Sony CDP-361 Belt Replacement & Review

Ordinary in its appearance and almost empty inside, Sony’s CDP-361 is more than a flimsy metal box filled mostly with air. Released in 1995, it is a single-disc CD player from the lower end of Sony’s separates lineup. There’s nothing unusual about its features, nor special about its looks or build. But mass production meant that even Sony’s cheapest players shared some of the same components as the top of the range ES (Elevated Standards) series.

Sony Front

In this case, it’s the DAC. Sony’s CXD2565M is a mysterious DAC chip that shows up in a great many ’90s era players, in single or dual configurations. It is a 1-bit DAC with an 8-times oversampling digital filter, but it benefits from Sony’s so-called ‘PLM’ DAC technology which integrates the the master clock into the DAC chip itself. Thus, jitter is removed immediately before the electronic switch, which is the final stage of the pulse D/A converter, thereby reducing sound quality degradation due to jitter.

Sony also implement a 3rd-order noise shaping algorithm, competing with the likes of MASH, the multi-stage noise shaping used in virtually every DAC from Panasonic. MASH consists of a cascade of low-order loops. For example, a first-order loop containing the difference of a second-order loop with its input and output signals subtracted. When you then add the outputs of the two loops in exactly the right proportions, the quantisation error of the second-order loop is cancelled. The overall result is third-order noise shaping, with more idle tone issues and less accuracy as the proportional addition happens in the analogue domain.

Sony uses a single-loop, third-order noise shaper, the operational details of which remain a mystery. It does clearly consist of a so-called ‘DC dithering’, to move the main idle tone out of the audio band when playing silence by adding an offset. But beyond that we know little about what is actually going on inside the chip. For anyone interested, the data sheet is below.

The CD-361 uses KSS-240A laser optics in a Sony loader (naturally), with a dynamic servo controlling tracking, gain, focus and offset. The servo dynamically adjusts the working parameters of the laser to accommodate the disc being played. If your discs are in good condition you should see a longer laser lifetime as the servo tends to be quite conservative and doesn’t stress the optics unless the player is encountering errors.

Sony Mechanism

I was surprised by how little there is in this player. On the back is a simple board with the output sockets, power transformer and a simple unregulated power supply with DC rectification and smoothing. There is no internal fuse, and no discrete standby power supply though the power switch switches the secondary side of the transformer.

Sony Power Board

The servo is beneath the CD mechanism which is itself a nicely made unit. It’s almost entirely plastic besides the rubber tray belt, but the parts aren’t flimsy at all. The tray mechanism is extremely simple too, and not difficult to align if you take it apart to change the belt.

Mechanism Board With Sony Chip Cxd2545q. 512d26e

Three screws remove the mechanism. You’ll have to remove the drawer front first but supporting the tray and pushing the plastic fascia up and forwards, which will be a challenge if the tray belt has failed completely. If that has happened slide a screwdriver in front of the clamp and manipulate the large gear to drop the mechanism down and release the tray, at which point you can pull it out to remove the fascia piece.

Mechanism Without Tray Close

The mechanism then lifts out, and the large ribbon and tray motor cables are disconnected. If you can’t get the tray open, you could remove the front at the same time by removing four screws beneath the chassis (three in the feet, one in the middle). You’ll then be able to get to the gear beneath the mechanism to release the tray.

Flip the mechanism over and on the underside of the clamp assembly there are two clips on each side, roughly 60 mm apart. Squeeze them in and, while flipping the mechanism the right way up, remove the clamp. If you’re not careful the tray will fall off and so too will the gears.

There are three gears. The mechanism operation is quite simple. The motor drives the pulley via the belt, which in turn (via the small toothed gear on its top) drives the secondary gear at the rear of the assembly, which in turn drives the primary uppermost gear at the front. As the mechanism rotates, the gears operate in a cam motion against the teeth on the underside of the tray, lifting the mechanism up to meet the CD and holding the tray in place when it’s in the fully closed position. Note the orientation of the gears. Most are obvious, but it’s important the largest gear be oriented with its smaller section facing up.

Lift the gears off and optionally clean them with IPA. Likewise the pulley, and the pulley of the motor. You can optionally add a drop of oil into the tray, spindle and traverse motors at this point, and clean the laser if you feel confident in doing so. A spray of contact cleaner into the tray limit switch located next to the gear assembly doesn’t hurt either.

To reassemble, grease the three gear shafts lightly with silicone grease. Locate the pulley on the smaller shaft to the right and install the belt. Install the second gear to the small shaft closest to the laser mechanism, and then fit the larger gear. To set the timing, ensure the gear assembly is rotated to lift the CD mechanism to its uppermost position, and lay the tray on top with the toothed section on its underside meshed with the smaller section of the largest of the three gears.

Gear Under Tray Angle

The tray should seat correctly on its rails and the gear should prevent you pulling the tray forwards. Then reinstall the clamp to hold the mechanism together by aligning the clips with the guides and pushing down. The clamp only goes 1 way, made obvious by the magnetic clamping surface that sits over the CD spindle. You can add a film of silicone grease to the toothed section of the tray which will distribute it to the right gears without getting it all over the belt.

The rest of the circuitry is contained on the front board including the DAC, microcontroller, control electronics, display and output stage. I took the opportunity to remove this board, clean the display with IPA, and clean the headphone volume control pot with contact cleaner.

Overall Display Board

The CD servo board is on the bottom of the transport mechanism.

Sony Turned On

The CDP-361 sounds great and has a smooth, quiet transport. Track access times are unusually fast, and the extensive player controls on the front panel are a useful addition. It reads CD-Rs without complaint, and has no trouble playing scratched discs or discs suffering so-called ‘cd rot’ where the disc layers begin to fail. These are go for next to nothing on the second-hand market, they’re easy to service and there’s very little in them to go wrong. If you’re after a simple but high-quality and fully functional CD player, or a CD transport to feed discs to your DAC, the CDP-361 and its ilk should make your shortlist.

By Ashley

I founded Audio Appraisal a few years ago and continue to regularly update it with fresh content. An avid vinyl collector and coffee addict, I can often be found at a workbench tinkering with a faulty electronic device, tweaking a turntable to extract the last bit of detail from those tiny grooves in the plastic stuff, or relaxing in front of the hi-fi with a good album. A musician, occasional producer and sound engineer, other hobbies include software programming, web development, long walks and occasional DIY. Follow @ashleycox2

2 comments

  1. Another great repair and review Ashley. I’ll admit to being a bit ‘sniffy’ about such Japanese products through the ’90s. I was too persuaded by the UK HiFi press of the time who I now know simply found ways to downplay the performance of rivals to the companies who were paying for their advertising space on a big scale. Thank goodness that kind of nonsense is a thing of the past… (Joke)..
    Another solid CD player saved from landfill and can now give another couple of decades service!

    1. Cheers Simon. Just think where hi-fi would be today if the powers that be in the industry weren’t even more corrupt than the current crop of top-tier politicians…

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