Once again, Im reviewing a CD player at the tail end of its retail life. This one is still listed as current; in fact, it's more or less the flagship of the Philips line, the Philips LHH1000 being no longer available; however, all Philips-made high- end equipment will from now on be sold under the Marantz label (as it has been in Europe), and the Philips LHH50O will be quickly phased out.
All that would be more of a reviewer’s dilemma if I could muster any enthusiasm for this high-priced product, but l just can't. I have considerable respect for Philips technology —only a fool wouldn't— but the Bitstream Philips LHH500 isn't one of their best efforts.
Structurally and cosmetically, the unit is a one-piece version of the two-piece Philips LHH1000, very solidly built on a die-cast aluminum alloy chassis, with a gold finish that intends to look expensive. Control functions and ergonomics are first-class, as long as you're willing to use the remote control even when the main unit is at your elbow, since only the most basic buttons are duplicated on the front panel. What's disappointing about the Philips LHH500 is the circuit design and the Bitstream DAC 's measurable performance. The discontinued Philips CD-80, costing 60% less, is actually a more desirable piece of equipment.
The master-slave power supply ofthe Marantz CD-80 is missing from the Philips LHH500, and in place of the DC servo of the Marantz CD-80 we find an electrolytic capacitor, not even film- bypassed. (At $2000!) The differential to single-ended converter is similar to the circuit used in Sony l-bit CD players. This circuit requires the op amp in it to reject significant amounts of high-frequency common-mode signals. The NJM5534 op amp used in the Philips LHH500's differential to single-ended converter doesn't have good common-mode rejection at high frequencies.
The Bitstream DAC system in the Philips LHH500 doesn't even come close to state-of-the-art performance. I measured -l dB gain linearity error at the -80.77 dB level in the right chainiel and -4.7 dB error at the -90.31 dB level. The left channel was only a tiny fraction better. That means we’re just about down to li-bit resolution, which is obtainable with almost any cheap player. My THD readings confirmed the low-level nonlinearities.
The DAC chip used in the Philips LHH500 is the SAA732l, which was not designed for high-end applications and creates the need for an expensive kluge to implement the complete DAC circuit. The SAA7220 digital filter (also used in the l6-bit CD-80) replaces the internal digital filter of the SAA732l to reduce the passband frequency ripple at the output of the latter. To achieve fully differential opera- tion, fourteen SSI chips are used in conjunction with two SAA7321 chips. This is an expensive method to obtain a fully differential DAC output and contributes to the high cost of the Philips LHH500, which doesn't seem to be justified by the measurable results. To say something positive, on the other hand, this is one of the best units I've tested as far as RF is concerned: there was hardly any coming out of the left channel and none out of the right channel.
The relatively poor value and impending obsolescence of the Philips LHH500 gave me very little motivation to ag0nize over it in elaborate ABX liste11i11g tests. Let me just say that, on music, I noticed no difference between it and other expensive players. It appears that 15-bit resolution d0esn't sound obviously faulty.
Now for the good news. The Philips LHH500 will be superseded by a Marantz player in which the Bitstream DAC will be the SAA7350. This chip, which represents a significant advancement over the SAA7321, was discussed in the article by David Rich in Issue N0. 15. Since then, Philips has introduced an important new chip to be used in conjunction with SAA7350. The new chip is the TDA1547; its function is to replace the analog section of the SAA7350. As explained in Issue N0. 15, the analog section of the SAA7350 was compromised by the CMOS processing technology used to manufacture the chip. The TDA1547 performs all of the analog signal processing fomerly performed within the SAA7350, but it uses a +/-5V ppwer supply and an advanced analog process that combines npn: bipolar transistors with complementary MOS devices. True 18-bit performance is claimed when the TDA1547 is used in conjunction with the SAA7350, and the combinati0n —which will be used in the new Marantz player— promises to be competitive (and then some) with the top-of-the-line offerings from Burr-Brown, Analog Devices, and Sony. David Rich expressed to me the hope that the analog section ofthe new CD player will be designed by the same team that did the Marantz CD-80 and not the group responsible for the Philips LHH500. If you can't wait to buy a Philips-designed CD player, the Marantz CD-80 at a closeout price is a possibility worth looking into.
The Audio Critic, spring through fall 1991, Issue no.16
