclosure, a time-delayed tweeter sitting atop a similarly delayed upper-midrange mahogany horn—is sited above a bass cabinet enclosure containing two 96dB-sensitivity 15" woofers in an "Isobarik" arrangement. Each speaker's external crossover features a potentiometer, adjusted with a digital voltmeter, which varies the sensitivity of the horn array in relation to that of the woofers, thus optimizing the amp/speaker cable interface.
After a day or two fiddling with the crossovers, we realized we still weren't getting them to perform as best they might. Problems revolved around several points. To begin with, I heard that hootie horn coloration I dislike—saxophones sounded like they were made of wood, for example. The imaging was off—I wasn't getting the spread and depth that we've grown accustomed to. The bass wasn't very tight or well-integrated into the overall presentation, and there was a noticeable lack of dynamics.
That particular week John Atkinson was in town, and stopped by to visit. I was nearly cross-eyed from a vicious and debilitating weather-induced migraine, but managed to keep the fires lit—just. Between draughts of Veuve Cliquot, JA focused on the horn coloration, and agreed that the Eurythmies were a touch uninvolving and polite-sounding.
I'm carefully noting these anomalies to make you aware I didn't turn a blind eye to what many consider to be inherent (and terminal) problems with horns of whatever design. But it also occurred to me that, with the renewed global interest in single-ended triodes, it should come as no surprise that advances might be made across a broad front, and that some of these new designs might well succeed in vaulting over the very horns of the dilemma, especially given the advances in materials technology we enjoy today.
A welcome break
As it happens, Kathleen and I had planned a 10-day holiday around then. Like most guilt-ridden New Yorkers, I kept telling anyone who'd listen that it was our first getaway in three years. That's what everyone says. "Oh, I know, me too!" In the event, we had a heart-to-heart with importer Garbie and suggested a post-vacation rendezvous with the two French architects who'd designed the Eurythmies, and Jean-Paul Caffi of Jadis. Thirty-seven-thousand-dollar speakers do not hoot, I was sure.
I thought so, and with that, Kathleen and I bid au revoir to M. Garbie and disappeared into the wilds of Southern California to think no more of high-end audio. We began our vacation with four days of sailing with a waterlogged audio victim of our acquaintance. Nautical activities centered around a 38' racing sailboat—a Catalina. Coming from a sailing family, Kathleen loved every minute at sea, but as for me...taxi!
After several days consuming mass quantities of Dramamine, followed by (even I have to admit) a keenly enjoyable keeled-over faster-than-fast return from Catalina Island to Newport Beach, we found ourselves back on blessed terra firma. (I didn't kiss the ground, but I considered it.) We rented a total pig—a hard-steering barge of a Bonneville strayed far, far from its '60s roots. Cursing Detroit, we headed north out of L.A. for my first taste of the Pacific Coast Highway, complete with a souvenir speeding ticket. Our plans were to visit several SoCal audionuts we have the pleasure of knowing as we headed north up to Fremont near San Francisco, where liveth the Shun Mook Monks and their new Bella Voce "tuned" speaker (what else?). Five kay the pair. More Monkish speaker matters later, he said innocently...
Back in New York...
...we had but one Sunday to decompress before the French Foreign Legion showed up, shepherded by Importer Garbie and his partner at Northstar, Scott Isaacs. We read the Sunday Times, and caught up on audio gossip. Monday morning, off I went once again to the office, encouraged out the door with a smile and one of those very French shrugs accompanied by that they-all-do-it expressive-beyond-words pursing of the lips. It's usually accompanied by a slight shrug of the shoulders and a breathed-out "Ouff." I know, I know...she can handle it!
That evening when I returned, there were Frenchmen scattered everywhere in our loft. Bonjours to Jean-Paul Caffi; the Eurythmie's designer, Jean-Bernard; and his associate Jean-Phillipe; and right back to work. Everyone looked innocently around as I noted that the speakers were set even farther back in the box and fairly close to the sidewalls, finished off with a mild toe-in. I was happy to see the Jadis SE300Bs up and running, wired up with all-XLO. Digital datalinks were the fantastic new Illuminati Orchid AES/EBU, Aural Symphonics glass gooped with ioGel, and the newest Marigo Apparition Reference Signature.
The speakers' aluminum forward bottom-plates were supported on large Audiopoints set into their brass bases. The crossovers had been adjusted to 2.9 ohms, which I was informed is the Jadis amps' ideal setting. Setting the crossover is quite straightforward. The multiple Jeans played Keith Jarrett's The Köln Concert ECM 1064 (you can use any well-recorded piano) and listened for an imbalance between the right and the left hands—the treble and bass clefs. When the energy seems equally distributed, and one register doesn't overpower the other, you're there. Piece of gateaux, no?
This leads me to a Scullgression®. I spotted Robert Harley in my review of the Wavelength Cardinal XS for pronouncing the Infinity Composition speakers with their powered woofers as the way to go with single-ended triodes. I demurred, feeling that many aficionados would prefer to listen to single-ended full-range—as one can certainly do with the Eurythmies, in spectacular fashion. However, Jadis's Jean-Paul Caffi, responsible for the Eurythmies' passive crossover, will be introducing an active tubed crossover as an optional replacement sometime soon. Those chasing the final degree of musical perfection might then employ push-pull or big single-ended tubes on the bottom, such as the 211 or 845. The question is, when this further evolution of the Eurythmies' crossover is ready, will I eat my words? (A writerly punishment, no?)
In any case, with the gemlike Jadis 300Bs driven by the Jadis digital front-end (J1 Drive/JS1 Symmetrical Converter) and a JP80MC preamp, things were much improved. I checked the wood factor (tut, tut, tut...) with Saxophone Vocalise, Delos DE 3188. I always get a kick out of listening to track 2, Heiden's (no, not that one) Diversion for Alto Saxophone and Band, which sounds like it was written expressly for the Hercule Poirot series.
I don't know if you're a fan of the diminutive Belgian sleuth with the hyperactive leetle gray cells, but we love his "remarks most pointed." Listening to that track, I couldn't help but visualize Captain Hastings at the wheel of his open Lagonda, an alarmed Poirot at his side keeping his hat in place with the silver beak of his walking stick. Should you suffer from saxophone sweet-tooth, this disc will put you in insulin shock with works by Gershwin, Massenet, Bruch, and several other composers I confess I'm unfamiliar with. The recording is a lot of fun, and the horn in question is beautifully, lovingly recorded. For another check on wood (and imaging), I played "The Nearness of You" from that old favorite Trio Jeepy (Columbia CK 44199) by Branford Marsalis—my favorite thing he's done. Final verdict? No wood. (And no jokes!)
The Eurythmie II
I'll both paraphrase and quote verbatim from the Eurythmie's spec sheets. "Sculptured to reply the laws of nature, they are surprising by aesthetic in appearance. As they cannot be hidden, we have made them into works of art and have used craftsmen's techniques in their manufacture." But of course! One night after they'd first been installed, Kathleen jumped up in front of them and starting dancing sinuously. "Jon-a-ten..." (hence the J-10 moniker, get it?), "they look like hula-hula girls!" That they do, ma cherie. Keep dancing!
In a not-quite-white paper we're reminded that our brains do not actually "hear" acoustic energy; rather they analyze electrochemical data created by the movement of the eardrum. The Jadis Eurythmie speakers create these electrochemical reactions by utilizing horn transducers from 180Hz and above, which allows "30 times as much energy as a traditional speaker. By economizing on the power of the amplifiers, these systems also have the advantage of minimizing the effect of the room due to the controlled direction option." I'll presume we're talking about dispersion here.
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Source : stereophile[dot]com
