My interest for April Eximus DP1 started because of a combination of reasons. First of all, the introduction of their U3 unit, in an era where the main trend has been to deal with computer audio, and usb-related issues (mainly, jitter rejection, and bitperfect reproduction).
Personally, I have been passionate about digital cables since getting in touch with a capable Canadian maker, Moray James, whose digital coax cables let me hear how marked the differences could be before the signal goes into a dac. Comparisons with other cables, like Belkin Synapse Platinum, often mentioned in sites like GoodSoundClub, made me even a stronger worshipper of digital transports.
The U3 is regarded as a very good usb to spdif converters available.
My interest towards the Eximus DP-1 had born after I sold my favourite Dac, a Museatex Bitstream, for a need of upgrading. I ended up regretting the sale, given its vivid colours and midrange quality, regardless of the low end dac chip it was using (Philips SAA bitstream line).
My buyer (a Russian fellow, nick-named mock-up on this website) proved having taste similar to mine, with a general appreciation towards its analogue sounding presentation, and was a collector of upgraded Museatex DAC's. Ha favoured my Bitstream over his other units, mostly given its magical midrange, and despite some bass overabundance. He was using Stello U3 and Art Legato as usb transports.
At some point, he gave me heads-up towards the Eximus DP- 1 as his new favourite, introducing its sonic qualities to me as a more neutral take on the Bitstream presentation.
Afterwards, I also read 6moons review, which I found equally interesting, but I admit I wouldn't have trusted it alone without having received my friend's impressions beforehand.
The Eximus DP-1: DAC section
The DP-1 is a very neat solution, because, in a single box, it includes a usb receiver akin to the U3, but without the further need of a spdif cable, ruling out any further signal degradantion, and, most importantly, digital cables paranoia. It then incorporates amplification section.
The DAC section uses a dual TI PCM1794A chip.
The DAC is capable of producing a very intimate, lively sound, with strong musical presence. Top to bottom, it's a midrange-forward take over neutrality. This makes for a focused soundstage, cohesive tonal balance, and very involving music reproduction (some would say 'toe-tapping').
The bass and high frequencies are very clean. The bass, to me, sounds fast and tight. Treble, as a general characteristic, is very refined, delicate, nuanced. Microdetails retrieval is very precise, but there is a general sense of smoothness, so everything is placed in the space without sounding edgy, nor sticking out of place (like, instead, happens a bit with Audio-gd NFB-9.2).
The soundstage of the Eximus DP-1 is precise and focused, it makes the listener feel as the target of the music. This gives a strong sense of involvement and intimacy. By comparison, the Audio-gd offers a larger, more expansive soundstage, but with a more-recessed than neutral midrange and some sense of coldness.
Compared to my older Bitstream, which I have come to know thoroughly, the Eximus offers similarly forward midrange, although a bit less meaty, and cleaner, faster bass. The bass in the Bitstream was a bit too fat, but it also threw the deepest bass I have heard, given the overall quantity.
I am under the impression that the slightly 'forward' midrange area of the DP-1 is the mid to upper midrange... I will write more about it during the headphone amp paragraph.
Unlike some other people said, I don't consider the DP-1 very forgiving: although it can magnify beautiful recordings and vocals, it is very sensitive to lossy files. I can immediately tell the difference between V0 mp3's or 320kbs mp3's, against my FLAC collection. In this regard, the Bitstream was much more forgiving / opaque. To me such discerning capabilities of the Eximus DP-1 are very welcome, especially given the overall involving, focused and delicate character that it offers.
A few other notes about the upsampling (it works, somehow adding a tiny bit of energy to the high frequencies), the headphone filter, which I consider a bloated and detached bass boost; and the USB transport, which doesn't present any problems related to artifacts, in my unit (while I did have problems with Audio-gd NFB9.2 out of the box).
Headphone amplification, and headphone synergy
I have read some differing opinions in another thread, but I can only speak for my tests and discoveries.
I have used the headphone amp during the comparison of the Dac unit with the Audio-gd NFB-9.2.
I have also directly compared the headphone amp against the Burson HA-160DS I was lent.
I have used the Eximus DP-1 with Sennheiser HD-800, Hd-650, Grado SR-325i (all three in a local shop in center of Milano), and my own Etymotic ER4S and Audio Technica AD2000.
In general, I feel that the Eximus amplifier is noticeably better than Burson headphone amplifier. The Burson offers a general sense of power, with a bit of fat, cloudy bottom end, and a slightly unrefined high frequencies. I had put the Burson amplifier, sonically, on par with the diy CKKIII amplifier made by Cavalli, although different, as the latter, to me, sounds better with low impedance headphones, is more linear, and slightly more edgy and less powerful.
The Burson is also pretty sensitive to noise coming from the wall. The Eximus amplifier is more linear than the Burson, noticeably more transparent, has smoother treble.
Testing it with HD800, the overall sound of the combo was 'almost' involving: I consider Sennheiser HD800 to be a very cold can, and easily sibilant. In this case, the DP-1 drove the HD800 wery well, the sound was very spacious, with black background, authoritative, super fast bass (although I don't like the bass of the HD800, its sense of hypertexture is unrealistic to me), and the midrange to treble balance was more normal than the other time I had heard it (with Rotel gear).
With the HD650, I noticed two things: the sense of snappiness of the bass, along with a general sense of control; the HD650 still sounded like and HD650... not that i doubted it, but I have yet to hear a balanced HD650, which is usually said to become 'something else'.
I didn't have any luck in finding an HD600, which I believe should be one of the best matches possible with the Eximus amplifeir and general tonality.
By comparison, the CKKIII, which I tried with HD650 and HD580, in the first case sounded too thick, dark and sibilant at the same time; the HD580 simply sounded too slow and boomy.
The ER4S (or, in this case HF5 + PtoS adapter), that I often use as a 'lense' for the overall balance of a headphone system (mostly because I have been using Etys for years on basically anything I have owned, or tried at other people's place), sounded strong in the bass, with zero noise, warmish tonality and zero sibilance, as I expected by fitting them with biflanges, and deep insertion. By comparison, Audio-gd NFB-9.2 has some edginess with the same Etys.
Audio Technica AD2000 are the only headphone that I didn't find ideal when paired with the Eximus. The AD2000 have a peculiar frequency response. Their best description was written by Asr. Anyway, they have quick, tight bass, which I don't find lacking in impact, and very detailed, but super smooth treble. The midrange is their critical part, because its the headphone's most founding characteristic. The mids and especially the upper mids are very upfront. I liked the description Asr made, by saying 'while other headphone are walking, they are always running, and they are running at you'.
In the case of the Eximus, I detected some lack of sinergy due to this, because the AD2k, which can already sound a bit too hot at times, with the DP-1 have too much push in the same area. I found them to gain a bit better balance with Audio-gd NFB-9.2, because of its opposite approach (slightly recessed mids from an ideal neutral, flat 'line').
The Eximus DP-1 provides great value for the money, especially if one wants to use dynamic headphones, and is a fan of Sennheisers (I would say any), or headphones like Audeze LCD2.
Its internal preamplifier and stepped attenuator add up to the value, and make for a great basis for a speaker system (which unfortunately I can't test at the moment).
Super midrange forward headphones, like Audio Technica AD2000 or Tamboti Thunderpants might have some problems with its midrangey, lively take... Etymotic ER4, while being midrange forward as well, aren't that excessivea and sound good and involving.
Since I am not fan of most of the high end dynamic headphones, I would rather use electrostats (with the associated cost of an electrostatic amplifier and analogue cables), so my personal use of the integrated headphone amp would be reduced to something like HD600, or Grado HP-2 (in which I am very interested).
People loving HD800, Audeze LCD2/3, Qualias, should consider the DP-1 as a very good valued system, and a 3000 usd system is more easily justified under these headphones.
If wanting to use electrostatic headphones, there is the associated cost to consider, but the integrated amplification circuitry isn't lost given the presence of the preamplifier, so that only power amp would be left to buy for a speaker system.
Edited by antonyfirst - 7/1/12 at 7:37am