Audio Research Reference CD9 CD player/DAC

Now entering its fourth decade, the Compact Disc player seems to have reached a stage of maturity where the best models within a given price range will sound pretty much alike. The technology of the Compact Disc itself is set, its possibilities and limitations are well understood; and the designers of CD players who figure out how to stretch the former and finesse the latter wind up at about the same sonic place (again, for the same price), even if they've taken different routes to get there. What distinguishes these players in the marketplace tends to be not so much their sound quality as their features, and the world of digital audio has expanded in ways that make features very important—some of them, anyway.

And so we have the Audio Research Corporation's Reference CD9 digital-to-analog converter and CD player, which, at $12,999, costs about the same as my Krell Cipher SACD/CD player ($12,000), but is so different in design and function that it offers a good test of my theory on converging sound qualities. In the May 2012 issue, I called the Cipher "a great CD player: the best I've heard in its price range, and the best I've heard, period, in my home system." How does the Reference CD9 stack up? What can each player do that the other can't, and does it matter? What does the very existence of such machines, near the peak price for a single-chassis player, say about the future of high-end audio?

The Reference CD9 is a top-loading player that uses Philips's CD Pro2 transport. The drive rests on a ½"-thick metal I-beam that extends the player's full depth. Four 6H30 dual-triode tubes drive the analog section; a fifth 6H30 and a 6550C regulate the power supply. ARC claims that its use of four digital-to-analog converters (two per channel, each in dual-mono mode) reduces the digital noise floor by 3dB (ie, doubling the number of DACs doubles the signal's amplitude while keeping the noise the same). Power is handled by a custom transformer that, according to design engineer Dennis Petrich, has no gaps or breaks in the material of its R-core and thus more efficiently contains the flux field, with much less leakage, resulting in less distortion and a higher signal/noise ratio. Jitter reduction (to <10 picoseconds, according to the spec sheet) is handled by a crystal-controlled reclocking mechanism.


In its most up-to-date feature, the CD9's rear panel has not only digital outputs but also five digital inputs—S/PDIF on RCA, BNC, and TosLink, AES/EBU on XLR, and USB—for outboard digital devices or digital streaming. (The player comes with a CD-R carrying the necessary driver programs for Macs and Windows PCs.) Once you've pushed a button (on the CD9's front panel or its remote control) that activates one of these digital inputs, you can set the bit rate to 24 and the sampling rate to 44.1, 88.2, 96, or 192kHz, depending on the source signal. (You can also set it to play at the source's native resolution, whatever that may be.) The DACs are also equipped with dual oscillators, so that music at 44.1kHz (or doubled to 88.2kHz or, from there, to 176.4kHz) uses one of the oscillators, while music played at 96 or 192kHz uses the other.

Finally, when you're spinning discs, the CD9 allows you, with a push of a button, to upconvert the sampling rate from 44.1 to 88.2kHz. Another button lets you select the digital filter: Fast (a brick-wall filter at the highest frequency) or Slow (a filter with a more gradual rolloff).

For those familiar with Audio Research CD players, the Reference CD9 is the same as the CD8 (released in 2010 at a price of $9995), except for its digital inputs, the selectable filters and upsampling options, and the circuitry that facilitates them: the four DACs (vs the CD8's two), the two master oscillators (vs the CD8's one), the greater bandwidth of the analog circuitry, and the sample-rate display on the front panel.

I hooked up the Reference CD9 to a system that included the Simaudio Moon Evolution 700i integrated amp, Revel Ultima Studio2 speakers, and Nirvana cables. I usually place Black Diamond Mk.4 Racing Cones under all electronic components and plug all hi-fi gear (except amps) into a Bybee Technologies Signature Model Power Purifier. But David Gordon of Audio Research urged me not to do this, at least at the outset, so I let the CD9 stand on its own Sorbothane feet and plugged its power cord straight into the wall—in my case, into hospital-grade sockets wired to a dedicated 20-amp circuit. He was right: the player sounded a little better without the usual aids.

I played lots of CDs, occasionally pushing the buttons on the remote control to switch between straight 44.1kHz and the same datastream upsampled to 88.2kHz, and from the Fast (brickwall) to the Slow (gradual rolloff) filters. (About my findings on these matters, more later.) ARC recommends 600 hours of break-in; I gave the review sample three weeks of continuous play before settling down to serious listening. I conducted several A/B comparisons with the Krell Cipher. To check out the CD9's digital inputs, David Chesky, of Chesky Records and HDtracks, brought over a MacBook Pro and an external hard drive loaded with Audirvana software and lots of high-resolution tunes from the Chesky catalog (mainly in 24/192, but a few in 24/96), which I compared with CDs and, when possible, LPs of the same titles.

As a CD player, the Reference CD9 was simply excellent. This wasn't a surprise, given Audio Research's track record. What was a surprise—and what takes me back to the proposition at the top of the review—is that it sounded almost exactly like the Krell Cipher, even though the Cipher has a front-loading transport (it's not a top-loader), transistors (not tubes), two DACs (not four), and proprietary circuitry that manipulates audio signals in the current domain (not the voltage domain). Often, two similarly high-priced components may both "sound good" but have different strengths and weaknesses, which in many cases stem from their designers' different preferences or trade-offs. A review that compares two such models generally identifies those trade-offs, weighs the differences, and concludes which player might be better or worse for various kinds of music or taste. Usually, the differences are pretty clear.

Audio Research Corp.
3900 Annapolis Lane N.
Plymouth, MN 55447-5447
(763) 577-9700

volvic's picture

A very well laid out and thoughful review, enjoyed reading it.  The Audio Research has always been one of the best sounding CD players.  Heard it years ago with Verity Audio speakers and Audio Research amplification and still haven't heard anyting that resembles it for its 3-dimensionality.  A shame therefore that CD players seem to be on their way out, but what a great, last machine to own.  Then again this is the same language that was used in the 90's for vinyl so..........

commsysman's picture

This is ridiculous.

Put this $13000 player up against the $1200 OPPO BDP-105, and it will LOSE..

That is why they did not do the comparison, because it would show how obsolete ANY more expensive player is now. OPPO has blown away the competition.

I will bet that this thing doesn't even get a Class A+ rating in Recommended Components, which the the OPPO and AYRE players have had for some time now.

I got rid of my $6000 AYRE C5xe/MP becuse the OPPO BDP-95 sounds better.

I challenge you; MAKE THE COMPARISON.

It is absurd to do an article like this and not make the comparison; just sticking their heads in the sand,,,,OPPO...what OPPO???


Stephen Mejias's picture

I will bet that this thing doesn't even get a Class A+ rating in Recommended Components, which the the OPPO and AYRE players have had for some time now.

The Oppo BDP-105 is listed in Class A of our "Recommended Components," not Class A+. The Ayre C-5xeMP, however, is in Class A+.

The ratings for SACD and DVD-A players are based on how those players sound with their respective hi-rez media, not CD.

wozwoz's picture

Put it up against any medium price SACD player ... say $999 Marantz or Yamaha or even Oppo) that plays SACDs natively (pure DSD to analog converters) and this CD player will be toast, given a hi-rez recording.

tmsorosk's picture

I've heard the OPPO many times and in different systems , I consider it total junk , it should be sold with a pair of ear plugs . 

Fred Kaplan's picture

Some time ago, I did compare the Krell CD player (in the same league as Audio Research) with the Oppo, with an eye toward writing a piece about it. The Oppo is a fine player for the price, but it was a pale shadow of the Krell, in dynamics, tonal fidelity, bass and treble extension, imaging--in every which way. The difference was so great, it seemed senseless--unfair to Oppo--to compare them.

wozwoz's picture

This CD player seems outdated before birth... what kind of audiophile will pay $12000 for a CD player that cannot even play hi-rez SACDs?  Makes no sense. I'm not even sure that CD counts as an audiophile format anymore. In particular, if a recording starts life as a hi-rez recording (DSD or 24 bit / 96kHz), then the CD format necessarily requires throwing out about 3/4 of all the recorded information ... just to fit it onto a CD (which can only hold 700MB).

CD sales might be in decline, but hi-rez SACDs are flying off the shelves. According to the latest classical charts in the UK, 25 out of the top 100 current classical sellers are SACDs ... vastly in excess to the proportion of SACDs in the marketplace. Certainly tells you what people are buying today. 

hollowman's picture

6moons dived into this cdp a bit further:

The digital section is mechanically and electrically isolated from the analog stage. It mounts on a small separate PCB bolted to the rear and side panels. At the input we have a Burr Brown SRC4391 sample-rate converter followed by two Burr-Brown PCM1792 stereo DAc chips, one per channel. It is these DAC chips that allow built-in digital filter selection. Their stereo channels have been paralleled for mono. The USB input is handled differently. Its PCB plugs upside down into the main board for easy future upgrade. The circuit is based on a Cypress Semiconductor CY7C68013A. Next to it is a Xilinx Spartan FPGA along with two master clocks, one for each sample-rate family. The company literature claims that signal from all sources is reclocked to minimize jitter. I would bet it happens here. All electrical digital inputs as well as outputs feature impedance-matching transformers. The CD drive mounts to a large T-shaped profile machined from solid aluminium and decouples with springs.

hollowman's picture

6moons dived into this cdp a bit further:

The coaxial digital input comes from the same source and is found right next to three other inputs: AES/EBU, Toslink and USB. All accept 24/192. The USB input is of the asynchronous 2.0HS type.