I've been listening to the Audeze Deckard for months on my desktop, and I've taken it for granted. It was just there, doing its job so well that I didn't really think about how it sounded, but when I started paying attention to write this review I really came to appreciate what the Deckard does. In case you were wondering, the Deckard is a combination headphone amp, stereo preamp and USB digital converter. Audeze sells the Deckard direct for $699 with free shipping in the US, and it's £599 in the UK.
This crisply designed amp sports two inputs -- USB and stereo analog RCA -- and there are stereo RCA analog preamplifier outputs on the rear panel. Up front it has a 6.3mm headphone jack, and input and gain (low, medium and high) selector switches. I stuck with medium gain for my headphone and desktop speaker listening sessions. Plugging in a pair of headphones automatically mutes the speakers' sound. The Class A headphone amplifier supplies a very healthy 4 watts per channel; and the built-in USB digital converter accommodates up to 192-kHz/24-bit files. The all-metal chassis, with its distinctive side-flanking heat sinks measures a trim 6.1 by 11.5 by 1.8 inches (155 by 292 by 42 millimeters).
I paired the Deckard with my reference self-powered desktop speakers, the Adam Audio F5s (US $460, UK £298 per pair), and now that I'm really focusing on the sound I know why the Deckard was so easy to take for granted. It's effortlessly clear and clean, like it's doing nothing at all. The soundstage is spacious, and never "stuck" to the speakers; bass is full, defined and deep, and best of all the treble is refined and pure. So the Deckard/F5 system is unusually easy to listen to for hours at a time. Ryuichi Sakamoto's brooding score for the "Revenant" soundtrack floated in free space in front of the F5s.
For headphones, the Audeze EL-8 (US $699, UK £599) seemed like the obvious match, so I mostly listened to that pair with the Deckard. The pristine clarity of the sound combined with sure-footed bass definition never failed to bring out the best in great-sounding recordings. Even so, iffy MP3s and YouTube videos were listenable.
I also tried the Deckard with my high-impedance (600-ohm) Beyerdynamic DT 880 headphones, which sounded more transparent than usual. The DT 880's really clicked with the Deckard. I next tried a set of low-impedance (32-ohm) Cardas Audio A8 in-ear headphones, which up to that point I'd only used with my iPod Classic and Astell & Kern Jr music players. With the Deckard music sounded a lot better, significantly more open (less stuck inside my head); midrange was more expressive and natural overall. The Deckard brought out the best in every pair of headphones I used with it.
I also tried substituting a Nordost Blue Heaven headphone cable (US $400) for the stock Audeze cable, and heard significant transparency gains with the Blue Heaven cable. The EL-8 headphones sounded mighty clear and open with the stock cable, but the Blue Heaven cable was a nice upgrade, eking out more of what I like about the EL-8's sound. Nordost offers a complete range of Blue Heaven cables for full-size headphones.
I covered a lot of ground here, but the Audeze Deckard amp, Audeze EL-8 headphones and Adam Audio F5 speakers are an altogether terrific desktop system, and a worthwhile alternative to a more traditional stereo system.