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.
FEATURES/TECHNICAL HIGHLIGHTS (both Cruise and Stride)
•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.
o1 USB (Mini B type) input for connection to a PC.
oMini-jack (3.5mm) analog line level input.
oMini-jack (3.5mm) headphone output.
oThumb wheel volume control.
SET UP AND USE
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.
Input connections are either analog using a 3.5mm mini jack cable, or digital using the supplied USB cable. For portable use, the amp comes with a stretchy pouch that includes a pocket to hold your iPod or other personal music player. This makes for a tidy if somewhat hefty bundle that you can stick in your pocket, although you’ll need to pull your player out if you want to change tracks or make other adjustments. Fortunately, the headphone jack and volume control are both at the same end of the amp, so it’s easy to make volume adjustments without having to pull the amp out.
Making the USB connection to my Windows laptop was no problem; it simply connected automatically and switched over from the laptop speakers when I plugged the cable in. I was able to play files using several audio players including iTunes, but for most listening I used Winamp, adjusting the maximum output resolution to match the amp’s 96kHz/24-bit capability.
In use I found the amp had a few quirks including an audible pop when I turned on the power, and a noticeable level of background hiss. This was especially audible when I was using my Ultimate Ears UE-10 Pro in-ear monitors, sounding quite similar to analog tape hiss. The volume control also produced a low level rustle as you adjusted the level at times, although this would remedy itself if you worked the volume dial back and forth a couple of times.
Despite its compact size, the ADL proved to be quite capable of driving most of the headphones I had on hand. Tougher loads like the HiFiMan HE5s were no sweat, and I found I could crank it up pretty loud and still have plenty of punch and control. More likely partners for on-the-go use that I tried included the previously mentioned Ultimate Ears, B&W P5s, Monster Turbine Pros, Thinksound ts02s, and Etymotic hf5s.
The first test of any portable headphone amp is whether it can outperform whatever personal music player you’re using with it; otherwise, what’s the point? Happily this isn’t a problem for the ADL, which easily outstripped both my iPod Classic and my iPhone 4 in its ability to drive headphones with plenty of dynamic nuance and drive, while opening up a clear window onto the recording.
Tonally the ADL is quite neutral, yet it has an uncanny ability to exploit the strengths of most headphones without highlighting their weaknesses. For example, it did a great job of pumping a little extra life into the super smooth yet somewhat laid back B&W P5s, pulling more detail and transparency from the upper midrange than I’m used to hearing from that model. On the other hand, the Etymotic hf5s balance typically puts a spotlight on the midrange, yet the ADL managed to really flesh them out in the lower octaves, getting a detailed grip on the bass energy in the recording.
One upshot of the ADL’s upper midrange clarity is the impressive spaciousness and finely focused detail of the soundstage. On good acoustic recordings it was easy to identify the space occupied by each instrument, separating out the layers of a recording with plenty of breathing room for each performer. Soundstage width was good, but it was the sense of depth on suitable recordings that really had me impressed.
With so much dynamic life coupled with its exceptional transparency, the ADL really manages to hold its own even against some dedicated home amps. Still, a comparison with the $800 Musical Fidelity M1HPA showed how the bigger amp’s pure class A circuitry gives it a slight edge in subtler micro-dynamic shadings. The M-F amp also presents the music against a blacker, quieter background, making it a bit easier to pick out the tiniest nuances.
While most of my listening was performed using the ADL’s analog input, the built in DAC is certainly no afterthought. Comparing WAV rips from the same CDs using the iPod into the analog input against the laptop through the USB, showed a small but clear preference for the digital connection. Tonal contrasts were more vivid over the USB, giving the music a richer overall sound.
You may have noticed that I have generally referred to the Cruise and Stride collectively as the ADL amp. To see if I could detect any differences between the two amps, I did perform some careful comparison tests. First, I adjusted the volume controls on each amp to the exact same level using a test tone while measuring the voltage at the headphone socket. Then I played several tracks, alternating back and forth between the Cruise and the Stride. While at times I thought I had a slight preference for one over the other, these impressions were not reliable, and on the following trial any slight preference would often swing the other way. This isn’t a subtle way of saying that my hearing is going off, just that any possible differences were so tiny that they became irrelevant. I think that the question of whether the Cruise is worth the additional cost really depends on how much you value its slick cosmetics.
Art Pepper’s Intensity [OJC] is one of this legendary alto sax player’s finest albums and it comes with the bonus of the amazing sound Contemporary Records would regularly deliver back in the early 1960s. On the track “Too Close For Comfort” the way Pepper’s sax soars from a subtle whisper to an in-your-face blast was quite startling through the ADL using the Ultimate Ears. Yet at the same time the air and space around Frank Butler’s drums, and the tunefulness of Jimmy Bond’s upright bass was never overwhelmed by the sax. The B&W P5s in particular loved this track through the ADL, bringing out the smoothness in Pepper’s tone, without dulling the bite of the top notes in his range.
Led Zeppelin’s Houses Of The Holy [Atlantic] is probably their most densely woven recording, reflecting the experimentation they brought to the recording process by using a lot of natural acoustic spaces. On The Ocean there’s a lot to sort out, but the ADL amp did a good job of helping me to unravel the layers. The acoustic space around John Bonham’s drum kit was clear and distinct from those surrounding the guitar and vocal tracks, and the famous ringing telephone during the guitar solo was easy to pick out. That’s pretty impressive for a little portable headphone amp.
With the Cruise and Stride, Alpha Design Labs/Furutech has managed yet again to deliver a product that punches well above its weight class. With its excellent built in USB DAC, it can also do double duty as a home/desktop DAC/headphone amplifier, although its connectivity really makes it more of a road machine. It biggest strength is how it somehow manages to get the best from whatever headphones you use, exploiting their strengths while minimizing any weaknesses. A superb all rounder.
Consider this Amp/DAC if:
•You want a portable amp that also works well at home.
•You want to get the best from your computer-based files while on the road.
•You want a portable rig that can go for the long haul on a single charge.
Look further if:
•You are sensitive to a subtle low level hiss and use in-ear monitors.
•You require a DAC capable of 192/24.
•You want something super slim that can disappear into your pocket.
Ratings (relative to comparably-priced DACs/headphone amps):
•Design & Features: 7
•Tonal Balance: 9
•Timbral Purity: 8
•Detail & Resolution: 9
•Value: 6 (Cruise) 8 (Stride)
Once again, Furutech’s Alpha Design Labs shows us that they really know how to make a versatile product that covers a lot of potential uses. The Cruise and Stride are two essentially identical amp/DACs, only one’s dressed in casual clothes while the other is wearing a tuxedo. Personally, I would get the Stride and use the price difference to buy more music, but I understand how looking cool is critical to some. Either way, you get a fantastic tool for extracting the most from your tunes while on the road, that continues to perform when you’re kicking back at home.
SPECS & PRICING
Alpha Design Labs by Furutech Cruise and Stride portable DAC/headphone amps
Inputs: USB (mini B type); analog 3.5mm mini-jack
Outputs: One headphone output via 3.5mm mini-jack
D/A converter: Wolfson WM8716
USB controller: Tenor TE7022L
Output power: 78mW (12 ohm), 94mW (16 ohm), 110mW (32 ohm), 98.6mW (56 ohm), 23mW (300 ohm), and 16mW (600 ohm).
Power source: USB 5V, included AC power supply, internal battery
Signal to Noise Ratio: 100db (A-Weighted - line in) 96db (A-Weighted - USB)
THD: 0.02% (Line Input 1KHz)
Channel separation: 60db (I kHz)
Frequency response: 20Hz - 20KHz +/- 0.5db
Input bit depth: up to 24 bits
Input data rate: up to 96KS/s (USB)
Dimensions (H x W x D): 1.1” x 4.73” x 2.56”
Weight: 7.0 oz./198g (Cruise); 6.7oz./190g (Stride)
Included accessories: USB cable, 3ft; A/C Power Supply; Setup Guide; Microfiber carrying pouch
Warranty: One Year
Price: $540 (Cruise); $395 (Stride)
Alpha Design Labs by Furutech