Can a portable headphone amplifier satisfy demanding audiophiles?

There's good sound, and there's high-end sound; the difference is in the details. Case in point: the little Cruise USB digital-to-analog headphone amplifier from Alpha Design Labs by Furutech.

The Cruise sounds clear, clean and remarkably transparent. Regarding the details, connectivity comes in two flavors, there's a 3.5 mm analog stereo line input and 24/96 USB digital input. The Cruise can run off its external AC power supply, internal rechargeable lithium ion battery, or USB power from your computer. Furutech claims the battery is good for 80 hours of playback time.

High-end gear has to look the part, and again the Cruise scores. It may be a little thing, but it feels solid. Mirror-polished, nonmagnetic stainless-steel end caps flank a curvy, high-gloss carbon fiber body. Resting on my desktop the Cruise absolutely looks the part; it's the real deal.

I started my listening sessions with my 12-year-old Sennheiser HD 580 full-size headphones. I have to admit that I never really used them all that much over the years. They are "hard to drive" and can sound lifeless and boring with a lot of amps, and only sound their best with above average headphone amplifiers. With the Cruise, the HD 580 had extraordinary resolution, but not so much it ever went too far and sounded bright. "Grain" in the audiophile lexicon refers to a subtle gritty haze superimposed over the sound, and it can be so subtle you only really start to notice it when you hear an amplifier that doesn't have grain. That would be the Cruise. It's oh-so smooth and sweet, it handily brings out the best in most recordings.

Next I hooked up my JH-13 in-ear headphones, and was amazed by how much more open (less inside my head) they sounded with the Cruise. A bootlegged Max Roach drum solo CD packed a mighty wallop, and bass seemed more powerful than I get with the JH-13 plugged directly into my iPod. What a difference!

I also tried my Bower & Wilkins P5 on-ear headphones. The P5 was more muscular than ever, less laid-back and mellow, but more transparent. It sounds like a better headphone than I thought it was.

Those remarks refer to the sound I heard at home with the Cruise hooked up to my Mac Mini computer via USB, and when I was on the go I plugged my iPod into the Cruise's "line-in" jack (with an Apple 30-pin to 3.5 mm adapter cable). You can also use the Cruise with any portable device with the included 3.5 mm to 3.5 mm cable. The Cruise sounded nearly as sweet from my iPod as it did with my computer, and it was a pleasure having this level of sound quality in a portable package.

The Cruise sells for $475. If you can do without the carbon fiber body, the Furutech Stride is much the same and goes for $350. Nice!