Pro-Ject CD Box S2 Review

One of the latest products to join the Box Design range, the CD Box S2 (hereafter the S2) is a tiny hi-fi CD player. Given its minuscule (205 x 37 x 165mm)) proportions it is a wonder that Pro-Ject have not only crammed in a slot-load CD drive, but also a 384kHz DAC to feed the analogue jacks on the back. There’s an infrared remote control too, and an optical digital output for those wanting a tiny transport. At £325 it’s up against some tough (and much larger) competition from a plethora of other makes, but the CD Box S2 has a few tricks up its sleeve.

CD Box S2 Black Front

The CD Box S2 enables 1:1 bit-perfect playback of CDs following the redbook standard. It achieves this by use of a miniature computer controlling a slot-load PC drive, reading CD data into a buffer memory which allows any reading errors to be corrected. This does result in longer startup and reading times, but it’s a small price to pay for the gain in sound quality. The 32-bit, 384kHz PCM5102A DAC offers selectable IIR and FIR filters, the latter requiring more computational power but enabling a finer and linear processing of the digital signal.

The CD Box S2 is packed in Pro-ject’s standard Box Design packaging, nestled in thick layers of foam and supplied with a 9V DC power adapter with a set of universal outlet connectors. Supplied too is a credit card style remote and a coin cell battery.

The remote is perhaps my least favourite part of the deal. It feels nowhere near as substantial as price rivals, the buttons are identical in size and arranged in a grid so are difficult to easily locate until you get used to it, and it isn’t the kind of quality handset that should be supplied with a component at this price.

CD Box S2 Silver Front

Build quality of the CD player itself, however, is vastly superior. Its aluminium casework comes in black or silver and is well put together. Rubber feet help to prevent unwanted movement and provide some isolation from the supporting surface, not that the S2 is especially sensitive to vibration.

On the front is the display, CD slot and some simple transport controls – next, previous, play and stop / eject. There’s also a standby control with LED to show the unit’s power status. The remote gives access to a far greater range of programming controls as well as direct track access, volume controls for a Pro-Ject amplifier and a control to toggle between the digital filters. On the back, you’ll find RCA analogue output jacks, an optical digital output and a DC power input.

CD Box S2 Silver Rear

Operation is simplicity itself. Once connected up, a press of the standby button initialise the drive. The CD Box S2 supports CD, CD R and CD RW discs, which are slid label side up into the front slot. It can also play the CD layer of a hybrid SA CD as is to be expected. Once a disc is inserted the initialisation process begins which takes an average of about 35 seconds as the drive whirs and grinds away. The player does make a noticeable amount of noise in operation, so if you have a silent listening room and are likely to be disturbed by the sound of your CD player’s mechanics this might not be the player for you.

The S2 does have a few software quirks; perhaps the most irritating of which is its inability to handle fast sequential button presses. You can’t, for example, skip quickly through a disc using the transport controls, nor can you press stop twice quickly to stop and eject the disc – you must wait a few seconds between presses, or the player won’t register the second press. It also didn’t always allow skipping to all tracks on a disc on the first play.

On my first play of the Shire’s 2015 ‘Brave’ album for example, the player wouldn’t let me skip any further than track 9 of 11. I let the disc play from track 9 and it continued to play the remaining tracks without fault, and thereafter it would happily skip between all tracks. Ejecting and reinserting the disc didn’t reproduce the problem, so I can only assume the software made an error in calculation as it loaded the disc’s table of contents. I also encountered a few occasions where the player would stop for no apparent reason or skip within a track, especially if it had been left in pause mode for a minute or two. It was almost as though it had run up against the limits of its buffer memory, and would miss a second or two as it pulled fresh data from the disc. None of these affect he experience playing discs from start to finish, though they do make an otherwise excellent player somewhat frustrating to operate and there are many players around this price that aren’t nearly as finicky, if at all.

One of the challenges Pro-Ject faced in designing of the original CD Box S was simply an issue of fitting an audiophile CD player in a case that really isn’t much larger than that of a portable machine, and barely larger than a couple of stacked dual cases. At the time, this was achieved by carefully selecting a minimal number of integrated devices to provide the desired functionality, including a DAC intended for use in portable devices and a somewhat compromised digital filter. Here however the internals have been refined and are now driven by a mini computer allowing 1:1-bit accurate CD playback and a far better 32-bit, 384kHz DAC with vastly improved digital filters. Output voltage is up too, rising to a more standard 2.1V.

This results in some impressive specifications, not least a 20-20,000Hz frequency response flat to within 0.15dB. It is therefore difficult to describe the sound of the CD Box S2 as it is, unlike many players around this price, quite neutral in character. A vanishingly low 0.005% (1kHz) distortion specification helps here too, as does a signal to noise ratio of 110dB over the full 20-20K frequency range. These specs are impressive at any price and add up to a very fine sounding player indeed. Stereo imaging is excellent, levels of detail across the board are high, and the CD Box s simply gets on with the job of showcasing a recording as it was intended to be heard. Simply put, it plays what’s on the disc. Feed it with a good recording and you will be rewarded with a sense of musical satisfaction that makes you forget about the hi-fi and focus more on the content. This is no mean feat, and that a sub-£500 CD player with the compromise of being so tiny in stature can achieve such performance is quite remarkable.

This miniature CD player is a departure from the norm and there’s no doubting its exceptional performance, both technical and musical. There are a few quirks in its software which could likely be resolved with relative ease. Finicky software does diminish the value of this otherwise excellent player, though not enough for me not to recommend you have a listen. In reality the player only displays its personality once in a while, and its performance is so good that I’m tempted to excuse the occasional glitch. If Pro-ject can tweak the software and include a better remote handset in the box (a must at this price), this would be a serious contender and is very much worth an audition.

By Ashley

I founded Audio Appraisal a few years ago and continue to regularly update it with fresh content. An avid vinyl collector and coffee addict, I can often be found at a workbench tinkering with a faulty electronic device, tweaking a turntable to extract the last bit of detail from those tiny grooves in the plastic stuff, or relaxing in front of the hi-fi with a good album. A musician, occasional producer and sound engineer, other hobbies include software programming, web development, long walks and occasional DIY. Follow @ashleycox2


  1. I have a question about this unit. I’ve tried playing several cds from my collection (mostly box set material with enhanced features) and the ones that are enhanced cds don’t play back; I keep getting a text on the screen that says “data disc” and it immediately ejects it. Why does this happen?

    1. Likely because it’s picking up the enhanced portion, designed to play in a computer, and assuming it’s a data disc because it doesn’t conform to the Redbook standard. Certainly an interesting point though.

  2. Great review! Have one myself and have never had any software glitch. Firmware v1.05. But I will keep an eye of that. Wonder if it is possible to update firmware in some neat way (burned binary file?).

    1. Thanks! Forgot to check the firmware revision on the review sample, I presume it would have been an early production unit and thus may have been running a prior version. Good to hear yours is running without fault.

    1. Thanks! I will ask for a sample of the Head Box, might be a couple of months as there is a fair bit of content scheduled at the moment.

      1. Hi. Thinking about one of these or maybe the CD Box DS, any thoughts?
        I’m going to be running it through my Loewe Tv system so are both ok with inter connects as I’ve got about 7m to travel.

        1. Providing you use decent quality cables (not audiophile BS but not bargain basement) either should be fine. If I were choosing between the two I’d buy the DS

          1. Thanks for that. I was going to get the Audioquest Tower connects unless you can recommend others? It all started off as wanting something simple to play my CD collection on through my surround system. I was going to get a blu ray but got put off by the terrible quality issues so the cost has somewhat escalated! Do you have any other suggestions of a quality brand but small simple machine?

            1. Terrible quality issues? A decent blu-ray player should be perfectly adequate for playing a CD through a surround system. That said, have a look on eBay for a suitable length interconnect using Van Damme cable. In terms of small CD players, Marantz and Yamaha both make a small player, though admittedly not as small as the CD Box. The CD Box is about the smallest.

              1. I was looking at the cheap Sony blu Ray players but there seemed to be lots of reviews about quality issues and the unit having a very cheap build quality.
                Out of curiosity, why do you recommend the DS2 over the S2?
                It’s getting confusing online now as there seems to be new versions of both.

                1. Some of the cheap blu-ray players are a bit crap in terms of build quality, you do get what you pay for. A decent one however should be fine. I’d recommend the DS2 over the S2 due to it having a better CD mechanism, better electronics and generally better build quality throughout. Be mindful that the DS2T model is a transport only and thus requires that your receiver have a digital input via optical or coaxial.

                  1. Hi,
                    These are getting above what I wanted to spend. What are your thoughts on the older DS model over the new S2 ?

                    1. It’s an excellent player. Very similar if not identical drive to the DS2 if I recall correctly and nice digital conversion hardware.

                    2. Great thanks. Last question. I was told I couldn’t run a digital cable over 5m in length which limited my options. Is this correct

                    3. It’s best to keep them as short as possible. However if you buy a decent shielded digital cable, something that looks nice and thick (something made with Van Damme cable for example or intended for professional install use) it should be fine. Coaxial cables are better for longer runs as you’re transmitting a stronger electrical signal rather than an optical one. But with a decent cable you shouldn’t have any problems over 5 metres. I’ve never tested myself to see exactly how far a Digital audio signal will travel, however this video is a good and thorough demonstration of how robust a digital signal is.

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