April Music Eximus DP1 DAC/Headphone Amp/Preamp (Hi-Fi+)

Equipment report
Solid-state preamplifiers,
Digital-to-analog converters,
Headphone amps and amp/DACs
April Music Eximus DP1
April Music Eximus DP1 DAC/Headphone Amp/Preamp (Hi-Fi+)

First there was Aura, then came Stello. And now, the South Korean based April Music has a high-end brand on its books by the name of Eximus. Once, Eximus made CD players, but with the current changes in the spinning disc’s fortune, it’s little wonder the brand turned to a multifunction DAC, the DP1. Eximus currently also produces a matching ICEpower 125W power amplifier, alongside the products from Stello and Aura. Although Stello’s handy U3 digital standards converter will be the subject of a later review, it’s the DP1 were interested in here.

This is a lovely little design, beautifully finished with a leaf motif set into the top of the Alex Rasmussen designed alloy case. If high-end audio is about look and feel, this has loads of both and has a look reminiscent of a less utilitarian Nagra. Whether or not it has any bearing on sound quality, there’s a lot to be said for a product you feel the urge to stroke. It bespeaks quality.

Under that alloy case, the DP1 is all business. The six digital input converter uses a pair of PCM1794A DAC chips in dual mono mode and separate oscillators for multiples of 44.1kHz and 48kHz. As well as asynchronous USB Class 2.0 input, AES/EBU, Toslink and a pair of Coax S/PDIF digital links, it even features an I2S input, if you are lucky enough to have a digital source that supports this (such as PS Audio’s PerfectWave player). USB Class 2.0 allows higher than 24/96 precision files to be transferred across a USB cable, and requires a driver install for Windows computers (Class 2.0 USB comes as standard with a modern Mac).

By default, the DP1 upsamples to 192kHz, 24bit precision. The way you tell is the LED next to the ‘Upsample’ button on the front panel: green for 24/192, red for 24/96 and no LED glowing for pass-thru. Similarly, the lock LED (next to the source button) glows yellow if it’s a 44.1/48k signal, red if it’s an 88.2/96kHz sample or green if it’s a 176.4/192kHz signal. This does mean that you might end up with an input signal at 192kHz upsampled... to 192kHz, although I tried upsampling to 192kHz at the source (via Pure Music) and ‘reupsampling ‘ to 192kHz and it didn’t seem to upset the sound. April Music suggests setting it to Bypass as a starting point, but every time you power down the DAC, it will default to 192kHz upsampling. Not a big pain, but something you might need to remember time after time.

There are three ways of thinking about the DP1. It’s a DAC, a DAC with a preamp, and a DAC with a headphone amp built in. The three ways of the DP1 potentially ally it to three very different end users. From a writer’s perspective though, this is relatively easy to process. With just the one analogue input (well, two... one a front-mounted mini-jack, the other single-ended line-level), no balance control and no remote handset option, the DP1 is not a big winner in the full-function preamp stakes. However, it sounds excellent when hooked to an amp as a pre (especially through the balanced outputs, I found), and if you can live with the limitations described above, you get the sound of a stripped down £2,000 line preamp, as well as a damn good DAC. But I suspect most of its time, it will either have the volume maxed out and used as a standalone DAC, or used as the mother of all headphone solutions, and in both cases it works brilliantly.

There’s a consistency, a commonality of sound both through the main and headphone outputs. Whichever way you shake it, there’s a lot of taut, tight and controlled bass, a midrange that is just a step forward of neutral, sweet upper mids and a treble that is extended and natural. All of this can be summed up in one word: ‘big’. Playing the Belcea Quartet playing Debussy’s String Quartet in G highlighted the scale of the system. Usually, when played through headphones this can sound a trifle small, as if the cello is small and distant (part of this is down to lateralisation effects – it sometimes sounds as if the cello is playing just behind your left eye). Here, it sounds like real-sized instruments playing, and playing well.

Moving over to ‘Superstition’; by Stevie Wonder, the acid test of any good DAC is the way it handles that hi-hat in the introduction. It’s a deceptively complex rhythm, and usually something that is either swamped by the mix or reduced to a simple 4/4 root time signature. In fact, every bar that normally metronomic hi-hat is slightly different to the one before, and this crucial, but subtle detail is usually lost (like the squeaky drum pedal).

I briefly borrowed a pair of HiFiMAN HE-6 headphones, not just because they are some of the most revealing cans on the planet, but also because they are notoriously difficult to drive. And the Eximus DP1 treated them as if they were Just Another Headphone: OK, so the volume dial needed more of a yank than usual, but rather than just hide clipping and terrified from the nasty load, the DP1 sailed through the test without a single scar. Granted, the Trilogy 933 headphone amp showed up the limitations of the DP1 both in terms of dynamic range, more definition, ultimately higher volume levels without distortion and low-level volume control, but despite of all this, the DP1 didn’t let itself down, and if it can drive the HE-6, it can drive practically anything this side of a pair of Stax electrostatics. Bear in mind that the Trilogy 933 is about the best headphone amp I have ever heard, and you’ll get an idea of how good the DP1 is by comparison.

There’s a hugely interesting observation with the DP1. I’ve not encountered a system so ruthlessly revealing of data reduction before. I have a very pragmatic approach to the likes of AAC and MP3 – put simply, as storage is cheap, go with the best possible format you can, but if you can only buy the album as an AAC or MP3 download, don’t sweat it. Had I been using a DP1 all this time, I wouldn’t be so pragmatic. The difference between lossy and lossless (or uncompressed) files was exceptionally clearly defined through the DP1, especially through its headphone output. The wishy-splashy sound of piano notes blurring together, the hashy fuzzy sound that overplays a drummer riding a hi-hat, a sense of added ‘sizzle’ to a solo female vocal... all those elements that highlight less-than-transparent data reduction algorithms are more noticeable than ever on even high-rate MP3. Once you get past 192kbps VBR (variable bit rate) AAC, the data reduced signal is commonly considered to sound functionally identical to the original, but if those who commonly considered such things routinely used something like the Eximus DP1 and even a pair of Sennheiser HD-25 IIs, they’d be lobbying for less intrusive data reduction.

I suspect this is down to exceptional digital processing performance on the part of the DP1. Why? Because it doesn’t make a hash of less-than-perfect recordings. It shows you what is going on in the studio or stage. So, when you are listening to something like ‘The Bard Lachrymose’ from Bradford Marsalis & Joey Calderazzo’s Songs of Mirth and Melancholy played losslessly, you get the sublime recording and the excellent performance shining through. Play Lifts to Experience and the music’s great but the lo-fi sound is harsh, but still insightful. Do the same on AAC versions of the same and the first is peaky, the second almost unlistenable.

If you do have a lot of AAC recordings, April Music does have an ace up its sleeve in the guise of the U3 standards converter. This will be the subject of a review next issue, but the little box, fed properly through its USB port and outputting to AES/EBU softened the AAC blow considerably and made the music sound good again. The combination of Mac, U3 and DP1 was more than the sum of its musical parts, and while we’ve considered the DP1 as a standalone device, the U3 shouldn’t be overlooked as the ultimate performance enhancer for the DAC.

Cut to the chase: the Eximus DP1 is no ‘me too’ product. It’s one of the best of the best money – any money – can buy. It’s an outstanding headphone amp, a fantastic DAC and a none-too-shabby basic preamp in one. If this is the future of audio, tomorrow’s looking damn fine!


Digital Input: 1 USB 2.0, 1 I2S 100 Ohms TTL Level, 2 COAX 75 Ohms, 1 AES/EBU, 110 Ohms, 1 OPT

USB 2.0 PC OS: Windows OS with Driver, MAC OSX
Input Sampling Frequency: USB 2.0, I2S, DIR(AES/EBU, COAX, OPT) Max 192kHz UpSample: TI SRC4192
DAC: TI PCM1794A x 2 (Dual Mono) 192kHz/24Bit
Dynamic Range: 132dB TYPICAL THD+N: 0.0004%

Frequency Response: 2Hz to 95kHz -3dB Analog Input: 1 RCA, 1 minijack Analog Output: 1 RCA, 1 XLR, 1 1/4” Headphone Jack
Dimensions (WxDxH): 20.8x29.1x6.2cm
Weight: 3.6 kg

Price: £1,995

Manufactured by: April Music
URL: www.aprilmusic.com

Distributed by: Igloo Audio
URL: www.iglooaudio.co.uk
Tel: +44(0)1892 532995