Sutherland Engineering 12dAX7 USB DAC/preamplifier:
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Okay Computer Sound
I've been using a pretty-good-sounding and very inexpensive (ca $200) Onkyo SE-U55 outboard USB-based converter with my Mac G4. It has optical and coaxial digital as well as analog line inputs and outputs, and built-in A/D and D/A converters so that, with the appropriate recording software (I use Peak LE 2.58 for Mac), I can feed it a cassette deck's analog output and store it digitally on the G4's hard drive. The Onkyo also has a headphone jack with volume control, which the Sutherland 12dAX7 doesn't, so for sheer versatility, the SE-U55 can't be beat. But while the Onkyo sounds pretty good, and much better than the G4's internal converter, it didn't come close to matching the 12dAX7's sound: rich, warm, sweet, airy, a bit fat on bottom, and, overall, BIG.

In a computer-based sound system of small satellites and a sub listened to in the nearfield, "accuracy" in the usual audiophile sense isn't the issue. It's more about compensating for the limitations of the associated equipment and, especially when listening to MP3s, the software. Although I have a DSL line, I have no interest in downloading MP3s—but for this review I went to www.geffen.com to listen to a track from Peter Gabriel's new album, Up. Gabriel's albums have always been well-recorded, even the digital ones, so I'm sure what I heard at 95.8kbps via RealPlayer was a shadow of what Classic Records' two-LP vinyl edition will sound like. The MP3 didn't sound bad, mind you, especially the bass, which was robust and well-controlled, but from the midrange and up it sounded gauzy, kind of flat, and cartoony. But compared to Evatone "sheets"—which is how I got to hear promo music as a kid—this was da bomb!

The 12dAX7 greatly improved the sound of all three satellite subwoofer systems I used it with, providing a cushion of air where otherwise there would have been a parched sonic landscape. It smoothed over jagged edges and softened the impact of barbed-wire transients. Most impressive were the improvements in imaging, soundstaging, and harmonic development. Images became more solid and three-dimensional; the soundstage widened and deepened, with far more coherent center-fill; and the stingy harmonic envelope positively bloomed. The added midbass warmth meant that I needed to adjust the various subwoofers' levels and/or placements, but once I'd achieved that balance, the sound had a rich, addictive, honeyed glow that was particularly effective for classical music and acoustic rock.

Beck's new Sea Change is a string-drenched, minor-key acoustic set magnificently recorded at Ocean Way Studios. The CD sounded dramatically full-bodied and detailed without giving up transient clarity or the resolution of inner details. As good as the Aego2 system sounded connected directly to the Mac's analog audio output, it sounded cleaner, clearer, and more detailed using the USB-based Onkyo SE-U55. The 12dAX7 took the Aego2's performance to a higher level, and did likewise for the two other computer speaker systems I tried.

Another Configuration
I tried the 12dAX7 in my main stereo system, driving it with my Mac iBook. I got the same rich, full-bodied sound as with my G4 system, but something about the overall presentation bothered me. I didn't take the time to analyze precisely what was going on, because I suspect that most purchasers will be using the 12dAX7 on their computer desktops, and not as a component of their main systems. But if you are thinking of using the Sutherland with a laptop in your big rig, don't let my experience deter you—especially as Sutherland Engineering offers a money-back guaranty.

Conclusion
Sutherland Engineering has come up with a unique, fine-sounding, computer-friendly DAC/vacuum-tube preamplifier. It should enrich and improve the sound of any computer-based sound system. However, the $1600 asking price seems steep. I'm not sure what justifies this price, given that the 12dAX7 is sold factory-direct and is basically a full-function USB receiver, digital filter, and DAC, all on an over-the-counter chip to which has been added a case, a decent power supply, and a pair of one-tube gain stages with volume control.

With a 12dAX7 in the system, there's no reason not to invest in a good powered satellite-subwoofer system, or even a pair of high-quality conventional speakers driven by an external amplifier. The Acoustic Energy Aego2 now sells for $399; add a 12dAX7, and the total of $2000 spent offers a level of sonic performance I hadn't thought any desktop rig could provide. If you spend a lot of time at your computer, can crank it up, and have $1600 to drop, the innovative 12dAX7 is definitely worth considering.