After the Graham Slee Bitzie USB DAC, it’s the turn of the Arcam rPAC USB DAC to take place beside our Sennheiser PX-100 headphones. The Arcam rDAC is a DAC targeting a wide audience, fitted with a compatible 24 bit and 96 kHz USB port (and 24 bit / 192 kHz after firmware update), an RCA cable output and a 3.5 mm mini-jack headphones output. This device is designed to be connected to a computer to play the digital music stored on it.
Arcam has used the Texas Instruments Burr Brown PCM 5102 chip, capable of working on 24 bits and 192 kHz, which is limited here by the device’s USB controller.
New: Arcam has decided to increase the rPAC’s audio stream capacity, which after downloading an ASIO driver and new firmware, is now capable of decoding audio stream up to 24 bits and 192 kHz.
Packaging contents
The Arcam rPAC USB DAC comes with a USB A-B cable and a pair of RCA cables. This DAC is powered by the USB port of the computer to which it’s connected.
The product’s manufacturing quality is highly impressive. The Arcam rPAC is particularly heavy (300 g), but this hasn’t anything to do with the components which make up the device, but is due to the weighting of the case which avoids any major damage to the device. Arcam has fitted the rPAC with a rubber base to ensure stability on any smooth surface. One of the features is an LED, situated at the top of the device. It changes colour depending on the state of the DAC ? red when it’s connected but receives no audio stream and green when a stream is being decoded. The two volume knobs lower or increase volume gradually.
Test conditions
We listened to the Arcam rPAC USB DAC on Windows with Sennheiser PX-100 and HiFiMAN HE-500 headphones. Our USB test cable, the Audioquest USB Coffee (which we will soon review) was costly but excellent. Although the Arcam rPAC USB DAC is plug and play and works with any audio streaming application, we decided to go with Foobar2000.
Remember: audio streaming to a USB DAC must be carried out by avoiding, as much as possible, the Windows mixer. This mixer implies sampling rate changes which alter the sound, without taking into account the fact that the regularity of data pack transmission is variable.
Foobar2000 manages several audio streaming protocols which avoid any problems by communicating directly with the USB DAC ? Kernel Streaming, ASIO and Wasapi. Strangely, the Arcam rPAC USB DAC refused to operate in Wasapi mode with Foobar2000, but this mode didn’t pose any problem for the XBMC software. We mainly tested the Arcam rPAC with Foobar in ASIO mode, after installing the ASIO4ALL software and the ASIO Output module for Foobar2000.
Please note: the Arcam rPAC was not detected by our NAS Synology DS212, nor micro-PC operating in OpenElec (XBMC).
Note: these problems are resolved once the Arcam rPAC’s firmware is updated. This firmware can be downloaded from their site.
Our listening impressions
The Arcam rPAC DAC delivers an unflattering, almost concerning sound balance during its initial hours of operation. Bass is rich and treble is slightly in the background. This USB DAC doesn’t sound good immediately, unlike the Graham Slee Bitzie (which gradually improves thereafter). Patience is required with the Arcam rPAC, but it’s well worth it.
Listening, which can sound a little too quiet at first, gradually improves in terms of dynamics over the course of time, demonstrating a genuine aptitude at undoing the most complex music. Take for example Racine Carré by Stromae (FLAC 16/44) and its synthetic ?pumping? sonority and you’ll notice that the Arcam rPAC never lets itself overrun. A quick visit to Youtube to listen to Stromae’s Deezer session and the range of his voice is delivered with success.
The same for When Tomorrow Comes (remastered/2005, 16/44) by Eurythmics, whose complex arrangement (or even, some might say, ramshackle) finds a consistent density with the rPAC. Likewise, Led Zeppelin’s live O2 Arena album (2007, FLAC 24/48), although extremely vast, lets you hear and appreciate the sound of the audience.
On the soundtrack of The Dark Knight (2008, FLAC 16/44), we note important dynamic jumps and good channel separation. Sound delivery is balanced with good presence in the low-medium and medium. Bass goes down very low and literally shakes your ears on the title ?Why So Serious?.
We could perhaps criticise the Arcam RPAC for not being a little bit more adventurous with certain sound takes or for its cautious mixes, but give it an explosive track and it will immediately be a hit which you’ll get caught up in completely. For example, with Daft Punk’s Lose Yourself to Dance (24/88), there is a depth and breadth we don’t often hear.
Voice delivery is very good for both female and male voices. Love is a rebel bird interpreted by Maria Callas (FLAC 16/44) is remarkably well delivered with the male choir easily finding its place.
This general neutral sound lends itself well to old sound takes, which are low in high frequencies. Stormy Weather by Oscar Peterson (16/44) is a good track to listen to without the fear of being ?attacked’ by an aggressive sound. The medium range is explored in detail but without any trouble for the listener. Peterson’s piano is well placed alongside the trumpet.
Conclusion
Whether it’s with headband headphones like the Sennheiser PX-100 or the audiophile HiFiMAN HE-500, it’s difficult to find fault with this little USB DAC which excels with its overall control. ?Low price? doesn’t necessarily mean average quality.
This DAC offers a generally neutral sound, without being strong in treble, but detailed in low medium and often fearsomely efficient in bass.
Note: we decoded FLAC 24/176 and 24/192 files using Foobar2000 in Asio4ALL mode as well as in Wasapi mode via XMBC using Windows. The same operation is usually impossible with a non-certified 24/192 DAC. This leads us to believe that Arcam could have certainly developed a driver to operate this rPAC in the original resolution of its Texas Instruments Burr Brown PCM5102 chip.
One final word ? a few weeks after our initial test, the breaking-in period of this DAC took longer than we had anticipated. After a few hundred hours, the treble range proved itself to be more present and lucid, which provided a more appealing balance. The Arcam rPAC is clearly more analytical than the Graham Slee Bitzie USB we previously reviewed.
