Furutech’s Alpha Design Labs division has a masterful touch when it comes to creating small yet affordable components that solve a myriad of audio needs. That was amply demonstrated a couple of months back when I checked out the firm’s GT40 USB capable phono stage and headphone amp. Now they have taken that same type of thinking on the road, with a pair of portable headphone amps featuring built-in high-performance USB digital to analog converters (DACs).
The ADL Cruise and Stride do a nice job of straddling the line between truly portable amps, and transportable units better suited to tabletop use. The 80-hour rechargeable battery and analog mini-jack input make them great partners for an iPod when you’re on the go, while the high-rez USB digital input lets you extract the best performance from your computer based files when you finally stop moving.
Cruise vs. Stride
Before going too far, let me clarify the differences between the $540 Cruise and the $395 Stride. Electrically, the two are almost identical, with just a couple of minor differences in the circuit layout near the headphone jack. Whether these small differences reflect a running change between the production dates of the two review samples, or a specific design upgrade between the two amps isn’t clear, although I suspect the former.
The key difference however is in the cases that hold the guts. The Cruise sports a slick carbon fiber finish that gives it a decidedly high-tech appearance, while the somewhat less lust-inducing Stride has a subtler yet still attractive black or silver painted aluminum enclosure. Other than that, the only visible difference is with the plates the form the ends of each amp, with the Cruise having shiny mirror-like chrome finish endplates as compared against the Stride’s simpler painted ends.
You might expect that the carbon fiber would make the Cruise weigh less than the Stride, but if you pick them up you’ll discover that the Cruise feels a bit more substantial in your hand next to its lower priced brother. I disassembled both amps, and found that the stainless steel end plates of the Cruise weigh almost three times as much as the Stride’s aluminum ends, and this accounts for most of the weight difference. More interestingly, it turns out that the Cruise’s main body is actually an aluminum extrusion similar to the Stride’s, only with an added carbon fiber wrap to give that techy appearance. The wrap is very well applied making it quite tricky to locate the seam, but under magnification I discovered that it’s right along the bottom corner near the thicker side.
Both amps sound great, but I’ll get into whether the $145 difference is purely a cosmetic one a little later.
• Wolfson WM8716 24-bit/192kHz digital-to-analog converter.
• Tenor TE7022L USB controller.
• Supported sample rates: Up to 96kHz at 24-bit depth.
• High-performance headphone amplifier 78mW (12 ohm), 94mW (16 ohm), 110mW (32 ohm), 98.6mW (56 ohm), 23mW (300 ohm), 16mW (600 ohm).
• A built-in driver for the USB connection.
• Powered by the USB connection, included wall-wart adapter, or built-in rechargeable battery.
• Compact design for portability.
o 1 USB (Mini B type) input for connection to a PC.
o Mini-jack (3.5mm) analog line level input.
o Mini-jack (3.5mm) headphone output.
o On/off switch.
o Thumb wheel volume control.
The ADL amp is refreshingly simple in layout, and that simplicity extends to getting everything hooked up and running. Power for the amp can come either from its built in battery, a powered USB connection, or the supplied wall-wart power supply. This means that on a trip you won’t need a source of USB power on hand to keep the amp fully charged.
Once your power source is connected, a red LED indicates that the battery is charging. I found that fully charging a depleted battery takes less than five hours, at which point the red LED turns green. The whopping 80-hour battery life means that even on a week long trip you’re unlikely to need a recharge, and I can’t think of a single portable music player that wouldn’t grind to a halt long before this amp.
As a device designed primarily for portable use, the ADL amp comes with a 3.5mm mini headphone jack rather than the bigger ¼-inch type found on most home headphones. That’s a pity, because I found the amp was more than capable of driving many big full-sized cans. You can always use an adapter as I did, but it would have been extra nice if they could have found a way to fit in both types. The thicker side of the amp’s unusual wedge shape is used to accommodate the big battery, but it looks to me like there would probably be enough room to cram a full-sized headphone jack in there too.