Classic CD Player on Philips TDA1541 chip
It so happened that in 1987 the most sophisticated CD-players on the TDA1541 were no longer made by Philips. But if such a miracle of technology as the Sony DAS-R1 is difficult to find now, then for our test we managed to find a worthy little brother CDP-337ESD, which was released the same year and sold at a price of 89,800 yen.
The wooden cheeks and the 20-button musical calendar in Sony players may seem like an anachronism, although in fact it’s a handy thing. And what is outside and inside will leave few people indifferent. Not even a few years have passed since the announcement of the CD, and in the face of the CDP-337ESD we see a very advanced unit that can wipe its nose even with modern CD-models.
The theater starts with the hanger and the CD player starts with the remote control. Japanese developers know how to please people, and not make puzzles for abstract thinking, as it happens with the menu of European manufacturers. The most commonly used group of operations is play, rewind, etc. – equipped with a metallized backing on the RM-D650 remote control. Such little things always warm the soul very much.
The entire spectrum of the CDP-337ESD’s functionality is redundant – all those index scans, cassette pauses and million-track programming. But the main thing is that the remote control has a button for ejecting the CD-tray, so that every time you do not disturb the front panel organs. A useful Eject key and an obvious solution, which for a very long time, until the devices of the 90s / 00s, did not occur to the Philips ergonomics specialists.
Both Sony and Philips used the same Sharp LT022MC readout laser in their drives – only Philips did not use a diffraction grating. In previous articles I praised the CDM0 / CDM1 transports, but this does not mean that the others were grazing geese at that time.
Structurally, the Sony KSS-190A (formerly BU-1) of die-cast aluminum with a brushless motor, floating suspension and linear movement of the pickup truck on magnetic rails impresses with its monumentality and precise response.
It was the KSS-190A that was installed in the same CDP-R1 and a number of Accuphase players. The read speed of the KSS-190A is almost instant.
The beginning and the end of the work is accompanied by a short dull sound, as if you gently hit the surface with your knuckles – that’s all. No more signs of CD drive operation are noticeable: no rustling, chirping, grunting – just silence.
The total weight of the unit is 12.5 kg due to the unprecedented efforts to protect the CDP-337ESD from vibration. Plastic can be seen here only on the optical output plug. The frame-beam structure of the body uses a double steel plate and a layer of felt at the bottom and top, as well as rubber.
Double suspension with elastic gel, signature anti-magnetic chassis in Gibraltar imitation marble, glass fiber reinforced. Unlike the rumbling Philips rattlers, everything here – from the controls to the KSS-190A drive – looks neat and works as delicately and quietly as possible. Even the slot for the tray is insured with a rubber shield to eliminate acoustic penetration between the room and the interior of the player.
Such troublesome and even extravagance in the mechanics of CD-players in the 21st century have not been encountered. And this applies not only to the High End desks, which, in principle, are too tough for those processing machines that audio electronics concerns can afford. But in the future, Sony itself behaved much more modestly on its top-end ES series players than it was in the 80s.
The CDP-337ESD power circuit is built on independent power supply of 11 systems to separate the noise from the servo and analog circuits. Naturally, the filling contains respectable components: for example, Elna Duorex 35V / 6800μF and Nichikon Muse, located on a solid epoxy board. But most importantly, why we are gathered here today is, of course, Philips TDA1541A.
The CDP-337ESD has two such chips, but unlike the TDA1540, each of them works as a stereo converter. Actually, that’s why on the Sony tray with some slyness and inscribed “4 x DAC”, i.e. four lines of digital-to-analog conversion.
Thus, our pair of TDA1541 does not take over the left and right channels, but works in parallel – each with its own stereo stream. And then the final signal in a checkerboard pattern is fed to the adder and calculated for greater accuracy (the manufacturer declares it up to 18 bits).
Index “A” in the new TDA1541, which appeared in 1988, indicated the possibility of using 8x oversampling at 352.8 kHz (which was done by the Sony CXD1144 digital filter) – in contrast to the old TDA1541, which allowed only 4 frequency of 176.4 kHz.
The CXD1144 is a three-stage FIR filter with a ripple response of ± 0.00001 dB and a 120 dB attenuation. Now everyone has become fans of NOS, and in the 1980s, fans of this business would be looked upon as illiterate.
Actually, the very first Sony players, including the portable D-50, worked without oversampling, which had to be replaced by a very tough analog low-pass filter that spoiled the sound. Now something similar is being fended off by NOS apologists, who are afraid to damage the dynamics of the ultrasonic component. History goes round and round. And digital filters with oversampling were the first to appear with Philips.
And this simple solution, which allowed a more delicate analog filter at the end of the chain, was adopted by other audio manufacturers in the 80s. The ability to digitally process the signal at high rpms was highly valued, and is still respected by Chord.
After all the transformations, the signal goes to the 3rd order analog filter and then to the JRC 5532D operational amplifier for line output. A separate JRC 4556D op amp is used for headphone output.
Also, headphone level control will be duplicated on one more pair of RCA outputs, labeled as Variable. All this can be controlled from the remote control, and the player itself can be connected directly to active speakers or a power amplifier.
The rear panel also has digital outputs (optics and coaxial) that can be disabled. However, I must admit that I did not pay attention to them, since I was primarily interested in the sound capabilities of the TDA1541A installed in the CDP-337ESD.
Anyone who previously found the TDA1541 to be too soft will be put to shame by the CDP-337ESD sound. In principle, this is what new digital sources are counting on and striving for, but they rarely succeed in staying in harmony. Fitted appropriately under the supervision of Sony, the 1987 CD player sounds just like a “healthy man’s Saber”, not a “smoker’s Saber.”
The CDP-337ESD demonstrates unprecedented detail in every musical line with rich timbre texture. And not a single detail escapes: there is a feeling of being traced by a thin chisel and the visibility of the needle eyes in music. Continuing the lexicon of allegories, the sound comes out the same as the work of the mechanisms of Sony – at the same time fast and precise and soft. An iron hand in a velvet glove.
And this is not a dead texture of details. It feels like the rich details in the path give a rich sound. One cannot remain indifferent to this presentation – cheap equipment does not sound like that. And it will not sound, do not count on it, lovers of Chinese boxes with beautiful dimensions and empty sound.
The CDP-337ESD breed is heard right away, from the first chords – even at the headphone output, which is usually put into players on a leftover basis, but not in this case. True, the measured output impedance at the output was 100 ohms with a maximum level of 4.4 V without load. However, when connecting a low model of crime or distortions, I did not notice. And for 300-ohm headphones here you get quite suitable 65 mW.
The frequency response demonstrates a strict straight line, deviating at the very end by only 0.1 dB. This is a Sharp cutoff type with 8x oversampling. And the digital filter CXD1144 itself, of course, works according to the phase-linear profile – with a symmetrical “ringing” before and after the pulse.
The distortion spectrum is clear and generates no harmonics in the audible range with a 1 kHz test signal. That is, they lie below –100 dB. Of course, this does not mean that there will never be harmonics on a real music signal.
But this is the established procedure for THD control – apply 1 kHz and watch harmonics. A similar picture was at the regulated output. That is, the level reduction was performed in the analog domain, and not in the digital one, as with some components of those years.
Thus, the level of distortion of the CDP-337ESD did not depend on the decrease in the signal volume. The signal-to-noise ratio changed only slightly, which is quite expected. So Sony’s regulated output can be easily connected to an external power amplifier.
It is also worth noting the noise immunity of the circuit – 50 Hz power pickups, which are almost always noticeable when using an unbalanced connection, will not creep into the audio spectrum. Good job.
When taking measurements, an interesting detail was observed. You can see that the noise level has “worsened” to -93 dB, although the overall dynamic range of the path remains “normal”: -98 dB.
In all likelihood, this is how the noise shaping system works to better distinguish low-level signals. Indeed, at such values, the general background of the tract does not change at all by ear, even in headphones, where it is usually easier to notice the background of rest. But at the same time, the contrast of sounds is felt – and the pauses become “expressive”. I don’t know, thanks to this noise shaping trick or the magic of the TDA1541. Although, of course, there is no trace of 18-bit resolution (i.e., an indicator above 108 dB).
With the noise overloaded to zero, the TDA1541 behaves in the same way as all other converters – it responds with the growth of the noise shelf in ultrasound. But it was not possible to measure the jitter of the device, because the KSS-190A transport could not correctly read the 11,025 kHz signal recorded on the CD-R.
This is not to say that the device does not play such media at all (although it does not have to). After all, the rest of the test tracks on the same CD-R were read correctly enough not to damage the measurement results. But the KSS-190A may have certain whims – for example, there was a reluctance to read the table of contents (TOC) even of some branded disks. God knows why. Maybe they don’t like modern 80-minute CD-matrices, which do not correspond to the old Red Book for a long time. Or maybe the copy protection system that was supplied with one of these CDs interfered.
And the most important question: how did one of the highest implementations of the TDA1541 perform in comparison with the Philips players of the first, second and other generations? Which one to prefer? And at this point, I shut up, announcing the upcoming review-comparison of various devices with Philips TDA chips. That’s where we compare, we’ll see.