Stereo Amplifier

Review: Sony CDP-337ESD CD-player

If you see the 337 alongside the 557 you will have some difficulty identifying which is which; indeed they share the same instruction book and remote control handset, and the mechanical layout, large parts of the construction and the proffered facilities are identical. However, the price of the 337 is only a little over half that of the senior model and the weight about two-thirds; and there lies the clue-the power supplies and signal processing circuits are considerably less complex in this cheaper machine and the metal casework is less e1a borate. I have always considered the Sony CD player mechanisms as the ones by which others must be judged and certainly their ES models are not, in my experience, equaled elsewhere. As a passing recommendation, I recently heard of a CDP-101 110 volt model, bought in Japan before they were available over here in late 1982, which was eventually put into continuous daily use, locked in the repeat mode, as a programme source in a factory test set-up. It has never been serviced and I was told, rather laconically, that they put a different disc in it (they only had three!) about once a month "when everyone was fed up with the tune". So much for those scaremongers who solemnly informed us that the lasers would only last a few hundred hours. The current ES mechanism is even more robust and has the added advantage of very fast operation. It is also extremely stable, being thoroughly insulated from external disturbance, both physical and audible; this insulation also ensures that the unit operates in complete silence.

The very comprehensive illuminated display includes Sony's Custom File facility, enabling you to programme tracks or index points on up to 226 memorized discs and write a ten-letter (or number) description which will be called up as soon as any one of these discs is inserted. I was amused to find that a certain disc (which I must not name) had been got at by persons unknown and now displayed the word Rubbish. A full range of more normal control options is provided, some of them only available from the handset; these include Sony's motor driven line output level control, which also sets the headphone level.

Although it lacks the copper-plated double skin construction of the 557, the 337 has a stout coated steel chassis with a slide-on steel cover which rests on four internal rubber damping pads. There is a single skeleton power transformer behind the mechanism; a scattering of small printed circuit boards are fixed adjacent to terminations or controls, but the majority of components are on a single large glass-fibre board occupying the right hand half of the area. Much of this is taken up with the power supplies, disc handling, servo and display components; the filtering, conversion and audio sections are confined to the right rear quarter. The digital filter is Sony's own, first seen in the 557, and produces an 18-bit, eight-times oversampled stream of data which is as near ripple-free as makes no difference; i.e. not accompanied by self-generated false pre and post artifacts which upset the timing. However, in this case it is not fed to the expensive 18-bit linear DACs used in the senior model but to a pair of Philips TDA1541 dual 16-bit converters with their outputs paralleled but their inputs fed from alternately clocked data to ease any possible embarrassment at being asked to sample at double their normal accomplishment. In effect each sample is evaluated twice and the joint decision passed on. The resultant audio signal is relatively free of supersonic switching effects and thus requires, and gets, only very simple analogue filtering. That this unusual arrangement has been incorporated in order to permit the "eight-times oversampling, 18-bit digital filter" claim in the literature rather than to further any sonic advantage is debatable, so I will not pursue this unworthy thought.

Measurements made on the 337 did not quite equal those made on the supremely accurate 557 (which has caused me to update some of my test gear and to dream up modifications for other items when I can find the time). It did, however, produce a set of first rate results, only two items requiring comment; the output, of correct and linear phase, checked out at 2.2 Volts, almost 1dB above specification (this has been seen on a number of machines lately) and the low level output was compressed by about 5dB (or nearer 4dB on the above error), i.e. - 90dB signals were raised to - 85dB. I am not sure of the significance of this but it may possibly have some influence on the listening tests in view of the fact that the 1987 16-bit, four-times oversampled 555ESD, which remains my personal preferred machine overall, is one of the very few which consistently checks within 1dB of the correct level on these very low level signals, and it may just be that our hearing mechanism is more affected by this than we know or have in the past assumed.

Whereas the current top model 557 left one with an impression of sagging involvement due to some unexplainable neutered reaction to its endeavours (which someone has suggested might be due to deficiencies in its audio circuits), the 337, so similar in many ways, reverses that theme. If anything it is over-active, giving the music a more dramatic presentation than one sometimes feels to be genuine. On the whole it provides a more interesting performance which is, in my judgment, to be preferred. At its substantially lower cost it must be considered Sony's current best buy, sharing as it does much of the build quality and all the superior operating facilities of the senior model.

However, it still lags the 555 to my ears and it is of interest to consider how, because this is entirely subjective and nobody has to believe it- all I ask is that they listen carefully. The most obvious difference is that on direct switched comparison the 337 gives one the impression that it is slightly louder, no matter how carefully one has checked the levels. Concentrated listening suggests that this impression comes from some form of ornamentation of the lower middle register which shows up on woodwind and horns, rather like the effect often associated with multi-microphone pick-ups. I particularly noticed it on the recent EMI recording of Nigel Kennedy with Jeffrey Tate and the ECO, playing the Bruch and Mendelssohn concertos ( CD CDC7 49663-2, 1/89). This was recorded in Abbey Road Studio No. 1 and, apart from the effect noted above on the otherwise clear recording, there is an excessive amount of bowing noise which the 337 latched on to. There was nothing to complain of in the frequency response though; both extremes are excellently portrayed and the violin tone of Perlman in his Bach solo release (EMI CD CDS7 49483-2, 12/88) is a real revelation.

A fine machine, then, just short of the best sound which I know Sony can achieve but excellent value, with all the facilities and that feel of solid quality which has marked all their ES products.