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By and large, I have not been impressed with the sound quality in many recent CD players. These new players have appeared with claims about the benefits of technologies like higher sampling rates and optical interstage coupling. Nevertheless, their sound has seemed to plateau out or even to degenerate in quality.
Although other reviewers disagree, I have been disappointed in particular with most of the machines using the new Philips 16-bit, four-times oversampling system. For all the hoopla from the various manufacturers who convert Philips-based electronics, most of these models have not sonically outperformed the earlier 14-bit Philips -based machines, and many have fallen behind the latest generation of Sony and Yamaha machines. While the various Philips 16-bit players I have heard have differed in the details of their sound character (as well as front-panel features and brand names), they all have been characterized by a slight hardness and low-level grittiness in the upper midrange. This increases the artificiality of most music and contributes to listening fatigue.
This brings us to the Mod Squad Prism, a $1,300 player intended to be representative of the current state of the art. Like many high-end players, it is a conversion of a machine supplied by another manufacturer. In this case, the Prism is a converted Philips CD473 that uses the same Philips 16-bit D/A circuitry I have just complained about.
Nonetheless, it is the first real advance in CD sound that I have heard recently.
It also demonstrates that an engineer who emphasizes sound as well as technical quality can make a tremendous improvement in audible performance.
Steve McCormack, the chief "Mod" of the "Squad," is understandably reluctant to explain all the details of the changes he has made in the Philips CD473. He does believe, however, that the Prism differs fundamentally from most other high-end conversions in that the company has made significant changes in the digital circuitry as well as in the analog circuitry. He feels that this allows the Prism to get the maximum possible lucidity and transparency out of a CD with minimal loss of musical information.
It is clear that the Mod Squad has done far more than change a few minor components. There are major changes in the D/A section of the motherboard as well as a totally new board with a new audio gain stage, power-supply regulation, current-summing amplifier, and filter circuitry. The Mod Squad has added an inboard power supply for all of the new analog circuitry but has left the Philips 473's original power supply to handle the digital and motor circuitry. They have damped the 473's transport mechanism and the chassis, developed a damping disc to match the transport's characteristics, and completely removed the headphone amp circuit.
Whatever the actual details of the technology, the sonic results are striking. The Prism is significantly more open and dynamic than any other player I have heard to date. It delivers the dynamic range that CD has promised since it first appeared.
It is interesting to compare the Prism to a top-quality conversion of a Philips 14-bit player like the Sonographe. If you listen to a high-quality disc like Jazz at the Pawn Shop (Proprius CD7778/9) on each player and set the volume to provide the same measured output levels on a medium-intensity passage of music, the Prism will provide substantially more dynamic energy in the loud passages and substantially more resolution of harmonics and low-level sound. The same is true of a comparison with the older Cambridge CD player, the recent Sony top-of-the -line machines, and several others.
It is important to note that the Mod Squad Prism does more than simply make CDs sound more dynamic and improve the musicality of the upper octaves. Given at least a 24-hour warmup and using the supplied damping disc, the Prism consistently provides more musically convincing detail with percussion, strings, and woodwinds than any other player I've heard to date. It also does a better job of resolving complex organ passages and choral music. In fact, for anyone who loves choral music or opera, the Prism should, perhaps, be compulsory. Vocal details that smear into the background on other machines are significantly clearer on this player.
As for frequency response or timbre, the Prism has the merit of being remarkably flat and neutral. If you like popular music or jazz, you will be very pleasantly surprised by the quality of the bass line. The Mod Squad player restores a lot of bass power without exaggerating bass output. Its superior dynamic performance is comparable to, or better than, that of the best moving-coil cartridges.
The Prism has superior upper midrange and treble. Most high-end players soften the upper octaves, particularly the upper midrange. The Prism takes a very different approach. It removes most of the hardness and "grunge" in CD sound without losing upper-octave speed and energy, and it offers the most musically realistic reproduction of low-level treble "air" and detail I have yet heard in a CD player.
I should, however, stress that this is not a "forgiving" player. While other players-all in very different ways-reduce some of the sonic shock effect of poor or mediocre CDs, the Prism gives you all the data on the disc. To give some specific examples, The Mod Squad player's superior resolution can be a real blessing with CDs that are good re-masterings of older recordings, or where the producer really knows what he or she is doing. Anyone who admires the Chesky remasterings of classic records is going to love this unit. The same will be true of anyone who admires the string sound of Reference Recordings, or jazz and voice on the better Opus and Proprius CDs. If you like the way Harmonia Mundi treats its vocal recordings and Bach, you are going to want the Prism. At the same time, it is merciless in revealing the essentially nonmusical results of close miking. You clearly hear the fact that the mike is too close or that the instruments are spotlighted in ways you will never hear in a live performance. The strange fascination many producers now have with the sound of a violin as heard at the violinist's chin is all too clear.
Some of the same advantages and disadvantages occur in terms of soundstage. The Mod Squad Prism can overcome the slight two-dimensional sound character of CD, and it is more revealing of soundstage detail than any other player I've heard. This superior soundstage performance comes through quite clearly even on a popular-music disc like Willie Nelson's Stardust (Columbia CK-35305). You will get better definition of imaging and soundstage width than with any other player yet developed. The Prism has a deeper apparent soundstage than any other player I've heard except the conrad-johnson--and the Prism puts more musical detail in that depth. Just sit back and listen to any given instrument on Jazz at the Pawn Shop. Not only do you get a musically convincing placement, you get more apparent focus without any artificial "etching" or exaggeration of imaging effects.
You may, however, feel differently if you put on something like Linda Ronstadt's Greatest Hits, Volume I (Elektra 1062). While Rontstadt scarcely turns into a 15-foot wandering violin, the overall effect on about half the tracks makes one wonder what the producer thought he was doing with the soundstage. One of my sons occasionally listens to Abba, a group that was cursed, during its early and middle career, by some of the worst recording efforts in the history of the business.
The Mod Squad Prism clearly reveals that Abba's backup on its Greatest Hits (Atlantic 19114-2) is often recorded in a way that I can only describe as stage-wide, mono, time smear; it seems to have been filtered to remove the deep bass and any localizing information above 2 kHz.
The Prism presents the producer of a recording with the same challenge posed by many of the best new moving-coil cartridges. There is no forgiveness in terms of errors in the soundstage. With good chamber music and jazz recordings, the Prism will provide a far better illusion of realism. With bad recordings, the extra resolving power can be jarring.
You really do need to set your balance control to provide the best soundstage with a given recording. As is the case with all other top-quality players, the Prism is very revealing of the minor imbalances in right-left signal information in CDs.
If I had to go out and buy a player today, I'd buy the Mod Squad Prism. I have to stress, however, that I am talking about the nuances you hear with top, high-end equipment. There is a long list of other new high-end players coming onto the market, and a number of other firms have their own high-end conversions of the Philips 16-bit machines. If you buy this player, do so because it produces excellent musical sound, not because it comes with any guarantee of being top of the heap.
If a competing designer is to make a major advance over the Prism, that designer will have to combine the best of digital sound with the best of analog.
The Prism has solved the problems of lucidity and apparent dynamic range in CD to a degree where depth, air, and transparency are the remaining barriers. Further, I should remind you that while the Prism does cost $1,300, no one ever said good sound should cost only pocket change. (While earlier there was an upgrade service for the CD650 and 472 models, the Mod Squad no longer converts other models.) In a world where high-end tonearms can cost over $2,000, the Mod Squad Prism CD player offers a hell of a lot of sound quality for the money.
-Anthony H. Cordesman
(Source: Audio magazine, Aug. 1988)
Also see: Magnavox CDB650 CD player (Mar. 1987)
Mission PCM-7000 Compact Disc Player (Aug. 1987)
hilips CD960 Compact Disc Player (Jun. 1988)
Philips CD880 Compact Disc Player (Jan. 1989)
Philips LHH 500 CD Player (Apr. 1992)
Philips LHH1000 compact disc playback system (Jan. 1990)
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