Tube Power Amp Reviews

It was a tiny capacitor which failed, he told me later. It happened only on my amp. No other Defy 7 had failed and no other would fail for the same reason because the failure was Victor's fault.

Well, not really.

Here's the story. Jadis made some changes on the Defy 7—using caps to bypass the fuses for the GE 6550 output tubes. Jadis sent this particular Defy 7 to Victor without the caps installed, so Victor could hear the amp without the bypass caps. Before he gave me the amp, Victor decided to have bypass caps installed—but a miscommunication with the factory meant that the wrong value caps were put in. When a tube was stressed—as it was after playing all day—the cap failed.

Victor says this can't happen again because this was the only Defy 7 on which wrong-value caps were installed; all Defy 7s now come from the factory with the correct caps.

"What will the readers think of me? My reputation?" Victor asked. "They will think I am an idiot. I am roooined...r-r-r-rooined."

"No, you're not, Victor. People will think you're a human being. These things happen. And Murphy's Law always says that if there's going to be a failure, it will be a review sample that fails."

Sonically, I think the Jadis Defy 7 is excellent—some of the best bass I've ever heard from tubes. And physically the amp is beautiful. But it's a big beast, with three transformers all at the front of one chassis. It's a devil of a beast to move. To lift it, you have to hold it under the front of the amp where the transformers are and get your sense of balance—all the weight is in the front. If you try to pick it up at the center, the amp will get away from you. Apparently that's happened at least once.

Lewis Lipnick apparently tried a Defy 7 and found it wasn't up to driving his B&W 800s. Not surprising—those humongous speakers probably require the muscle of Krell. But I have not heard a tube amp that's better in the bass than the Jadis Defy 7. Hyperfy was right. The class-A JA-80s and JA-200s may have greater delicacy and detail—some je ne sais quoi that I feel only a class-A amp can have. I understand that Arnie Balgalvis now has two pairs of Defy 7s to drive his Apogee Divas, so I'm sure we'll be hearing more from Arnie. And Hyperfy, too—I'll keep you posted. (Do you think Hyperfy's trying to keep me from visiting?)

DO and others have said that a tube amp's sound quality is largely dependent on the transformers. Who am I to argue? The Jadis transformers are said to be hand-wound in Bordeaux wine country—a time-consuming process which involves several days' labor for each amp (you can see why the Defy 7 can't be cheap).

The first Defy 7s didn't get quite the same rave reception. I remember an early Defy 7 at Definitive Hi-Fi—I thought it was good, but not excellent. That was before the bypass caps. Apparently, the fuses were fouling up the sound of the amp. Victor says that installing the caps opens up the sound—more detail, more delicacy, more air there. And, having heard an early Defy 7, I agree. The Defy 7 certain does uphold the Jadis reputation for superb sound—sacrificing some ultimate delicacy and detail but giving tight, taut bass that, to my ears, more than makes up for it. I think that the stereo, single-block construction is the amp's biggest drawback—but then, how else are you going to get 100Wpc of Jadis sound for $5500? Surprisingly for a Jadis—incroyable!—this amp is cost-effective.

It may also be a better investment than your typical $5000 or $6000 transistor amp. No, I don't recommend that you buy hi-fi gear as an investment—unless it's an old Marantz tube amp or something, a very sought-after vintage collectible. But I don't think your Defy 7 will be obsoleted next year or the year after by a replacement model which sounds more tubelike. It can't sound more tubelike; it already is tube (footnote 3). True, you have the not-inconsiderable expense of tube replacement—this stereo amp uses twelve 6550 output tubes, but the bias on each is set relatively low (approximately 28 milliamps), so you may get two, even three to five years on a set of output tubes.

Meanwhile, I divested myself of the Spendor S100 speakers. Actually, I sent them along to Stereophile in Santa Fe so someone else could have a listen. You know me—I'd had the speakers for over a year and needed a change. Also, I'm planning to sell my house and move into smaller quarters—one reason why my reviewing activity may be curtailed in the coming months. I experimented with several loaner speakers before purchasing a pair of Celestion SL700s and a pair of Epos ES11s. My intention is to keep both, for separate systems. Now don't you go selling your Spendors—they are fine speakers!

Enter the VAC PA90s
Meanwhile, I arranged with Mike Sanders, of Quicksilver, for a pair of the new 90Wpc KT88 chrome monoblocks—the so-called "Silver Monos." There would be a delay, however. How to fill the gap? Well, the Adcoms were still on hand...and I was able to arrange a month-long audition of the Valve Amplification Company's PA90 amps—the 90Wpc mono configuration that retails for $4890/pair (footnote 4). These are the kinds of amps you can lust over.

As configured, the VACs put out 90Wpc in "ultralinear" mode and about 45Wpc in triode. The Spendors were already gone by the time the VACs arrived, so I listened mainly with the Scientific Fidelity Teslas, about which I may have more to say in future.

I wondered, as you might, whether the VAC amps might sound as good as they look. Man, these amps are gorgeous—richly painted in black, almost like a lacquer box, with brass accents. At the Wolf Man's—David Wolf's Audio Images store in New Canaan, Connecticut, which closed at the end of June, alas (footnote 5)—the VACs and the Teslas produced some of the most palpable sound I've ever heard. Such a soundstage!

Could the amps create a similar magic in my own listening room?

Yes. DO has another pair of these amps, and for longer audition, so he'll be writing them up at greater length, but I must say I was mightily impressed—especially with the amps in triode mode. They had a realism which was positively breathtaking. Talk about detail, delicacy, smoothness, and utter transparency. The Sci-Fi Tesla speakers are no slouches, either, when it comes to soundstaging.

If I hesitate about the VAC amps, it's in just one area—dynamic impact. In the triode mode especially, the amps seem to lack the last ounce of oomph. Switching to the "ultralinear" mode gave me more vigorous dynamics—at the expense of some smoothness, delicacy, and detail. Changing the East German EL34 output tubes for the new Golden Dragon EL34s improved the sound somewhat, affording greater dynamics and maybe a tad more transparency overall. I wonder what became of the old East German tube factory—a casualty of capitalism? I hope not; we need all the tube-production facilities left in the world. (Ah, East Germany. I remember the East Berlin airport—guard dogs would eat you alive if you so much as stepped out of queue (footnote 6). We must keep Communism alive or we in the "free world" will run out of tubes.)

You can see why it's possible to go crazy when reviewing tube amps. Change the tubes and you change the sound. I wonder what might happen, for instance, when the new Golden Dragon KT77 output tubes become available—these might be better still and give the amps the dynamics I found slightly lacking.

Still, my overall impression of the VAC amps is very positive. These are amps of very great transparency. They have an utter see-though (hear-through?) quality, especially in the triode mode. They have an uncanny ability to locate soloists and their instruments in acoustical space—this is the "palpable presence" that I keep raving about whenever I encounter it.

How about the VACs compared to the Jadis Defy 7? Sorry, folks, I didn't have them close together enough in time to give you a definitive answer. And I changed speakers—as well as marital status—in the meantime (perhaps in that order of importance). But I'll take a tentative stab at comparing the two amps.

They are very close in overall sound quality, and not all that far apart in price. I think the Jadis amps may win out in terms of detail, while the VAC amps, in triode mode, may win out in terms of holographic realism. Close call, though. The Defy 7 definitely wins out in terms of bass impact. It would have been fun to keep the VAC amps, but the manufacturer needed them back, and who was I to argue since Stereophile already had another pair chez Dick Olsher? Besides, I had the Quickies on order.

On to the new KT88 monos
It's such a sensuous experience to unpack these amps—so beautifully packed and wrapped in tissue paper. Like the VAC amps—which come with chamois sleeves!—the Quicksilver amps are obviously labors of love (footnote 7).

Fortunately, I still had the Sci Fi speakers on loan, along with my newly arrived Epos ES11s and Celestion 700s—the so-called "special edition."

I wish I still had the Spendors to try with the new Quickies, because the Spendors had been, surprisingly, such ball-busters in the bass. Nevertheless, with the Sci Fi Teslas and the Epos and Celestion speakers, too, it became apparent that these new Quickies are different creatures from the older models.

All the good Quicksilver qualities are here: the smoothness, the detail, the holographic quality. But there's more. The power supply is beefier, and the transformers are different. These amps pack punch! I mean, man, they kick butt. (Oops—there I go again! If it's not balls, it's butts.) They have full, deep, interesting bass—and they're relatively tight and taut. I don't mean that they have tight, taut killer bass like Krell—but the bass is still excellent.

I experimented with KT88s. Kevin Hayes, of Valve Amplification, also imports the Golden Dragon Chinese tubes under the Tubes by Design marque. I purchased two matched pairs of Golden Dragon KT88s, which, to my surprise, sounded quite different from the Chinese KT88s supplied by Quicksilver, just as, say, moo shoo pork might vary from one restaurant's recipe to another's.

The Golden Dragon KT88s gave the amps even tighter, tauter bass—better integrated with the rest of the sound. Transparency improved, too—delicacy, detail, palpable presence. Sorry to keep using the same words over again, but this is what tubes are all about. When was the last time you heard someone describe a transistor amp as delicate?

To keep the Quickies? I could have sent them on to Stereophile, but I'm keeping these amps. The VAC amps may have even more in the way of transparency, but they're also more costly. Ditto the Defy 7. As the Quickies and the Celestion 700s broke in, the sound just kept getting better and better. Timbres were just right—smooth, sweet, musical.

But then—of course—disaster.

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Footnote 3: Jadis does not have a history of replacing its models with newer models. What I call the "churning" of models can drive the customers of some companies crazy and adversely affect resale values.

Footnote 4: Valve Amplification Company, Inc., 1911 North East Ave., Sarasota, FL 34234. Tel: (941) 952-9695. Web: vac-amps.com

Footnote 5: This store is not related to the store of the same name in Pennsylvania.

Footnote 6: I once took the U-Bahn line that loops through East Berlin. The sight of machine-gun–armed guards at the brightly lit but closed East Berlin stations, presumably to prevent well-fed Westerners seeking asylum from jumping from the train, sticks in my memory still.—John Atkinson

Footnote 7: Quicksilver Audio: Van Nuys, CA (1981–1985); Stockton, CA (1985–1992); Reno, NV (1992–2005) Denver, CO (2005–2008) 7475 Murray Drive, Suite 17, Stockton, CA 95210 (2008–present). Tel:(209) 957-6640. Fax:(209) 957-6641. Web: quicksilveraudio.com