Charlie Hansen, Ayre Acoustics Page 2
Hansen: Sure, but it's a tough world out there, and there are a lot of good products to compete against.
Phillips: And, you finally have the K-1 preamplifier to flesh out the line.
Hansen: We're really happy with the K-1—it disappears more than just about any preamp I've ever heard. If you had to pick one thing that contributes to that more than any other, it would be that volume control. Everyone knows that a stepped attenuator is superior to a pot, but they've got two things against them: they're expensive and the steps are too coarse. We solved the second problem by doubling the number of steps to 46—unless you've got some really weird gain situation in your system, our stepped volume control is virtually indistinguishable from a pot. Cost is another thing entirely [laughs]. It's probably the most expensive volume control ever made—it has solid silver wipers and solid silver contacts. Everything else is second-rate in comparison.
I strongly believe in balanced circuits. The only way to accomplish volume control in balanced circuitry is to use a stepped attenuator—at least the way I figure it.
We are fanatical about the components we use. We match every transistor we use on a circuit board—each circuit board in a K-1 has 24 matched transistors on it. That's a lot of work, and the phono section is even worse. Of course, that's because we use no feedback in the circuit. If we used feedback, we wouldn't have to go to so much trouble. I'm convinced that feedback is a bad idea—at best. In the best case, it's not too bad; in the worst case, it's really awful.
Phillips: Take a minute and describe the K-1's circuit topology.
Hansen: All FET, completely balanced from input to output, and as simple as we could make it. It has an input stage, then a cascode, and then source-followers to give low output impedance so that you can drive things in the real world—that's it. Basically, the signal only goes through three transistors from input to output. Everything is direct-coupled; the line stage is a true DC amp.
A lot of people are real big on servos, but think about what you're doing with a servo circuit: You take a stupid little op-amp that happens to have good DC characteristics (low drift and low offset) and you stick it in the feedback loop, so that the loop now has gain, because the op-amp is amplifying the feedback, and then you try to filter out the signal so that you are only amplifying the DC. Do you see how silly that is? It works fine on the DC, you end up with zero DC offset, but because there's gain in there, you end up amplifying some AC as well. You can filter that out with capacitors, but that's 6dB/octave and you end up with a high-feedback amp in the middle of your feedback loop. You just can't make a notch filter precise enough to compensate for that—I can't, anyway.
I think the thing that shocked me most was the amount of resolution the K1 presented in such a natural way. High-feedback designs have a different kind -of resolution. Listen to all that detail! you tell yourself—you don't hear anything more than you heard otherwise, it just sticks out more. But it ain't right. And I finally realized that I'd never heard a phono section without feedback before.
Phillips: Most of the time when we speak of increased resolution, we think about the Dark Side of the Force—we get more and more of the detail, but less and less of the music.
Hansen: Certainly! And we keep going through cycles—the late '50s represented an upswing, the '60s a downturn, and then there was a backlash—people rebelled against the prevailing sound and went back to tubes, Levinson started perfecting solid-state, and we had better and better sound until the mid-'80s. Then the tide turned again. CDs came in and people started focusing on things like low noise and convenience, and we seemed to go off sonically again. I believe that the single-ended-triode phenomenon is mostly a backlash to this type of gear. I don't think anybody ever said, "What I need is a 7W amplifier," or "I wish my amp was more colored."
But I do think that people are tired of paying $5000 or $10,000 for an amplifier that doesn't do justice to the music. I think that's what's driving the SE triode thing—they sound good and some of them are relatively cheap. They make music fun.
That's what we're trying to do at Ayre. We want the gear to make beautiful music that is compelling and captivating, and we want the stuff to boogie and be maintenance-free—and we want to do all that at a fair price.