Pros: Smooth but pretty neutral, great detail/soundstage, Amazing build, neat
Cons: Nothing for this price!!
I just wrote this for my blog so I thought I would post it here too.
A&R Cambridge Ltd. (or Arcam to the rest of us) are well established in the field of hifi audio, 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 is transferred to an asynchronous USB for the Texas Instruments PCM5102 DAC chip to convert - up to 24bit / 96khz - audio into glorious analogue. There are also RCA sockets for connecting the DAC to an external amplifier or powered speakers. A logo of this calibre on such a multi-talented device for only £150... This seems too good to be true.
The rPAC has a very clean and open sound. The experience is very neutral but if I had to pick I would say it's very slightly on the warm side. This slight push in the bass is nothing offensive and suits Classical or Electronic music equally well. My most notable impression from the rPAC is a great sense of smoothness. There is plenty of detail on tap to impress here as well, it never fails to impress when rendering fine details. The soundstage is great too, giving a great 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 mosr headphone it will not be a problem but anything above 300ohms may struggle for some people and/or some music (depending on the individual a bit of course). With the 600ohm Beyerdynamic DT880 the rPAC managed loud levels only if there was little or no exterior noise. A less than quiet environment and 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 for example.
It's a testament to how clear the sound is that even the best compressed music is starting to feel dull on the rPAC. I keep moving over to my lossless collection and everything feels more alive. I know this is a hot topic, I am sceptical about these things, but this is how it's making me feel about music. Anything less than 320kbps feels really grating to my senses.
This paragraph probably shouldn't be in the I had some sporadic issues with the rPAC cutting out. A quick hissing noise and then it seems to crash completely and needs reconnecting. This seemed to happen more on certain computers. On one computer certain USB ports that it was connected to caused Windows 7 to BSOD (Blue Screen Of Death), and that is very bad!
The rPAC itself crashing seemed to happen mostly while Spotify was playing and perhaps this is related to it the rPAC demanding 24bit audio. I noticed this when running Foobar and JRiver (MC17), both programs force the music to be up-sampled to 24bit or they refuse to output anything to the rPAC. I am assuming that the reason you don't normally have issues is Windows fixing the problem without asking you. I noticed the Audiolab M-DAC also insisted on an up-sampling from the software if you try to force it to NOS (Non Over-Sampling) mode.
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 just after two minutes in this is broken up by a moment of drama, both ends of the scale sound utterly immersive. The rPAC is able to dish out smooth musicality and delicate detail with equal amounts of impressiveness?
- 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" - Yes I know this is not the original, but it's really good! I stumbled across this one going through my Dad's collection. If you have a Spotify account then you'll have access to several great versions of this track, including the original "Voodoo Chile" 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. The opening is a great example of the
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 the 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 in decent quality.
The Yulong U100 is similarly priced to the rPAC and also good as a desktop DAC because it has RCA line outputs which are useful if you split your headphone usage up with the odd bit of computer speakers. The Arcam's audio signature is a little bit warmer than the U100 but not by much, I've heard warmer that I still think are great so I think this will provide a happy mid-ground that is likely to suit most people. The Yulong is priced a little higher than the rPAC, it's also much larger and needs to be plugged in to 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's audio signature is warmer 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 better 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 it gets 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 here. 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, mid-range, 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 call it looked 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 shows that the rPAC's 96khz maximum sample rate is due to a limitation the USB interface (or rather it's drivers) because the rLink supports 192khz with the same DAC chip.
The only buttons you get here 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 buttons have plenty of granularity to the volume level, great for IEMs 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. The unit is set to maximum volume when you get it too so be warned.
The rPAC comes with a healthy set of parts. Apart from getting 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 an big so you can also get some cables in there too. Of course you get a USB cable, it's a simple one but most people won't care about that. 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 frame of 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 - that'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 a very thick frame (which is most of what you see on the outside), the circuit board and chips weigh next to nothing. It feels rather overkill for strength so perhaps this added weight is assure a good footing when it's sat on a desktop. Moving 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 stick-on rubber feet, which are common on most other DACs.
Try as I might I just couldn't find any real weaknesses to the rPAC armour. It's neat, has great features and superb build quality, but most importantly the audio isn't just good, it's stunning!
When I first saw the rPAC I was initial concerned that the AV giant was cutting off more than it could chew with their first combined DAC and headphone amplifier. I assumed that for this price corners would have to be cut everywhere and that audio quality would suffer. It's up against some tough competition from Asia too. Companies like Yulong and Audinst have had more experience with these niche products and have done an absolutely stunning job so far. After listening to the rPAC however my scepticism quickly melted away. As a desktop DAC I would put this near the top of a very long list but as a portable USB DAC it's a truly stunning machine that will be hard to beat.
With it's balance of warmth, clarity, detail and three-dimensionality the Arcam rPAC is now my favourite DAC and headphone amplifier for laptop listening. It's not the smallest or lightest of them, but the build quality is as good as it's sound and the addition of RCA line-outs really adds to it's versatility.
If you're looking for the ultimate in transparency (which suits my warmer headphones a little better), or have very hard to drive headphones then I would perhaps push you towards the Yulong U100 but if you want a sound presentation that is more on the sublimely smooth side whilst not sacrificing much detail or soundstage then the Arcam is very easy recommendation. The fact that the manages this while running from USB power is nothing short of spectacular.
OK here are some rather pointless photos of the internal circuit board, but perhaps they will entertain some. I guess I've got the bug for taking things apart now :P. It's a very simple device to disassemble but unlike the Audinst HUD-Mini there is nothing fun to play with, like op-amps.
I'm kind of curious to know what the 20 pin header, labelled 'CON1', is for. It looks like the ones you get on computer sound-cards. Anyone know what this is for?
Here is the PCB sitting in the lower half of the chassis, next to the under side of the top half. Underneath is the felt draw-string bag that comes with the rPAC. As you can see by the under side of the chassis - the dark colour is sprayed on. I imagine any scrapes/scuffs to the top plate and corners will show through to the lighter metal, but so far I haven't seen this.