hy would anyone today, in the second decade of the 21st century, in the time of audio files and the demise of physical media, need a CD player? The question can be answered directly, without any philosophizing: in order to play CDs. That, however, immediately raises another question: who the hell needs CDs anyway? This cannot be answered in one sentence. And the answer will not be unequivocal and binding – each time it will be more of a personal statement containing opinions, convictions and faith in certain phenomena of the person you ask. Here is MY answer.

After “Positive-Feedback.com” published a report of the Krakow Sonic Society meeting dedicated to the comparison of various CD editions, I received a lot of different questions, not at all as kind as those in the previous paragraph. They came from angry or sometimes amused readers for whom the very act of focusing on CDs does not make sense, not to even mention comparing them. Their position is that the only thing worth listening to is high resolution audio files or SACDs (see HERE). The other group obviously involved analog record and tape recorder enthusiasts who believe the whole discussion about digital audio as such to be pointless. The CD is in this unfortunate position that it is cornered between the past, which by coincidence and through vinyl enthusiasts’ persistence slowly becomes the present, and the future, in which all digital data, free of physical attributes, immaterial and preferably high-res, is stored in the “cloud”. One and the other portray the CD as a limited format, archaic at the time of its launch, which due to its user friendliness and the powerful lobbying of music companies enjoyed an incredible success that has not been and will not be repeated ever again by any other format. In other words, people have been deceived.

It is therefore hardly surprising to see the euphoria of those manufactures that from the beginning claimed that vinyl sounds so good and the CD so bad that we should not bother with the latter. That was the position of Linn, Naim, Rega, but also Audio Research. The latter is the only one that never manufactured turntables or their components, but it has “always” offered phono pre-amps. Its conviction about the superiority of analog formats over digital formats lasted so long that the first Audio Research CD player, the CD1 from 1995, was offered only a few years ahead of the market launch of high-definition discs: SACD and DVD-Audio (1999 and 2000 respectively). And how much self-awareness and self-criticism you need to call your player “reference” ten years after your first such design! Most high-end manufacturers build their “reference” (at least in theory) product immediately in their first year of business operation. AR didn’t offer a Reference line CD player until 2005 when the Ref CD7 was launched. Three years later came the Ref CD8 and in 2013 the Ref CD9 that is the subject of this review.

We’ll find in it everything that the Plymouth-based manufacturer has been known for. It is a top-loader, like all previous Audio Research designs, with a tube-based analog section. It employs 6N30P tubes I am very familiar with, e.g. from Ancient Audio CD players and the Loit Passeri. The 6N30P is a dual triode, originally Soviet- and now Russian-made. The analog section power supply is built on two more tubes, a powerful 6550WE beam tetrode and another 6N30P. This circuit has been tried and tested repeatedly to great effect in this manufacturer’s preamplifiers. The player sports the proven Philips CD Pro2R drive and can be used as a transport, with digital signal accessible through the AES/EBU and BNC outputs. I find it hard to imagine why anyone would do something like that; a much more likely scenario is to use the CD9 as a DAC. Its rear panel features four digital inputs: asynchronous USB 2.0HS, AES/EBU, RCA and Toslink. All of them are 24-bit, 192 kHz capable. To start using the USB input you need to install an appropriate driver on your PC. It can be found on a CD-R that comes with the player, but can also be downloaded directly from the manufacturer’s website and turns out to also support the Reference DAC.
This is no coincidence as the D/A converter section design is directly based on what AR engineers learnt by the reference DAC and the DSPre. What they used here is two stereo DAC chips in dual-mono configuration with two separate clock oscillators – one for the 44.1/88.2/176.4 sampling-rate family and the other for 48/96/192 kHz. We can also choose one of the two digital filters, “slow” or “fast”, with or without upsampling. .

Albums auditioned during this review

CDs

• ABBA, Gold - Complete Edition, Polar/Universal Music Japan UICY-91318/9, 2 x SHM-CD (2008).
• Dire Straits, Brothers in Arms, Vertigo/Universal Music Ltd. Hong Kong 5483572SX, SHM-CD/XRCD2 (1985/2011);
• Et Cetera, Et Cetera, Global Records/Long Hair LHC00071, CD (1971/2008).
• Ivie Anderson, Ivie Anderson With Duke Ellington & His Famous Orchestra. 1932/1940, EPM 157352, “Jazz Archives No 42”, CD (1991).
• Judy Garland, Over The Rainbow, Going for a Song GFS236, CD (?).
• Kombi, Kombi 4, Polskie Nagrania Muza/Polskie Nagrania PNCD 999, CD (1985/2005).
• Kombi, Nowy rozdział, Polskie Nagrania Muza/Polskie Nagrania PNCD 985, CD (1983/2005).
• Mel Tormé, The legend of Mel Tormé, Going for a Song GFS360, CD (?).
• Mills Brothers, Swing Is The Thing, Trumpets Of Jericho Ltd/History 20.3039-HI, “The Great Vocalists of Jazz & Entertainment”, 2 x CD (?).
• Perry Como, Perry Como’s Song Collection, Going for a Song GFS284, CD (?).
• Savage, Tonight, Extravaganza Publishing/Klub80 Records CD001, “25th Anniversary Limited Edition No 59/150”, CD (1984/2009).
• Sting, The dream of the blue turtles, A&M Records/Mobile Fidelity, UDCD 528, gold-CD (1985/1990).
• Suzanne Vega, Nine Objects of Desire, A&M Records, 540 583 2, CD (1996).
• Tommy Dorsey, Masterpieces 15, EPM 158342, “Jazz Archives”, CD (1995).
• Wolfgang Dauner Quintet, The Oimels, MPS/Long Hair LHC59, CD (1969/2008).

Hi-Res audio files

• SATRI Reference Recordings Vol. 2, Bakoon Products, FLAC 24/192.
• Al Di Meola, Flesh on Flesh, Telarc, 24/96 FLAC, Ľródło: HDTracks (2011).
• Charlie Haden & Antonio Forcione, Heartplay, Naim Label, 24/96 FLAC, Ľródło: NaimLabel.
• Dead Can Dance, Anastasis, [PIAS] Entertainment Group, PIASR311CDX, "Special Edition Hardbound Box Set", CD+USB drive 24/44,1 WAV (2012);
• Depeche Mode, Delta Machine, Columbia Records/Sony Music Japan SICP-3783-4, FLAC 24/44,1, Ľródło: HDTracks (2013);
• Miles Davis, Tutu, Warner Brothers Records, FLAC 24/96, Ľródło: HDTracks.
• Persy Grainger, Lincolnshire Posy, Dallas Wind Symphony, dyr. Jerry Junkin, Reference Recordings, HR-117, HRx, 24/176,4 WAV, DVD-R (2009).
• Sonny Rollins, Tenor Madness, Prestige, WAV 24/96, Ľródło: HDTracks (1956/2012).
• Stan Getz & João Gilberto, Getz/Gilberto, Verve, 24/96 FLAC, Ľródło: HDTracks (1963/2012).
• Stardelay A New High Fidelity, Ozella Music OZL22006CD, FLAC 24/44,1 Ľródło: Linn Records (2008).

Japanese editions of CDs and SACDs are available from

Collecting special CD editions, searching for rare and unique titles, bargain hunting on CD Japan and eBay must be one of the coolest, most fulfilling hobbies I know. Regular contact with music, continuous education, gaining experience and the joy of owning a physical, a beautiful object is a unique experience. Fun guaranteed for life. In the words of Mieczyslaw Stoch, the owner of the largest collection of vinyl in Poland: “Money is not a value in itself. It is a means to get things you love. That seems cool to me. Collecting things also expands our horizons and does not bring us down. It gives a sense of freedom. No need to go to the concert hall to listen to the best performance of your favorite music pieces”. While he refers to black discs, the mechanism is the same and so is the end goal – music. “The collector has no doubt that vinyl is the most fantastic music media devised so far. Among other things, it is very durable. But there are many more advantages. In this day and age when speed is everything, we slowly lose our humanism and. I think it was Wojciech Mann who once said that the analog record is more human. I agree. Vinyl has retained a certain softness, spaciousness of the sound, and friendliness. The analog sounds generate the calming alpha waves. And from what I heard neither plants nor animals respond to digital sound – he said in TOK FM” (see HERE).

CD albums

Among the thousands discs I own most are still normal “plastics”, or regular CD releases, which used to fill all music stores when they were part of every town’s landscape. My collection includes a number of old and very old recordings, released by specialist labels that reissue recordings whose copyright has expired, usually in the form of disc compilations. Judy Garland, Andrew Sisters, Bing Crosby, Vera Lynn, early Sinatra, Ivie Anderson, Tommy Dorsey, Mills Brothers, Perry Como, Mel Tormé and many, many others. The necessary remaster of the source material, usually restored from shellac discs, is carried out in the analog or digital domain. The system that is commonly used for this purpose is CEDAR. I have a continuous problem with these albums – few CD players are capable of handling them. Interestingly, no media player so far have played any single one of them (as CD rips) satisfactorily enough to make me want to listen to it from beginning to end. It’s more than just the sound. It’s about something irritating and annoying, as if someone shoved a finger into my eye, making me retch and instead just switching off playback. I have never had such problem with analog records containing the same recordings or recordings from a similar period, even if technically they seem even weaker than their digital remastered versions. Analog enthusiasts will be quick to declare that it is quite common and normal because digital media in general are irritating. Audio files apologists will, however, claim that the problem lies with the Compact Disc and its limited resolution and frequency range. I will offer another suggestion: the players that we normally use cannot apparently handle this type of distortion. And I know for a fact from personal experience that the CD is capable of sounding at least good, and sometimes simply phenomenal. There is always something for something, especially if we are talking about low-cost components, but the vindication of this format has recently significantly accelerated and things will only get better.

And what’s the Reference CD9 got to do with all that discussion? Well, it simply is one of the four or five CD (and SACD) players that are capable of playing the albums I’ve mentioned above and make them sound similar to what they do on vinyl. The others are players from: Ancient Audio, Mark Levinson, EMM Labs and, among the less expensive, Human Audio. That’s not to say that others are rubbish. They have numerous advantages and often sound excellent. It’s just that their designers concentrated on improving other characteristics than those I have discussed. In the case of Audio Research and other players that are similar in this respect to the American machine, the focus has been on conveying coherence and liquidity, resulting in a smooth, coherent and holistic sound. Another characteristics are the lack of treble harshness and a warm, smooth and absolutely non-irritating upper midrange. This trinity defines the CD9 sound and puts it in a league that’s not particularly crowded. It does not mean that this is the best CD player in the world. My only, or perhaps main, point is that it is a player that plays CDs – but also audio files, more about which later – in an absolutely and uniquely smooth and non-irritating way. That alone should draw to it the attention of those who regard the digital medium as a plague, or those who are looking for a “final solution” for their CD library. The Audio Research under review may indeed be something like that. It has its weaknesses and a clearly programmed own “sound”, but in what it does well it does it brilliantly.

Its sound is shaped similarly to other components from this manufacturer. I could actually quote entire paragraphs from my reviews of the Reference 5 SE preamplifier or the Reference 75 power amplifier and it would be just fine. But since CD playback draws our attention to slightly other sonic aspects than signal amplification does, and we interpret them differently, I will resist the perspective – however tempting – of using “copy and paste”.
The tonal balance is shifted towards the lower midrange and upper bass. The attack is slightly rounded which makes everything sound friendly and deep. This is helped by excellent vividness with lots going on among larger bodies and sound planes. The sound creates a great first impression that lasts longer and holds our attention even after many hours of playing. I say ‘after many hours’ as the AR encourages long listening. It is not pushy but consistent in doing that.
As I said, its tonal balance is shifted downwards. It was mostly audible with classical recordings with vocals recorded in a large space – e.g. Ramirez’s Misa Criolla. José Carreras sounded a little thickened as if he were further away, and the soundstage was even greater than that I know from other presentations. There is no problem if the recording is a little dry and lacks the bottom end, like Tosca performed by Maria Callas, and those albums will actually sound better. However, if everything is in its place, we get a lower, deepened perspective. As noted earlier, there is nothing for free and that’s the price we pay for the absolute distancing of the Reference CD9 from the digital realm.

Perhaps that’s why I spent most time with other recordings. Quality components somehow direct our hand that reaches for the albums to play. With the AR I listened primarily to the above mentioned albums recorded in the 1920s-1940s, to the rock from the 1970s to 1990s and to discs recorded by Polish artists. The American player did with the latter the kind of wonders I had never before experienced with the digital medium.
Take, for example, the albums Nowy rozdział and Kombi 4 by the band Kombi. Released in in 1983 and 1985 respectively, they bear all the blows once taken by the Polish phonography. Their sound is rather dry and shallow. This often renders the rich arrangements completely invisible while the flat perspective kills the tension between space and color. The CD9 does a sort of “remaster” of this type of albums. The sound is richer, more vivid and set primarily on powerful, deep bass. The recordings sound more balanced overall.
However, it is not only Polish albums that suffer from this type of ills. Listen to Abba, and you will hear the same thing. Disco target of most quartet’s recordings, short production deadlines as well as a fairly relaxed attitude to the sound quality resulted in most albums by the Swedes, the winners of the 1974 Eurovision Song Contest, sounding horrid. No matter what treatment they underwent and how they were released. As usual, vinyl records are privileged in this respect, which is the advantage of this format. Yet even the SHM-CD version sounds light and lifeless. The difference between the latter and well-produced CDs is dramatic. It will be much smaller on the CD9. I will say more – it makes for a pleasant listen, without paying attention to the technique nor seeking what lies behind the presentation.
There are other albums that will sound exceptional on the AR. Generally, each disc will play very well, as I already said, but some will get a second life. So will be with Sting’s The Dream of the Blue Turtles and Dire Straits albums, especially Brothers in Arms. The former was recorded on analog equipment, the latter on digital, yet both sound somewhat flat and lifeless on the CD. I have their best digital releases I know – Sting on Mobile Fidelity and Dire Straits on SHM-CD XRCD2 – but some things just cannot be overcome. Played back on a regular CD player they will sound correct or perhaps even good. The American unit, just as previously with Polish discs, brought out what’s best in them, revealing fantastic arrangements, color and complex texture. It mostly benefited the guitars – really great! – but the bass (which is understandable) and drums also sounded meaty.

Digital audio files

My description of the Audio Research Reference CD9 player will be incomplete if I don’t say anything about its playback of audio files, especially via the USB input. The machine plays CD rips or CD-quality files downloaded from Linn Records, Naim Label or HDTracks very similarly to CDs, but ultimately I have preferred the physical medium. While the USB input provides a deep and warm sound, the CDs will be slightly more open and resolving, which happens to be of value here. After all, it is a Compact Disc player. The difference will not be striking, though, and if someone has a large collection of CD-quality recordings on the hard drive, they will be a joy to listen to. What’s more, however “non-kosher” it sounds, MP3 files were also very, very nice… And so we have reached the gutter. Bouncing back towards the stars, however, and to high-res files we immediately ride the rising currents. With this type of signal the CD9 sounds not only vivid and dense but its tonality is also more linear. As if hi-res files didn’t need the additional support of a stronger bass. In absolute terms, the difference between the CD and hi-res was not large enough to be able to talk about qualitative leap. The reason was that the physical media sounded so convincingly, so good that a better depth, more balanced frequency response and slightly clearer treble of the 24-bit signal did not turn anything upside down. They had, however, their own value.

Digital filters and upsampling

Like any high quality digital source, the Audio Research player offers the capability to shape its sound. It is limited and nothing extravagant, granted, but still. First of all, you can use upsampling. This technique was first introduced to the audio world in the 1990s to immediately gain immense popularity. In short time, audio components without upsampling were treated as defective. In retrospect, we can see why. In theory, each component in the signal path introduces additional distortion. It is also true in the case of digital circuits. However, sometimes it is worth sacrificing something to get something else. Such additional component that became DAC’s integral part was the upsampler. Its role was to convert the input signal sampling frequency from 44.1 kHz (CD) or 48 kHz (DVD) to 96 kHz and then 192 kHz (that refers to an asynchronous upsampler; the much less common synchronous upsamplers converted the signal to a multiple of the basic frequency: 44.1 kHz to 176.4 kHz, and 48 kHz to 192 kHz). The upsampler also extended the word length from 16-bit to 24-bit, which was something of an extra function. After all, it’s a Sample Rate Converter and the name obliges. The sound quality improvement it brought resulted from two things, one of which used to be considered major (also by me) and the other was usually passed over in silence. The first was to feed the DAC a pre-processed signal with the highest parameters it was able to handle. That way the DAC was spared the additional internal processing that was carried out in the preceding circuit. The second issue related directly to jitter. Upsampling, whether asynchronous or synchronous, consists in signal re-clocking. That was, it seems, the main value of upsamplers. Re-clocking allowed to improve the signal precision and thus reduce jitter. Pretty soon the problem of signal clocking has been widely noticed and given a lot of attention, like using separate oscillators for the two sampling-frequency families with their own dedicated power supplies, and other techniques. A player that does not exhibit high jitter reacts to upsampler differently than other players. In addition to the above solutions, the Ref CD9 also features a separate digital filter that re-clocks the signal reducing jitter to the very low value of 10 ps. Hence, switching on the upsampling here rather changes than improves the sound. Everything gets tighter and more focused, with improved sound definition. However, the natural softness and lower midrange body disappear and they are key for the CD9. Hence, I auditioned the player with the upsampling off.
We also have an option to change the DAC output filter. Without going into details, the signal in the D/A converter must be properly filtered. Without that, there will appear additional distortion that was not originally there. The filtration can be carried out in various ways. The Burr Brown chip used in the CD9 allows us to choose between the “fast” and “slow” filter. Without a shadow of a doubt, the latter results in a more natural sound, although from a technical point of view it is inferior as it generates higher distortion.

Conclusion

Audio Research continues to do its own thing and even the change of ownership in 2008 did not disrupt anything. The Reference CD9 is another step up on the once chosen path. Hence, we are not talking here about a revolution, breakthrough, etc., but rather about continuation, polishing and dotting the “i”. The sound is a dense, warm, with the accent shifted towards lower midrange. The CD9 handles digital signal in a special way, eliminating from it what is commonly associated with digital technology: treble impurity, harshness and nervousness. The only nervousness we can experience with the reviewed player is reaching the album end and needing to swap it for another. There is so much old, already known music to listen to and so many new CDs to unpack… This is more of a friend than a tool – with all the benefit of inventory. The resolution and selectivity of, say, dCS players is an order of magnitude better, as is the ability to separate individual planes on the soundstage of Ancient Audio and Mark Levinson players. However, the top AR player from its Reference Series has something that no other CD player I know seems to have: the freedom to reproduce any material in a way we would like to hear it on LP. There are some cons to it but the pros far outweigh them. The built-in digital inputs, most importantly including USB, are a valuable functional addition that is necessary in the 21st century. It is a machine for years, made to easily survive the passing of time and sounding so well that no temporary audio fads or “inventions” will wipe the smile of the face of a music lover who has purchased it.

There is no confusing Audio Research components for anything else. Their aesthetics, worked out years ago right at the beginning of the company’s existence, referring directly to lab or recording studio equipment, has proved timeless. That’s a rarity. What we have here is a large aluminum enclosure with two handles mounted to the front panel. This is taken directly from pro audio racks, where the handles are used to slide the component in and out of a large rack cabinet. Here they just serve as decoration and they serve it well, indeed. The large front panel features green display, green LEDs and silver drive operation buttons. The display is a classic type for the transport used and is sold bundled with the Philips CD Pro2R drive. It is small and assigned to the drive. It cannot be used to display other information, such as digital input sampling frequency or the bit length. The latter data is not available to us in any case, but the sampling frequency is indicated by a vertical row of LEDs right next to the display. It is a pity that AR did not use here the display featured in its preamplifiers. The second row of LEDs shows the selected input (or the CD drive), and the third row is used to indicate the currently selected digital filter, power-on and upsampling-on. The latter is synchronous. While the choice is infrequent, it is well-grounded as the necessary signal processing is significantly easier than with asynchronous upsampling. 44.1 kHz and 88.2 kHz signals are upsampled to 176.4 kHz and 48 kHz and 96 kHz to 192 kHz. The USB input is treated differently with only basic frequencies being upsampled – 44.1 kHz to 88.2 kHz, and 48 to 96 kHz.

The CD9 is a player featuring balanced analog stage. Consequently, it offers balanced XLR as well as unbalanced RCA analog outputs. The latter are particularly noteworthy. Although they bear the AR logo they look like they were manufactured by CMC (Charming Music Conductor) and are really very good quality. Digital input RCA connectors come from the same manufacturer and are found right next to three other inputs: AES/EBU, Toslink and USB. All accept signal up to 24-bit and 192 kHz. The USB input is of the asynchronous 2.0HS type. While nowadays it is an increasingly less necessary function, the CD9 can also be used as a transport. Hence the presence of digital outputs: BNC and AES/EBU. They are always active and I have found no information whether they can be disabled.
The disc is placed directly on the motor shaft or rather on a plastic “cup” mounted to it, under a manually sliding door. We press the lightweight aluminum disc. The disc’s TOC is loaded after closing the door. Opening it automatically stops playback.

This is not a machine with interior full of air that plays the lead role. The entire space is tightly packed with circuits, mainly due to the use of a tube-based analog section with dedicated tube power supply. Both the I/V conversion section and gain/buffer stage are tube-based. They employ the large 6N30P dual triodes from Russian Sovtek. The two tubes in the power supply come from the same manufacturer and are the 6550WE beam tetrode and another 6N30P. I don’t see any coupling capacitors between the tubes in the signal path. We find Wima coupling capacitors in the output and RealCap and MULTICAP filtering caps in the power supply. The power supply is very complex. I counted six secondary windings of a very large R-core transformer as well as many large filtering capacitors and integrated voltage controllers. The power supply and analog circuits are mounted on a large circuit board bolted to the bottom of the enclosure. The side featuring the transformer is mechanically decoupled with dampening material under the board. Vibration isolation seems particularly important to Audio Research engineers. All electrolytic capacitors feature damping material; so does the underside of the top panel. The 6N30P tubes sport rubber rings to reduce microphonics.
The digital section is mechanically and electrically isolated from the analog stage. It is mounted on a small separate PCB bolted to the rear and side panel. At the input we have a Burr Brown SRC4391 frequency converter. It is followed by two Burr-Brown PCM1792 stereo D/A converters, one for each channel. It is these DAC chips that allow built-in digital filter selection. Both channels work in each of them in parallel. The USB input is handled differently. Its PCB is plugged “upside down” to the main board. That allows for easy future upgrade. The circuit is based on a Cypress Perform CY7C68013A. Next to it is another integrated circuit, programmable Xilinx Spartan FPGA along with two master clocks, each for one of the sample-rate families. The company literature claims that signal from all sources is re-clocked to minimize jitter. I would bet it happens here. All electrical digital inputs as well as outputs feature impedance matching transformers. The CD drive is mounted to a large T-shape profile, machined from an aluminum block. The drive is bolted via springs, which come complete with the whole set.

The remote control looks old-fashion, just like the component itself. It takes some skill to operate it as the buttons are close to each other and are quite small. In addition to the basic commands for the drive, the remote can be used for input and digital filter selection, switching on the upsampler and darkening/disabling the display.