A&R Cambridge or Arcam as it's known these days is well established in the field of hi-fi proper, but it could be said that the rPAC represents a departure from their usual products. It's true that they've made DACs before, but not combined with headphone amplifiers, not USB powered portables and not this reasonably priced. Data at up to 24bit, 96khz is taken by an asynchronous USB input where a Texas Instruments PCM5102 DAC chip converts it into glorious analogue. As well as the headphone output there are RCA sockets for connecting the DAC to an external amplifier or powered speakers. A brand of this calibre on such a multi-talented device for only £150. It seems too good to be true.
Used with V-moda Crossfade M-80 headphones the rPAC has a very clean and open sound, the experience is very neutral but if I had to be picky I would say it's very slightly on the warm side. A slight push in the bass is nothing offensive and suits classical and electronic music equally well. My most notable impression from the rPAC is a great sense of smoothness. There is plenty of detail on tap as well, it never fails to impress when rendering fine details. The soundstage is great too, giving a real sense of dynamics to the depth and dimension. This is easily the best USB powered sound that I have heard.
Although being USB powered doesn't seem to impact the sound quality it does limit the volume level somewhat. For most headphones it will not be a problem but anything above 300 Ohms may struggle for some people and/or some music (depending on how loud you want to play). With the 600 Ohm Beyerdynamic DT880 the rPAC managed high volume levels only if there was little or no exterior noise. In a less than quiet environment there could be issues. As USB powered audio volume goes, the rPAC is among the better ones that I've tried, the Audinst HUD-Mini is much more problematic with harder-to-drive headphones.
It's a testament to how clear the sound is, that even the least compressed music is starts sound dull on the rPAC. I kept moving over to my lossless collection because everything feels more alive. I know this is a hot topic, I am sceptical about these things, but this is how the rPAC made me feel about the music. Anything less than 320kbps feels really grating to my senses.
As mentioned I used V-moda headphones for the listening at the time of the review but have subsequently been using the rPAC with Beyerdynamic DT770 Pro Limited Editions and SoundMagic HP100s and getting great results with both.
Previously I've avoided talking about specific music tracks in the DAC and amplifier reviews. I was worried that it would get confusing, but I'm going back on this as I feel it will help better describe certain sound characteristics.
Rodrigo Y Gabriela: Buster Voodoo. Listening to all Rodrigo Y Gabriela's music is sublime on the rPAC. This track shows how well it handles fast paced music, but also how powerful and sharply detailed the guitars sound while not feeling harsh. There is a real sense of smoothness here that is intoxicating.
opendoorsclose: Night (Soundcloud). This electronic track was made by a good friend of mine. Like most electronic music this is a great test of the frequency extremes. Bass kicks hard, but is also well formed and nicely textured, treble is nicely articulate and not overwhelming. I also like this track for dynamics and soundstage, all of which come out really well here. The rPAC is really great for electronic music, but to be fair it's great for everything. It just makes the bold sounds stand out even more and I can't argue with that.
Chopin: Nocturnes No. 6 In G Minor, Op.15 No.3. The rPAC displays great poise forming the notes of the piano throughout this piece. Mostly this track is quiet and calm, but two minutes in this is broken by a moment of drama, both ends of the scale sound utterly immersive. The rPAC is equally good at dishing out smooth musicality and delicate detail.
Chris Tilton: Fringe (Season 3) Escape From Liberty Island. Ever since Chris Tilton's stunning 'Black' game soundtrack I have been following his career. From their early collaborations you can feel Michael Giacchino's influence in Chris' work and that's no bad thing. 'Fringe - Season 3' conveys a really great mood to the TV show and this is my favourite album/season of the three for it's sound. It comes through here with great presence, yet intricate delicacy. There is no hint of muddling when the track gets complicated and it has a lovely sense of depth too.
Stevie Ray Vaughan & Double Trouble: Voodoo Child (Slight Return). Yes I know this is not the original, but it's really good! If you have a Spotify account then you'll have access to several great versions of this track, including the Hendrix’s Voodoo Chile (Slight Return) from the 'Live In Stockholm - 1969' album. This version by Stevie Ray is my favourite mastering of the guitar work and let's face it - this track is all about epic guitar.
I own most of these songs on CD, they are ripped as lossless files and played on a PC. The audio is output through a generic USB cable, using WASAPI, event style on JRiver's MC17, buffering from RAM. I also chose these songs because they're on Spotify, so if you have a premium subscription you should be able to find them easily and check them out for yourself.
The Yulong U100 is the same price as an rPAC but has to be bought from China or Hong Kong as there is no UK distributor. It’s also good as a desktop DAC because it has RCA line outputs which are useful if you split your headphone usage up with speakers. The Arcam's sound is a little bit warmer than the U100 but not by much, I've heard warmer sounds that I still think are great so I think this provides a happy mid-ground that is likely to suit most people. The Yulong is much larger than the rPAC and needs to be plugged into the wall for power but what it lacks in portability and convenience it makes up for with superior texture and soundstage.
The Epiphany Acoustics EHP-O2D (£187) has a warmer sound than the rPAC's, which is no bad thing. It is worth noting because between the rPAC, the Yulong U100 and the Epiphany it's this aspect that'll make people prefer one over the other. It feels a little unfair to be comparing the Arcam to two units that are not USB powered however. The fact that it's close to these two is a real achievement but it is behind them in excitement levels. If you want portability then ignore the Yulong and Epiphany because they are not good enough to make up for this lack of convenience.
Perhaps something like the Audioquest Dragonfly can get closer to the mains powered DAC/amps but I haven't tried that one yet.
The Audinst HUD-MX1 is a great performing DAC, but for me its heavily overshadowed by the sheer performance of the Arcam. The two units share RCA line outputs and a similar footprint. The MX1 is a little less warm, which could be considered a good thing, but I preferred the rPAC's presentation. At £115 the MX1 is a bit cheaper than the Arcam, but the rPAC feels way more special than it's price. The detail, bass, midrange, treble and especially the soundstage feel much nicer on the Arcam but as well as all that, there is real sense of smoothness to the sound.
The rPAC is an interesting design. It's neat, well engineered and slick. Breaking away from the common shape of most similar devices it stands out as one of the more well thought out designs. I would say it looks unique if I hadn't seen the Calyx Kong, which apart from a slightly different button layout and no line-outputs is very similar.
If you look at Arcam's line-up now you will see another similar looking unit to the rPAC, called an rLink. Try not to mix these two up because the rLink doesn't feature a USB input and thus requires additional power. The rLink is also a DAC only, in other words it does not feature a headphone amplifier. Other than that the two devices are similar.
The rLink spec suggests that the rPAC's 96khz maximum sample rate is due to a limitation in the USB interface (or rather it's drivers) because the rLink supports 192khz with the same DAC chip. The only buttons on rPAC are for volume, they are however very well engineered, shiny and have a reassuring feedback when pressed. Although I prefer analogue dials, I can see that not having one makes the device more sleek and durable – thus better for portability. You get one button for up & another for down, but if you press both buttons together you will discover a mute feature. This is a nice touch, although I tend not to use it myself. The controls allow small volume steps which is great for IEMs (in-ear monitors) and high sensitivity headphones alike. I kind of miss having a display here as there is no feedback as to where the volume is set. Switch from low sensitivity headphones to high and you will probably get a bit of a shock. My unit was set to maximum volume when I got it too, so be warned.
The rPAC comes with a healthy set of parts. Apart from a 'thank you' card from Arcam there is a nice shiny manual (although there's not a lot for it to tell). You get a felt bag for carrying the rPAC around, this is nice and big so you can get some cables in there too. There is also get a basic USB cable. Last, but not least, you also get a set of interconnects so that you can hook the DAC directly to another amp, again they are a basic pair but this is a nice touch as they really didn't have to include these.
The rPAC is just a bit bigger than a deck of cards (100 x 62 x 25mm). The 300g weight feels a lot for something this small - it's nearly three times that of the all metal Fiio E17. This makes it feel substantial and sturdy, but this bulk is almost entirely due to the thick metal casework, the circuit board and chips weigh next to nothing. It seems like overkill for strength purposes so perhaps this added weight is to assure a good footing when it's sat on a desktop. Which moves me on nicely to my favourite part of the design, the solid rubber base. Looking almost the same as the metal top this keeps the design neat and slick. It's so much nicer than the stick-on rubber feet that you find on most other DACs.
This review was originally published on the noblehifi.blogspot.co.uk
DAC - TI PCM5102
Input - USB (Asynchronus)
Line output level - 2.15Vrms
Supported sample rates - 44.1kHz, 48kHz, 88.2kHz, 96kHz
Bit depth - 16-bit, 24-bit
Headphone output power - 138mW
Power requirements - 2.5W max
Dimensions (wxdxh, mm) 100 x 62 x 25
T 01223 203200