Ayre Acoustics K-1 preamplifier Page 3
"The power supply is choke-input-filtered," Hansen explained, "which is the only way to do it other than battery power. There's a large toroid, which is the power supply proper, which utilizes two smaller toroids as the choke. A fourth toroid serves as an RF filter on the incoming power line. [There are two additional ferrite rings incorporated into the power supply's umbilical as well.] We're trying to make the power as close to pure DC as we can.
"What makes the new, gallium-arsenide-based, Schottke rectifiers so different is that they don't use p and n junctions like a normal semiconductor diode; they just have one semiconductor touched by a metal. When you have electrons flowing through a normal semiconductor diode, in the n material they're the majority material, which is groovy, but when they flow through the p material they're the minority carrier. The minority carrier needs to get formed, and since there's no such thing as a positron in this universe—not for very long, at any rate—the p material carries the current in the absence of electrons.
This is a problem: When you reverse the current flow, it doesn't just stop right away, the minority carrier needs to 'unform'—that takes from 50 nanoseconds to a millisecond. During that time, you get reverse current flow—a really big spike, up to tens of amperes—of very short duration, which means very-high-frequency harmonics out to the megaHertz range. Ideally, you'd like that reverse switching time to be of as short duration as possible. By using Schottke rectifiers, which have no minority carriers, you eliminate that problem altogether. They go to a whole new level when it comes to removing switching noise."
Simplification is the realization of what is essential
Do I go on? Boy Howdy, does Hansen? Well, perhaps I do, but only partially because of Hansen's enthusiasm. He just loves to talk about the K-1—and I found it all endlessly fascinating. The K-1 is no me-too product. It's obvious that everything about it is the product of the most profound consideration—and of a unique sensibility.
But I wouldn't care about Hansen's ratiocinations one jot if the preamp didn't perform. My oh my, does it ever perform. So far, the fastest, most transparent preamp I've heard is Krell's $6900 KRC-HR line stage. Yet for all of its low-level resolution and absolute transparency, I could never get the sense of depth and space within the soundstage that Conrad-Johnson's $3995 Premier Fourteen so effortlessly conveyed. The K-1, like a Reese's cup, seems to combine the predominant characteristics of both of my favorite state-of-the-art preamps.
First and foremost, it is prodigiously fast and neutral. If the best preamp is no preamp, then the K-1—like the KRC-HR—is the next best thing to that. Using the Krell KPS-20i/l CD player's variable output—and matching the signal to within 0.1dB—I compared the sound with and without the K-1. If there was a difference, there was a smidge (but just a smidge) more sweetness through the K-1—but there was a profound increase in dynamics and soundstaging.
I hesitate to call the increased sweetness a coloration, since it was almost more sensed than observed. It reminded me of sharpening a knife—if you sharpen a knife on a good Arkansas or Japanese water-stone, you can get a cutting-edge that feels aggressive. But what you're feeling is really a flap of waste metal still attached to the true edge—you need to take it off with a butcher's steel (or, for finer edges, a leather strop). Otherwise, the first time you use the blade, that false edge will turn, blunting the true edge. Now maybe I'm just fooling myself with a slick analogy, but I felt that the K-1's sound had more of the true edge, no matter what disc I used for comparison.
I say I "more sensed than observed" that slight sweetening of the music because the K-1 is so damn good at passing information through—subtle information such as those signifiers that tell us something is live. I don't just mean the stuff that fools you into thinking musicians are present in the room playing—although I certainly had more than the usual number of "jump" incidences while auditioning the Ayre. I'm referring to other cues that make music believable and palpable.