Turn out the lights, and it looks like a city at Christmas. Its traditional build belies its decidedly modern sound.

Despite the deliberately retro brand name, there is nothing genuinely antique about this large tube amplifier. Look back through all the audio catalogs you may have from the 50’s through the 70’s, and you’ll be hard put to find an amplifier using single-ended 845 triode power tubes. You’ll be hard put to find any single-ended tube amplifiers at all, when it comes to that.
     “Single-ended” is of course the opposite of “push-pull,” the usual way power amplifiers -- tube or solid state -- are arranged. Push-pull has been used nearly universally for decades, and for good reason. One tube or other amplification device handles the positive half of the signal, and another, identical or complementary, handles the other half. That allows you to swing double the voltage...or four times the power! And for good measure you can cancel out some of the harmonic distortion, and thereby get not only a larger signal but also a cleaner one. Why not use it?
     But the purists have always had second thoughts. Can any two amplifier devices ever be truly identical? And if they are not, then how can the signal at the output be truly symmetrical. The answer: use a single device for the whole job. Distortion at full power will be greater (the Leyla claims “below 3%” at 20 watts), but at low level -- where most of the music takes place -- it may actually be lower. As for the limited power...well, efficient speakers are currently in fashion anyway.
     And it’s clear that the designers of this Chinese amplifier have gone to extraordinary means to obtain an output that is no more than modest. The transformers on this beast are huge, and that makes the Leyla difficult to lift even for two people. The build quality is superb, as it usually is on products from this factory. What you’ll notice first, after the black brushed front panel, is the staggered row of seven 6SN7 dual triodes. But switch the amplifier on and your eyes will be attracted to what’s back of them: the giant output tubes. They light up instantly when the switch is thrown, and you could read by them!
     The tubes are not self-biasing, but they are easy enough to set, using a small screwdriver and the front panel meter. An alternative version of the Leyla has a large digital readout instead of the analog meter, but the meter is faster to use and more in tune with the amplifier’s retro chic styling. Beyond the meter and the power switch, the front panel includes just an input selector (with four choices, one of them, strangely, labelled for MiniDisc) and the volume control. There is no tape recorder loop. Our amplifier came without its normally supplied remote, which operates a motor behind the volume control.
     You’ll note the massive sockets about the output tubes. The 845 doesn’t just plug in like other tubes, it has a bayonet mount, like some European light bulbs. The sockets need to be large, because the 845 triode, often used in radio transmitters, operates at much higher voltage than common audio tubes. It also requires a lot of drive signal. That explains the large number of smaller tubes, of course. Some designers actually drive the 845 with a 300B, which is itself a power triode frequently used in single-ended power amplifiers.
     Unlike some power tubes, the 845 is commonly available at reasonable cost.
     Look at the back of the Leyla, and you’ll see the usual input jacks, the IEC power cord connector, and an easily accessible line fuse. You’ll also notice that there are eight output posts rather than the usual six, mounted on the top panel. Unlike nearly all modern tube amplifiers, the Leyla has outputs for 16 ohm speakers as well as 8 and 4 ohms. Hardly anyone still makes 16 ohm speakers, but some audiophiles sacrifice some of the already scarce output power by using that setting. The reason: the 16 ohm transformer winding has only half the wire of the 8 ohm winding, and a quarter of that of the 4 ohm winding.
     There’s also a surprise: an extra pair of jacks enigmatically marked “connector,” and a switch labelled “direct.” You can use them to turn this integrated amplifier into a power amplifier.
     As on other Antique Sound Lab amplifiers, both input and output jacks are of good quality. However the binding posts are oversized, preventing us from using our trusty Postman wrench on it. We used a conventional wrench instead, being careful not to overtighten. It’s easy to shear off even a quality binding post!
     You’ll have noticed that this amplifier has a name rather than the number/letter combination that identifies most of its brandmates. Leyla is the young daughter of Tash Goka, president of Divergent Technologies, North American distributor for Antique Sound Lab. The factory is more than willing to modify designs to specifications, and to add whatever name is desired. This means the Leyla has no exact equivalent elsewhere in the world.
     Our amp was far from new, but its two output tubes were fresh from the box, and so we gave it some 50 hours of extra run-in time before we connected it to our Omega system. Our Reference 3a Suprema speakers have a 4 ohm impedance, and we used the appropriate output on the Leyla. These speakers are efficient enough, at 91 dB, to operate with low power, though the presence of their twin unpowered subwoofers are a challenge to some amplifiers.
     We began the session with Copland’s Fanfare for the Common Man (on Reference Recordings RR-93CD), whose wideband dynamics are a challenge for the entire system, not least the amplifier and speakers. Yes, we could hear that this amplifier has only a small fraction of the power of our Moon W-5, especially at the fairly high volume setting we had selected, but that limit was not what stood out. The sound was warm and spacious, with a resultant separation of the different brass instruments that weave in and out of this impressive piece. The orchestra seemed to be a little farther back than with our reference amplifier, but that was perhaps just as well. Albert would have liked a little more substance to the large bass drum, and Gerard noted the slight fuzziness of the brass in the loudest passage. Both of those artifacts, we suspect, would vanish with some of the even more efficient loudspeakers that are increasingly easy to find...

(This is an excerpt from the full article. Want to ot everything we said about the Leyla amplifier? Just order issue 63 at our secure server.)

Complete articles from this issue:
Soundproofing, Big Screen TV's to Stay Away From, Passion A11, State of the Art

Excerpted articles from this issue:
Comparing the Incomparable: Listening in the Store, Antique Sound Lab Leyla, Vecteur Espace, Two Interconnects, Five Speaker Cables, Four Power Cords