Philips LHH1000 CD player
The LHH1000, which was launched at the recent Las Vegas CES, represents the top of that new Philips line. Made in Japan by the Philips-owned company that manufactures much of the product sold under the Marantz brand (footnote 1), the LHH1000 is a two-box CD playercomprising the LHH1001 transport and LHH1002 D/A converterthat is intended to retail for $4000. (The combination preceded, and is identical to, the limited-edition Marantz CD12 that is sold in Europe and Japan.) Included in the price is a fairly large remote control, the LHH1003/RC, withat lasta rational layout of different-sized buttons. This is fully equipped to handle other Philips video and audio products. It can also "learn" the codes used by your other remotes, rendering it the only one you'll need to use.
Externally, the LHH1000 came as a bit of a surprise to these jaded eyes, over-familiar with plain black or brushed-aluminum boxes. Each enclosure is finished in an almost white, anodized finish, with greenish-gray endcaps (made from zinc alloy, I believe) painted with a nubbly, crackle finishan attractively utilitarian styling with shades of military-surplus radio equipment, nicely set off by subdued blue fluorescent readouts. Internally, the units are constructed to audiophile standards. The transport uses Philips's top CDM-1 mechanism, which is fabricated from diecast aluminum, compared with the plastic CDM-4 mechanism which appears in less expensive and less well-specified players. The loading tray, too, which is made from metal, has a reassuringly solid feel to it.
The only obvious front-panel controls are Play, Stop, and Track Select (forward and back). A swing-down front-panel carries all the programming controlsincluding Philips's Favorite Track Selectionand less-often-used playback controls (although I do feel that Pause should be on the main panel). However, as with most CD players, all commands will be most often used from the remote control. The player is fitted with one optical and two coaxial outputs, each carrying the standard, multiplexed-stereo, serial data stream. An adaptor is provided to enable the LHH1001 to play 3" CD singles.
The LHH1002 D/A unit visually matches the transport, with an identical swing-down panel concealing the headphone socket and volume control and the source selection and digital-tape source/monitor switches. Four serial data inputs are provided, two optical, two coaxial, while there are two digital tape loops, again one optical and one coaxial. Inside, the entire left-hand side of the unit is devoted to power supplies, with three potted toroidal transformers feeding a number of voltage regulators and ELNA Cerafine audiophile-grade electrolytic smoothing capacitors. The digital and audio circuits are individually shielded with copper-plated Faraday cages; the castings that comprise the chassis are also copper-plated, and all bolts used to fix power transistors, etc., are copper.
As might be expected, the LHH1002 features Philips's 16-bit, 4x-oversampling D/A chip set, but with the latest version of the digital filter chip, the SAA7220/B (which, as explained by Peter van Willenswaard in last month's "Industry Update," has a revised offset of less than 1%, footnote 2), and the top-grade dual-DAC chip, the "Golden Crown" TDA1541A S1.
A note on this Philips chip: the bottom 10 bits control transistor switches on the silicon die, each bit switching twice as many transistors as the one below it. Thus the 16th Least Significant Bit switches one transistor, the 15th LSB two transistors, all the way up to the 10th LSB which switches 512 transistors. Provided all the transistors carry the same current when turned on, this arrangement will accurately produce a current output from the DAC proportional to the values of the 10 LSBs in the input word. Matching between the on-chip transistors cannot be maintained to an accuracy better than this, however, so the six Most Significant Bits are handled in a different manner. Again, they switch transistors controlling currents, but now the sizes of currents are controlled by resistors. Matching is arranged by switching the current-controlling resistors between each transistor switch at a very high frequency. Any errors in the individual currents controlled by each transistor will therefore be averaged out between all the switches by this "Dynamic Element Matching."
There will still be intrinsic errors in DAC linearity due to the tolerance in the alignments of the various masks during the IC production process. As further fine-tuning of the DACs is not possible, Philips has adopted a grading process to pick out those which offer the best performance. When the finished doped and etched silicon wafer emerges from the semiconductor plant, it carries many dozens of individual DACs. A computer-controlled tester, consisting of 28 needle probes, then connects to the appropriate pads on each raw DAC die, providing power and supplying serial data from a CD player. From what I saw, this appears to be a simple go/no-go test. If a DAC fails to work, the result being no analog music output, it is marked with a paint spot. Automatic machinery then slices the wafer into the individual dies and mounts those that passed the initial test in the familiar 28-pin DIL plastic package. At this stage, the finished TDA1541 ICs are graded by a computer-controlled test station into three classes: R1 (R for "Relaxed") is guaranteed only to have a differential linearity error (DLE) of less than 2 LSBs from bit 1 to bit 16. This grade will be used in inexpensive players and supplied to some third-party manufacturers. The standard grade is guaranteed to have a DLE of within 1 LSB from bit 1 to 16; this is used in Philips's own reasonably priced players. A small proportion of DACs meet a more stringent performance standard, having a DLE of less than 0.5 LSB for bits 17, less than 1 LSB for bits 815, and less than 0.75 LSB for bit 16; these are termed the "S" grade and are stamped with a small crown.
Footnote 1: With the exception of the US, where the Marantz company is owned by the Dynascan Corporation, Marantz in the rest of the world is a wholly-owned subsidiary of Philips. To make things more confusing, the American Marantz company used to buy its products exclusively from the Philips-owned Marantz company. With the exception of the expensive Philips-brand CD players and amplifiers, and their Marantz equivalents, which are made by Philips-owned Marantz in Japan, nearly all other CD players sold under the Marantz, Philips, and Magnavox brands are made by Philips in Hasselt, Belgium or in Juarez, Mexico. Confused? I was.
Footnote 2: The original filter had a deliberate offset built in to move the zero-crossing point of the signal away from the point where all the bits change value at the same time (see Stereophile passim). Unfortunately, this offset was in the same direction as an intrinsic low-level error in the DAC chip, which lead to the 6dB level error at 90dB ubiquitous in the first generations of this chip set.