IN our July 1985 issue I drew attention to an announcement by Philips of new mechanisms and integrated circuits for CD players which, together, promised high performance machines at reasonable prices. At that time I little thought that nearly a year would pass before this new lineage of players would arrive in the market place—neither did Philips, but there's many a slip. . or, in our context, a sizeable gap between prediction and production. However their magic 'buzz' words, like "16-bit four-times oversampling" and "digital filtering", aroused new excitement in the contributors to other magazines, who had already developed a soft spot for Philips models as they were probably the ones which sounded most like their fondly tweaked turntables.
In fact, it is perhaps doubtful if any of these new bits of technical verbiage and the undoubted advances they represent have any significant effect on the sound you hear; rather they simplify the designer's job, not least by increasing operational safety margins and—once into mass production—keeping down costs. No, most deficiencies in the eventual sound of CD players, as in other pieces of electronic equipment, stem from more mundane things like power supply stability and isolation, avoidance of clutter from the RF and digital parts of the circuit, diligent attention to earth returns, ungenerous or inept design in the audio stages, and general good housekeeping in the way that wires are dressed and interconnections organised.
Regrettably, in the event some of these futuristic integrated circuits which the Philips engineers had dreamed up proved very difficult indeed to get into production, and one gathers that a return to the drawing board had to be made on quite a few occasions. It was not until the end of May that a trickle of early production machines went out to the press and then, most unfortunately, my sample CD650 produced a disappointing performance. This proved to be untypical, and was eventually, traced to an earthing fault, but it wasted some days. Soon after I managed to get it performing correctly, the cheaper model CD450 arrived to confirm what I had by then succeeded in establishing; from the most important aspect of sound quality, Philips have entered the ranks of the top performers with these new machines.
The performance of these two models is basically identical, and they only differ in physical size and the operational possibilities that they offer. The CD450 is a 'midi' sized player, 320mm wide, and is relatively basic. The only feature over and above that offered by the majority of machines is the provision of remote control. This is accomplished by the now usual infra-red light transmitting handset, and readers might like to note that a similar facility is now available as an optional accessory to the CD150 reviewed by JB in the January issue. Once the disc is loaded, all normal functions can be carried out either at the machine or by remote control, except for one curious anomaly. If you want a disc to repeat ad infinitum, you can accomplish this only by command of the remote control; there is no repeat button on the machine itself. The illuminated 'state of play' display provided is simple but adequate, and the usual control buttons enable one to progress or retrace track by track or to search at three progressive speeds. In addition, one can set up a programme of required tracks on a disc in any order and up to a maximum of 20 entries.
The CD650 is a full size machine, 420mm wide, and it has quite a lot to offer, both operationally and electronically over its cheaper brother. Dealing with the electronics first, there is a separate internal headphone amplifier fitted with its own front panel volume control, and an additional pair of audio outputs. The normal output pair gives what Philips call 'pure' analogue sound; i.e. the frequency response is flat to within the limits of measurement over the quoted range of 2020,000Hz. Before reaching the other pair of output sockets, labelled 'Additional Filtered', the left and right signals pass through a quite complex additional amplifier involving two integrated circuit stages, with frequency selective feedback over them, and a pair of transistor buffers. Philips say this gives "a warmer analogue output as a result of extra filtering; you can use whichever you prefer". On measurement, it allows the top octave to tail off a couple of dB and does very little else. Audibly it softens the sound, as one might expect, and the whole idea seems on the face of it to be an expensive and unnecessary pandering to the subjective assessment critics. However, as a top Philips man (who requested anonymity) explained, "several manufacturers have made a lot of money doing similar things to past Philips models with the aid of those same subjective assessors, so why shouldn't we get in on the act?" Touché.
The additional operational features provided on the CD650 are considerable, in one case unique, and they are centred on a fold-out numeric keypad normally concealed at the right side of the front panel, above the headphone jack and its volume control. First of all, this allows one to start with a particular track, or even at an index number within a track, with a minimum of effort and concentration, for the illuminated display has its indications extended to guide you along. A little more effort (you have to remember to press one button twice) will enable you to start at a selected time within one second. Other little niceties are also now to be found on the main control panel; Repeat, A to B repeat, Scan (ten seconds from each track) and a selector switch enabling you to limit play to a single track, to insert a four second pause between tracks (an invitation to copy discs on to cassette recorders with the AMS facility?) and auto pause which holds at the end of a track until the Pause button is pressed. The novel feature which I have not used before is FTSfavourite track selection; this enables one to make a choice of desired tracks from a disc and instruct the machine to memorize that choice so that, if you want to repeat your selection at a future date, just touch the FTS button before play and only your personal sequence will be repeated. There is enough memory built into the machine to cope with an average of five tracks from up to 150 discs. The remote control handset provided with the model CD650 is more elaborate than that of the CD450, allowing all the features except FTS to be operated from your armchair.
The internal construction of these machines shows how Philips manage to achieve these standards of elaboration and performance at such a modest cost. There is extensive use of plastics; all the casework except the, lid and front panel, practically all the mechanism including gearing and slides for the disc access drawer and innumerable smaller parts, are all plastics. Everything clips and slots together; there are a very few selftapping screws but no nuts and bolts. Printed circuit boards are of moderate grade, double sided, and make extensive use of the latest minute surface-mounted components, held to the board by tiny spots of glue and then immersed briefly in the molten solder bath. Interconnection is by uncoded multiple leads, with selfconnecting plugs which cut through the insulation and cold weld to the special grade of wire on assembly. Low consumption devices are employed where possible to keep down the size and cost of the power supply components. All of this has certainly paid off in terms of immediate perceived value, and only time will tell if the long term prospects are as promising as the more substantial and considerably more expensive equivalent performers from Jaan.
There are one or two interesting connection facilities provided on the rear panel of these machines, apart from that extra pair of output sockets on the CD650. First of all, a six-pin socket permits the connection of a separate receiver for the infrared remote control, in case the player has to be used in a situation where its own 'eye' cannot easily be reached by the wide beam from the handset. A further socket carries a digital output in the standard agreed format suitable for future use with CD ROM, for graphic displays etc. and for digital sound processors. Connecting this socket to the only one of the latter devices to come my way so far, the Sony DAS702ES (see January issue) produced an exactly similar performance to Sony's own companion piece the CDP552, except for some peculiar behaviour of the 702's muting relay when playing discs with pre-emphasis. (As a general rule, discs of European manufacture are not emphasized, Japanese ones are: every player contains circuits which automatically compensate.)
On their own, both the CD450 and CD650 came extremely close to emulating the performance of the £2,000 Sony pair. Just little subtle things now and again caused one to wonder if they were a little less well achieved but, on sound alone, I would certainly not like to make a decision in a blind test. Of course, in this expensive company, both the Philips machines were outstripped from the mechanical and engineering aspects, although they give reasonable speedy access and generally perform in above-average fashion. They were also good in their ability to deal with some of the cruelly treated discs which have been around my test bench for some time. Even major scratches were passed with a protesting crack like a similarly marred LP (the Sony just blanks for an instant) and from this aspect these two fared better than some models of the cheapest Philips CDI5O which I have had through my hands and which refuse to track these same discs at all, although they incorporate the same mechanism.
I went through the usual measurements with regard to frequency response, crosstalk, signal-to-noise ratio, square-wave response, etc. All perfectly OK and therefore boring; I shall not bore you with them. Let me sum up by saying that these new 16bit Philips machines are on a par soundwise with the best I have found, perform quite adequately if a little noisily and, if they do not quite achieve the longevity of some of the very expensive competition, so what; you could buy a second one and still have change in the bank.