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Reviewer: Marja & Henk
Financial Interests: click here
Sources: CEC TL5100, Audio Note tube DAC; Philips DVP 5500S SACD/DVD player
Preamp/integrated: TacT RCS 2.0 room control system, modified Audio Note Meishu with WE 300B (or AVVT, JJ, KR Audio 300B output tubes); Moscode HR401; Trends Audio TA-10; Avantgarde Acoustic Model Three [in for review] ; Qables iQube
Speakers: Avantgarde Acoustic Duo Omega; Avantgarde Acoustic Solo in HT 2.0 setting; Audio Note AN/Jsp silver-wired; Podium Sound Podium 1 [in for review]
Cables: Audio Note AN/Vx interconnects; Siltech Paris interconnects; Gizmo silver interconnect; Qunex 75 reference interconnect; Crystal Cable CrystalConnect Reference interconnect, CrystalDigit S/PDIF RCA/RCA and RCA/BNC, Y-cable, Crystal Cable Piccolo iPod to XLR, CrystalPower Reference AC-Eur/IEC CrystalSpeak Reference; Audio Note AN-L; Gizmo silver LS cable. Nanotec Golden Strada #79 nano 3; Nanotec Golden Strada #79; Nanotec Golden Strada #201 nano3 [in for review]
Power line conditioning: Omtec PowerControllers; PS Audio P1000
Equipment racks: Two double sets of Solid Tech Radius; Acoustic System amplifier shelf
Sundry accessories: IAR carbon CD damper; Boston Audio graphite CD damper, Denson demagnetizer CD; Furutech DeMag; Nanotec Nespa #1; Machina Dynamica Magic Box; TacT RCS calibrated microphone and software; Exact Audio Copy software; Compaq server w/Windows Server 2003 and XP; iPod; wood, brass and aluminum cones and pyramids; Xitel surround processor; Manley Skipjack; Boston Audio Design TuneBlocks
Room treatment: Acoustic System Resonators and Sugar Cubes; Gizmo's Harley Davidson cap
Room size: ca. 8.0 x 4.70m with open extension to a 2.20 x 2.40m A/V bay and open kitchen. Ceiling height is 2.50m, reinforced concrete walls of 45cm, reinforced concrete floors and roof of 30cm. Room has on one side a large glass bay.
Review component retail: €3.000/ea. prior to VAT and other country-specific fees

CD isn’t really digital: Since 1982 when Philips and Sony introduced the audio CD, much water went down the bridge, not the least of it over the last few years. The CD was originally marketed as “Perfect Sound Forever”. As we know now, that was rather a bit premature. Admittedly, the medium was handy, shiny and compact from the onset and soon became outright ubiquitous. Still, it was handicapped by a number of drawbacks. Mind you, these drawbacks really only bother the audio version of the medium. The data version fares far better as we’ll shortly appreciate.

The disadvantages for the audio CD are for the most part mechanical. Contrary to popular perception, a CD is not really digital. Under a microscope, a CD shows many wells - lands and pits as they are called. If it were a true digital storage medium, it would show a far more regular pattern. Each pit or land would then represent a true 1 or 0. With an audio CD however, we see something altogether different.

Mind you, the CD developers did an incredible job making the CD platform what it is today. Rumors have it that the error-correction mechanism alone took ten years of development. Now to basics. The audio version of the CD has no room for a data re-read. The design relies on real-time read-once data capture. In case of a serious read error where data is completely missing, the error correction mechanism inserts a "guess" into the data stream to fill in the blanks. If the error is too severe, the correction mechanism capitulates and your speakers produce a ticking sound. Your CD is too badly damaged or filthy. Next.

So if what’s on a CD aren’t zeros and ones, what exactly does represent the analog waveform? For starters, the physical pattern includes only a part of the signal. Next, even that part is a mere representation of the original, not the actual thing. To wit, a CD contains only the amplitude information of the recorded signal. To recreate the signal in its entirety, we also need the time-domain data. We need to know when a signal rises or falls. These are questions the timing or clock information must answer to which forms the X-axis of a music signal’s graphical representation. The audio CD standard assumes a time constant which needn’t be encoded. Incidentally, this also saves disc space. The time component is provided by a fixed clock. By using the same clock frequency during recording and playback, everything is in perfect sync. At each ‘atomic’ tick of the clock, the laser reads synchronized data from the CD. In theory. The idea is beautifully simple but sadly only fit for a perfect world.

And we clearly don’t live in such a world. At Philips and Sony, the joint team of CD developers soon realized that coding the real zeros and ones of a music signal posed real problems. The rapidly changing pattern soon proved to not be recoverable in any reliable way, at least not without extremely expensive methods. One problem was the difficulty in reading correct data when a series of 1 and 0 called a word ended with a 1 and the next word began with a 1. How to tell the transition from one word to the next? The team came up with a modulation technique called Eight to Fourteen Modulation or EFM. In the so-called Red Book standard for CD, it is noted that a word may be 8 bits long and so can represent 0000 0000 to 1111 1111. With EFM, that 8-bit word becomes an equivalent 14-bit word. A 14-bit word is written such that it always contains at least two but never more than 10 consecutive zeros. This modulation results in the fact that information on an audio CD is never shorter than 3 bits and never longer than 11.

It is these bit packages which determine the lengths of the pits on a CD. They are designated T3 to T11 according to their lengths. A CD player reads these longer pits and lands far easier than single bits. The pits on a CD are arrayed in a long spiral sequence resembling an LP’s groove. Besides the T3 to T11 pits, there is room for a sub code to provide laser guidance along this ‘groove’. Another sub code contains motor instructions for speed adaptation After all, a CD does not run at constant speed. When reading near the center hole, the CD spins at 495RMP. When reaching the outer edge, it slows down to 212RPM. This is necessary to obtain the exact constant read speed of 1.2 meters per second.

While reading a CD, a raging stream of pits of variable lengths whirs past the laser reader whose response currents in the light diodes registering the reflections from the CD are completely analog in nature. Each time a pit transitions to a land or vice versa, it gets interpreted as a digital 1. Each time—here’s that clock again—a clock tick registers no transition, a 0 is read. The CD thus contains only symbolic zeros and not singular 1s per se (nor true 0s for that matter).

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