Solid State Power Amp Reviews

The auteur theory of the cinema, first described in the 1950s by François Truffaut, states that a great movie represents the artistic vision of one person, usually the director. Moviemaking may involve collaboration, but it cannot be done successfully by a committee. There has to be a single individual in charge, one whose sensitivity and world view is reflected in the movie. In the same sense that the author of a novel is telling a story through the medium of print, the director of a movie is telling a story through the medium of film.

What, you may ask, does this have to do with the reproduction of sound? Isn't it just a matter of accuracy, which is not an act of creation but of re-creation? Then a better analogy would be with a documentary film, which tells it exactly like it is. Ah, but that assumes that it's possible to tell it exactly like it is, without bias or a point of view--and anyone who's seen documentaries knows that, even when supposedly unbiased, they always have a point of view (and if they didn't, they'd be pretty boring). The maker of a documentary decides what to include and what to exclude, what to emphasize and what to de-emphasize, just as the designer of audio equipment—hold on, I'm getting there—makes design choices that allow sound to be reproduced in a way that represents his or her version of the truth.

The components from YBA provide exemplars of auteur theory in audio. They're all designed by the man whose initials they bear: Yves-Bernard André. They're built in a small factory in Bures-Sur-Yvette, a village just outside Paris, the building itself designed by Yves-Bernard André. YBA components use custom-made resistors, capacitors, and wiring; in the top-of-the-line YBA Signature amplifier, even the transistors are rebuilt by Yves-Bernard André himself. Every piece of equipment that leaves the factory is listened to by Yves-Bernard André.

During a brief after-hours visit to the YBA factory, I noticed that partially-built components on a long workbench had white cloth covering them, to ensure that they're not contaminated by even the slightest amount of dust. The metal plates covering the transformers on YBA 1 amplifiers that had just undergone final testing were hand-marked with an arrow, indicating the plate's proper orientation. When asked about this, Yves-Bernard told me that the metal crystal orientation has a significant effect on the sound, and, even though the covers are all supposed to have been installed in the same way, he personally checks this by listening to the amplifier while changing the orientation of the metal plate. Can you imagine this sort of attention to detail from a mass-market manufacturer?

Perhaps the most striking thing about YBA amplifiers is their size. In a world where it's assumed that bigger is better, YBA has deliberately kept their products compact. "Size Isn't Everything" was how they put it in their advertising a few years ago: an ill-chosen slogan for a male-dominated industry, but one that may have been occasioned by examining competitors' products containing mostly air within a coffin-size box.

The YBA 1—the YBA 1 Alpha HC, to use its precise model designation—is compact but heavy, so it compares well with amplifiers in its price range if we use specific gravity as the criterion. It uses two C-core transformers (with the top plates oriented correctly, of course), and the chassis is heavily damped and built in such a way as to "channel" vibration away from sensitive components. The output devices are mounted on mica and copper in order to reduce capacitive effects. Cooling surfaces are overdimensioned and printed circuit boards are double the usual thickness.

Yves-Bernard André places great emphasis on the importance of reducing the number of components in the signal path, and of minimizing their characteristic "sonic signatures." He refuses to enter the power race, pointing out that a doubling of output power represents only a 3dB increase in volume, which he feels is not very significant in the context of typical listening levels that can vary from 80 to 100dB. What he acknowledges to be very important is current capability, ie, the ability to deliver voltage into the complex low-impedance loads that many speakers present. In fact, the YBA 1 has only slightly greater 8-ohm power than the much less expensive YBA 2 HC, reviewed by JA in January 1994 (85W vs 70W), but the YBA 1 is said to deliver 1.8kW into a 0.7 ohm load (the YBA 2 has no 0.7 ohm power output rating).

The YBA 1 is described as dual-mono, with two separate power supplies and 60,000µF total power supply capacitance. Only minimal negative feedback is used. A protection circuit is activated in the event of the output being shorted or because of an internal problem. Because this circuit is in the feedback loop, it is said to be without audible effects. The design is what YBA calls "class Alpha," which means that the driver stage is class-A but the output stage is class-A/B, an arrangement that is said to maintain the sonic advantages of class-A design while allowing for cool running and low power consumption. Unusually, there are no series passive components (resistors or capacitors) in the signal path, only transistors.

The YBA 1 is an exceptionally attractive piece of equipment—"elegant" is the best descriptor I can think of. Fit'n'finish are impeccable, in the Rowland/Krell/Mark Levinson class. However, the physical design is not without its quirks. The first challenge is finding the power switch: On some YBA products, it's the YBA sign itself on the front panel, but pressing that sign on the YBA 1 does absolutely nothing. There's no switch in the back, either. The power switch is actually hidden behind one of the handles on the front panel—not a problem once you know where it is, and the location does prevent accidental tripping by pets and small humans.

The YBA 1 sports two sets of speaker terminals, allowing convenient bi-wiring, but they're banana jacks rather than the five-way binding posts more common in North America. YBA provides adapters to be used if you have cables with spade lugs; although the adapters are well-made, this arrangement is not entirely satisfactory, in that it introduces another set of potentially signal-degrading contacts.