Review: Furutech ADL Esprit Headphone amp and DAC/ADC
Furutech are a Japanese company very well known for their cable products, the other most well known being Oyaide. It was interesting to see that fairly recently, they had started branching out into making audio equipment under the name of ADL, which stands for Alpha Design Labs. Their portable amp, the Cruise and their first USB amp product, the GT-40 (which includes a phono stage) were quite well received, though are fairly unknown on Head-Fi. While at the Fujiya Avic Headphone festival in Tokyo, I saw that they had a new product, the Esprit, which combines a DAC, pre-amp and headphone amp and managed to borrow one briefly to give it a quick go. Since I liked what I heard, I arranged with Furutech for a loaner for review.
The unit itself is in a very solid aluminium box consisting of 4 main parts held together with 8 allen (hex) screws. The controls and rear jacks are all high-quality parts befitting a unit costing only a few tens-of-dollars shy of $1k. Not only that, but it has no less than 5 inputs -- 2 analogue and 3 digital and all in a relatively tiny box. Alongside that, the USB input includes an optical digital output to allow a signal to be passed to another device.
However, this isn't merely a headphone amp and DAC but is also an ADC, that is, it can be used to record from analogue sources such as musical instruments, record players (though you need a phono stage) or the like onto your computer. It also acts as a pre-amp if you have active speakers. This makes it a very versatile box and possibly a good solution if you want something better than the (usually awful) line in on your computer for recording something to your computer.
Completing the picture, the front panel has lovely, large selector and volume knobs, as well as an attenuator switch for the recording function next to an LED indicating when the input signal is clipping.
Internally we find the now fairly ubiquitous Tenor TE7022 USB receiver, in this case used for sending digital audio both directions. It allows 44.1 kHz (CD quality), 48 kHz and 96 kHz digital audio in both directions. Notably absent is 88.2 kHz which is only an issue if you are someone who frequently purchases music from HDTracks as some of their recordings are sold at that rate. DAC and ADC are respectively the Wolfson WM8716 and Cirrus CS5361 units, both capable of handling data up to 24/192. Amplification is handled by a trio of Texas Instrument BB OPA2134 opamps, which are socketed, allowing the end user to replace them with other opamps if desired. A little disappointingly given the high quality case components was the rather basic volume attenuator (in yellow top left in the picture). For $900 I'd like to see at least a good ALPS unit.
I tried the headphone amp with a variety of headphone types to see how well it performs. With my Symphones Magnums, with which I first tried the Esprit in Tokyo, the sound was precise, if a touch mellow, likely a result of the OPA2134s.
Doing my usual tests to find the limitations of the design, I first turned the volume to maximum without any music playing and there was a tiny amount of hiss, not a significant enough amount to worry me, especially given that with the Magnums "loud" started at 10am on the volume dial. There also seemed to be a bit of DC in the output, as turning the volume dial produced a "scratchy" sound through my headphones.
A more difficult and unexpected test was the Sony XBA-3s. With 3 balanced armatures they have a impedance curve from hell that plays havok with many amplifiers. With these the Esprit didn't sound too happy, with the treble rather bright and the rest of the sound seeming to lack in dynamics, but they are 16 Ohm IEMs, which is the lower limit for the Esprit. Third up were a pair of MB Quart (now German Maestro) QP 400s which I keep around for high-impedance testing. With these the Esprit seemed happier though, being bright headphones a little harshness in the treble was apparent.
The Esprit was most happy with my LCD-3s, which, despite the lacklustre power specifications seemed to be driven quite well, with no issues even if I turned the volume to maximum (not with the headphones on my head, however). Likewise, the Esprit also did a fine job as a pre-amp for my ADAM ARTist 3 speakers. If anything, it was the latter two combinations which I found the Esprit sounded at its best.
Usefully, the Esprit can easily be tweaked a little by way of changing the inbuilt opamps. Inside there are three, one for each of the pre-amp, headphone amp and a third the purpose of which I didn't check. Switching, for example, the OPA2134 for the headphone output with the NE5532 results in the sound becoming less mellow but at the expense of there being a little more hiss in the output. A pair of AD797BRZs on a Browndog adaptor resulted in a sound that was marginally less flat than the stock opamps.
The DAC itself is USB powered. Very handily, it can pass through a digital signal the optical digital output even when the main unit is off. With the USB plugged in, the power button, blue when the unit is switched on, glows red with the unit switched off to indicate that the USB input is still functional. Someone wishing to pass through digital from their computer's USB using optical to another device would find this very handy.
With all these inputs and outputs available, I initially scratched my head whom this unit would be suitable for. Recently having started to use my XBox again it became very apparent: Gamers! I've seen quite a few pictures of members' set-ups where they have both a computer and console, hooked into headphones and speakers. With such a set-up, the Esprit could be the perfect unit for both listening to music from a computer then switching to the input from one's console (usually optical), sending the output to either a pair of active speakers or headphones. The quality DAC inside the Esprit would be good both for music and games where an accurate stereo image is beneficial. Gaming headphones too tend to be low impedance models such as Audio Technicas AD900s (now AD900X) which I feel are most likely to be a good match for the Esprit.
An often-asked question is whether or not someone should buy an internal sound card for their PC or an external unit. With all the complexity of DACs, then amps, a small, one-box plug-and-play solution is welcome. Considered thus, the Esprit shines when considered this way, as it is effectively an all-in-one amateur recording studio-type device with a good headphone amp. In that regard all it is missing is balanced input and output. As a headphone DAC/amp alone, at $900+ it is in the price territory of a lot of seriously good equipment. The Woo Audio WA7 I recently reviewed, for example, can handle everything from sensitive IEMs to planar (orthodynamic) headphones with ease, where the Esprit isn't quite as versatile. However, the headphone output on the Esprit is distinctly better than the one in my Metric Halo ULN-2 (a very highly regarded pro DAC/ADC). At its Japanese price which is (today at least) closer to $760 the price is very reasonable considering the feature set.
In the end, if you want a small, neat and very functional unit with a good headphone amp to integrate into a computer/music system, this is worth considering. Now if only ADL could drop the US price closer to the Japanese one...