Channel Islands Audio D-100 monoblock power amplifier:
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"Some of the other class-D amplifiers use switching power supplies, but I just don't think they sound good enough yet to use in audiophile amplifiers—they're probably all right for subwoofers, but I still think a linear supply is the best thing for an audio amplifier.

"I don't pretend there's anything especially sophisticated about the D-100's power supply. It uses a custom 300VA toroid, and it uses discrete Schottke diodes in the bridge rectifier. We use eight parallel capacitors—we like paralleling caps rather than just using two with large values because that tends to lower the overall ESR (Equivalent Series Resistance) and gives you more legs to charge. It also makes them more reliable because you have a lot more circuit-board area supporting the weight of the capacitors. One of the problems common to a lot of amplifiers that use large caps is that the weight of the caps breaks them loose from the circuit board when they are shipped.

"A lot of the things I do when I design products concern factors other than sound quality. Sound is always my priority, but we do a lot of things that don't directly affect the sound in order to ensure greater reliability. This comes from my background in customer service: It's really important to offer a good response to problems, but it's better to look ahead so the customer doesn't have the problem in the first place. Using multiple capacitors does give you better sound quality and it improves reliability—it just takes longer for us to build."

So building a reliable product was one of your design goals?

"Well, sure. I like to tinker, but I also want my stuff to work when I want to listen to music. In addition to reliability, my other consideration was to create an amplifier that was easy to build. We wouldn't have to think about that if we were designing an expensive high-end amplifier, but we consciously designed a high-end amplifier that offered the maximum performance for the dollar. We couldn't charge $1599/pair for amplifiers that took a whole day to assemble. On the other hand, one of the benefits of using a simple circuit is that we can use high-quality parts. A switching power supply takes about 100 parts, while an equivalent linear supply takes about 15."

The difference between a rut and a grave is the depth
The D-100 is so small and manageable that I fantasized about placing the pair of them on small stands directly behind the speakers and connecting the speakers' binding posts to the amps' posts with Deltron plugs alone. No wire. 'Tain't that easy, as it turned out—different binding posts have different spacings, so I'll have to put a hold on that idea until I get the right speaker. Or more gumption. Besides, I reasoned, that's not how most people would be using them, nor was it a system that allowed me to make comparisons to other amps. Still, I'm tempted to give it a go. It would be different.

Their small size meant that I could put the D-100s very close to my speakers, however, so I used a long interconnect and my shortest speaker cables. I was able to put the D-100s under the speaker stands supporting the Dynaudio Special 25s and directly behind the Thiel CS1.6s and Peak Consult Empresses. I initially used Cardas Golden Reference speaker cable, but it was so stiff and the spades were so large that I had problems dressing the cables. Stereovox's banana-terminated Studio HDLS cables and Shunyata Research's Lyra proved more manageable (although at $1250/pair, the Lyras seem an unlikely mate for the D-100s; I primarily focused on the $599/pair HDLS). A quartet of Golden Sound DH Squares under each D-100 got them off the floor.

There is little difference in people, but that little difference makes a big difference
I got the blue LEDs glowing, began to listen, and . . .

And not much, actually. For a product that looks so different and employs such different technology, I didn't notice much of a difference. There was superb separation between the channels (as one would expect from monoblocks), deep taut bass, and lots of airy detail—and that was with the Thiel CS1.6s, which, while quite efficient, do "suck more than twice as much current as an 8 ohm speaker from the amplifier to achieve that high sensitivity," in JA's memorable assessment in his review of the speaker in the September 2002 Stereophile (Vol.25 No.9).

In other words, the D-100s stepped right up to the plate and performed as if they'd been in the big league forever.

At the Home Entertainment 2005 Show in May, I fell in love with Art Dudley's copy of the Del McCoury Band's Del and the Boys (CD, Ceil 2006), especially "1952 Vincent Black Lightning," so I wasted no time acquiring a copy of my own. The motorcycle ballad was one of the first things I listened to through the D-100s and they absolutely nailed it, from Del McCoury's high lonesome vocal to the zingy banjo overtones of Rob McCoury's Osborne Chief and the solid bottom of Mike Bub's acoustic bass.

Wait a minute! These little thangs are producing sound like this? Now that's different.

Over time, I substituted the Dynaudio Special 25s for the Thiels, and then I received the Peak Consult Empresses fresh from their appearance at HE2005. Each speaker has its own personality, of course, and through the D-100s each sounded quite different from the others—always a sign that the system upstream isn't imposing its sonic signature on the whole shebang. The Thiels were coherent and clear, if not particularly extended on the bottom end, while the Dynaudios were warm and extremely listenable, if a tad forward on top. And the Empresses? Big and open and—no, I'll be talking about those in October. Let's just say they sounded distinctly different from the others. Good, though.

One thing remained constant, however: The D-100s sounded big and spacious. If a recording had a big soundstage, they gave me big. A good example was Chesky's Rockin' the Spirit: Piano Blues, Boogie & Spirituals, recorded live with a single-point microphone midway between two grand pianos (SACD, Chesky SACD296). Some of the solo pianists chose the Steinway on the left, others chose the Baldwin on the right, and the duets were played on both, obviously.

We audiophiles get so used to hearing performers smack dab in the middle of our soundstage that a recording like Rockin' the Spirit is a welcome tonic. Sure, you get the piano at stage left or stage right, depending on which one is being played, but if your system is up to it—and the D-100s were—the acoustic remains big and enveloping no matter where the instrument is. And then there's the crowd response, which the D-100s placed in the room with such believability that I jumped every time someone shouted encouragement. Not just the first time, but in every late-night session.

I could babble on about microdynamics and suchlike, but let's skip to the chase: I was so there.

In theory there is no difference between theory and practice. In practice there is.
After testing a new sample of the Coda Technologies S5 stereo power amplifier (May 2005, Vol.28 No.5), JA left it at my house for additional listening. Even though, at $3750, the S5 is more than twice the price of a pair of D-100s, it seemed a likely subject for a level-matched comparison.

I began with the Hilliard Ensemble's CD of Guillaume de Machaut's Motets (ECM New Series 1823), and the Coda and the CIAs sounded pretty darn close. Both captured the big acoustic of Propstei St. Gerold, and both placed the tenor lead quite distinctly nearer the listener than the other vocalists—and the decay on the individual parts was rendered with delicacy and precision. With the motets, I was hard-pressed to choose between the amps, which was pretty good going for the D-100s.

Things were less equivalent with Pierino Gamba and London Symphony's Rossini Overtures (CD, JVC JVCXR 0229-2). The D-100s presented a large soundstage and lots of dynamic resolution, but the S5 captured the snare-drum rolls in La Gazza Ladra with a tighter brrrrrp. The snares sounded looser and flabbier. The Coda also kept the lid on the fortissimo passages better, handling them with more ease—the D-100s sounded as though they were teetering ever so slightly at the edge of control. Exciting, but not, I suspect, an accurate reflection of the LSO's performance.

On Rockin' the Spirit, the amps were again very close. Both the CIAs and the Coda gave me a big soundstage with lots of enveloping spatial cues, but I felt the S5 better conveyed the body of the pianos, especially in regard to the strong left-hand work of the four stride pianists. This wasn't entirely an issue of bass response, though I did feel the S5's bottom end was ever so slightly tauter. It was, rather, more that the bass lines were better integrated with the middle and upper keyboard lines. I have no idea why I was aware of this with well-recorded solo piano—and piano four-hands, of course—and not with the Rossini overtures, but there you go. Comparisons can be full of surprises.

The biggest surprise, of course, was how well the Channel Islands D-100s acquitted themselves going head to head with an amp as good as the Coda S5.

It's easy to make a buck. It's a lot tougher to make a difference.
Difference. That's what high-end audio is all about, after all. All things are seldom equal—we all have different preferences, priorities, and, yes, budgets.

Channel Islands Audio's nifty little D-100 amplifier is extremely well built—the fit and finish are superb. I kept having to remind myself that a pair of them costs less than $2000. A lot less.

And that was just looking at them—I really had to keep pinching myself as I auditioned them. In performance, the D-100s might be giants; the fact that they're so small is just icing on the cake. It means you can put them just about anywhere. I think I'll keep a pair around as a reminder of just how good affordable high-end can be.

You might want to do the same.