Accuphase DP-80L CD player & DC-81L digital processor
Before turning to the answers to those questions, let me tell you a tale. A friend of mine back in the UK finally gave into temptation a couple of years back and bought a Ferrari. It wasn't new, of course, but it was a beautiful car, Pininfarina-designed; I suppose you could call it a two-door sedan, to distinguish it from the hairier mid-engined Maranello machines. A year or so back, when I was visiting the old country, my friend was taking my wife and I for a spin in his dream car and asked if I would like to take a turn behind the wheel of the beast.
Would I? What would you have said?
Actually, I felt equivocal: bending the bodywork of one's friend's Ferrari is a surefire way of terminating that friendship! But drive it I did. Yes, you could buy a lot of Hyundai Excels for the price of such a car, even quite a few Mustangs. And an Excel will certainly get you to the same place via the same roads as will a Ferrari. But I am here to say that it is not the same experience. You may drive ordinary cars; with a thoroughbred like that Ferrari, driver and car take on a symbiotic relationship, the tires becoming the extension of your nerve endings. The car both is responsive to your wishes and feeds back all you need to know about the road and your relationship with it; it is almost as if you need only think about what line you want the car to take, and the deed is done (footnote 1). That Ferrari redefined my attitude to driving. No, I will never be able to afford one myself, but I am glad to know that it exists.
The only possible justification for high price, therefore, is that you get more, not only than you expected but also than you knew existed. That is the only standard by which to judge human artifacts designed without compromise, and it was only with that finally clear in my mind that I addressed myself to the subject of this review.
The Accuphase DP-80L CD player and DC-81L digital processor are refined versions of the original DP-80 and DC-81 that I reviewed for Stereophile in Vol.10 No.6. That $8000 player featured a 2x-oversampling digital filter and discrete 16-bit DACs and had what was then the most accessible CD sound that I had heard. Even that well-known digiphobe Larry Archibald was moved to praise its sound. It didn't quite approach the resolving power of the original Stax Quattro, however, which was, in those far-off daysSeptember 1987the champ when it came to the retrieval of detail.
Identically styled and sized to the original '80/'81 combination, with champagne-gold front panels and highly lacquered persimmon wood endcheeks, the new units are very different under the skin. The player is based on a diecast aluminum chassis and now has a sprung transport, compared with the original's unsprung unit, and is capable of playing 3" discs. A hinged panel conceals all function buttons, apart from Play, Track Search (Back/Forward), and Pause. All the functions, including Open/Close, are duplicated on the supplied infrared remote control. The power supply is hefty, based on a large toroidal transformer at the unit's rear, and includes a line filter on the mains input.
A single large printed circuit board carries all the circuitry responsible for controlling the disc motor and linear-drive laser sled, for extracting and demodulating the data from the disc, and for presenting it in the EIA-standard, multiplexed, two-channel serial format to the output sockets. (Two optical outputs are provided, as well as a 75 ohm coaxial output.) Sony LSIs handle the servo control and digital processing tasks, and two 8-bit microprocessors are used, one each for mechanism control and for display/control key handling, with a single master clock used throughout the player. A discrete red LED numeric display indicates play, track/index number, and time, though, as with the display on the processor unit, this is a little too discreet, being hard to read from the other side of a sunlit room.
The equally massive DC-81L features separate toroidal transformers for the digital and analog sections, again with intrinsic mains supply filtering. A hinged flap on the front panel conceals digital source select and level up/down buttons, these duplicated on the DP-80L's remote control. Red LEDs display which of the optical or coaxial inputs has been selected, the sampling frequency of the input signal, whether or not the input is pre-emphasized, and the amount of output attenuation selected, in dB down to 40dB. Four main printed circuit boards, in two layers, almost completely fill the unit's interior. On the bottom are the digital and power-supply boards, the latter carrying the rectification and filter circuitry to provide separate regulated 5V rails for the digital circuitry and left and right DACs; left and right regulated 37V rails for the DACs; independent regulated ±19V supplies for the left and right analog boards; and a 24V rail for the relays.
A block diagram of the processor reveals that the digital board takes the input datastream, identifies the sampling frequency, and automatically reconstitutes the correct clock frequency32, 44.1, or 48kHzusing a phase-locked loop. Error correction is applied if necessary, and the data for left and right channels are separated and resampled by a digital filter operating at 352.8kHz. This is specified as giving 110dB attenuation between 24kHz and 328.7kHz, with less than 0.0001% ripple in the passband. The digital filter also applies the appropriate de-emphasis (with an accuracy said to be ±0.001dB!) and adjusts the output level digitally. (This is done by multiplying the digital word representing the analog sample value by a coefficient selected by the volume up/down buttons. For example, to reduce the level by 20dB, each digital word would be multiplied by the coefficient 0.1.)
Whenever mathematical operations are carried out in the digital domain, the result is always a digital word with more bits than the original. This therefore has to be truncated somehow, and as simply chopping off the extra least significant bits reintroduces quantization noise, this must be done with some sophistication, rounding off rather than rounding up or down. The Accuphase therefore uses a noise-shaper circuit to accomplish this task, truncating the filter's internal words to 20 bits. The final stage on the digital board consists of two arrays of serial-to-parallel converters; the two sets of 20-bit-wide parallel datastreams, together with a "deglitch" signal per channel, are then taken via an edge connector to a mother board.
This, in turn, leads to the two analog boards, one per channel. These are shielded magnetically and electrically and each is also electrically isolated from the digital-processing board by 21 optoisolatorsexpensive, high-speed Hewlett-Packard devicesone for each bit and one for the deglitch signal. Finally, we get to the heart of the system, the D/A converter which, as in the original DC-81, is a discrete current-multiplying device. The '81L's DAC, however, is a 20-bit device, which implies a resistor tolerance of an astonishing less-than-one-part-in 219; ie, less than 0.00019% error! This, I suspect, is where a significant proportion of the DC-81L's cost liesand how do you even measure that you have trimmed a resistor to that degree of accuracy unless you already have an accurate 20-bit A/D converter?
The deglitch signal controls a sample-and-hold circuit, followed by a current-to-voltage converter. The analog output voltage is then processed by an 18dB/octave Butterworth low-pass filter to rid it of the 352.8kHz sampling frequency components and their multiples, this based on a GIC (General Impedance Converter) circuit; separate unity-gain buffers, constructed from discrete transistors, provide balanced and unbalanced outputs from XLR and RCA sockets respectively. No DC-blocking capacitors are used, the output buffers featuring DC-servo circuitry.
All things considered, the Accuphase player is built to an outrageously high standard and will probably outlast its owner, as indeed it should at this price level.
So, what was the Accuphase combination's sound like?
In a word, superb.
"Superb," along with "excellent," "good," and "wonderful," is, as I tell other writers for this magazine when I'm wearing my editor's hat, a word conveying almost no meaning. I should expand on this adjective, therefore.
Tonally, the Accuphase is less thin than the sample of the Theta DS Pre that I auditioned, even taking into account the latter's de-emphasis error. It is slightly more forward than the Sony DAS-R1, however, with which it shares an awesomely deep bass, even with subwooferless Celestion SL700s. By comparison, the CAL Tempest II, while true to the musical aspects, is rather unsubtle in the upper midrange and altogether more untidy in its rendering of orchestral tone colors.
Footnote 1: That Ferrari is the only car I have ever driven that actually felt more secure on the road above 100mph than below. (At double-nickel speeds, you're not giving the tiger anything on which to chew.) This is assuming that the roads are empty, of course. A lasting conclusion from my experience with this car was that the English roads are not good enough for it, even the freeways being too crowded to allow it room to breathe. But on the empty roads within the body of France, or on those in the USA's desert Southwestlong straightaways, interesting curves, and no trafficdriving such a car to its limits, or at least to the driver's, must be the nearest thing to winning Wimbledon, beating Alain Prost for the checkered flag at the Monaco Grand Prix, and having your first symphony premiered by the Chicago Symphony all in the same year.