On the surface, it's just another set of modifications, right? Another way to sell CD-63s, eh? I suppose that a cynic could look at it that way, but - after hearing the 'K.I. Signature' - the cynic would have to recant. Moreover, the lateral thinker rather than the cynic would recognise in the Marantz CD-63II K.I. Signature CD player (to give this machine its full name) a set of opportunities rare in audio which can help to convey vividly the meaning of the term 'upgrade'. That's because the K.I. Signature, the third variant, makes the CD-63 uniquely positioned to do so.

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Traditionally, models dubbed 'Signature' tend to be hot-rodded versions of products which are upmarket from the outset. Ones which come to mind include a couple of Acoustic Energy speakers, some Grado cartridges of yore and the like. But, for the most part, hi-fi manufacturers do not tend to run numerous concurrent versions; it's confusing and messy. So, invariably, when a product undergoes extensive modification, it becomes a replacement for the model on which it was based. With the latest version of the CD-63, however, the consumer can - like the car buyer - choose according to price and desire within a same model 'family'. And Marantz has priced them far enough apart to ensure that they're not mutually exclusive.

Think about it. If you want a car, any car, the odds are that it's available in myriad forms, to suit both your budget and your expectations according to social and/or driving needs. A Peugeot 106? 1.1 or 1.4 litre engines, diesel, three- or five-door, sporty or plain. A Ford Fiesta? You'd need a whole magazine to list the options. In hi-fi, it's take it or leave it. But Marantz has given us the plain vanilla CD-63 (now Mk II, that is), then the CD-63SE with uprated chassis and improved components, and now the Ken Ishiwata Signature version. As all three are currently available, it affords the retailer another unique opportunities beyond being able to offer three variants of the same model to the customer: it enables the shop to perform vivid A/B/C demonstrations which are beyond reproach.

Imagine, if you will, going into a shop to buy a CD player for £500 or under, and - instead of being offered three wildly different, mutually exclusive models from three non-sympathetic manufacturers - the retailer shows you a trio of models identical but for details which enhance the performance. At extra cost, of course. Prices? The basic CD-63 can be found for around £270, the '63SE for £350. The new K.I. Signature? £500. A nice point spread, so to speak, guaranteed to space the models sufficiently to avoid confusion. And provided that the retailer has three copies of the same CD, you can feed all three versions of the Marantz into the same line-level preamp or integrated and switch from one to the other for perfect comparisons. How so? Since they all work from the same remote control, setting up synchronised playback is a breeze.

Fundamentally, a CD-63 is a slim-line budget player jam-packed with every facility expected of a CD player, plus remote volume control (great if you have a pre-amp or integrated lacking said convenience item). It uses Philips' CDM12.3 three-beam laser assembly with digital servo-drive (DSD), a single-bit converter and Hyper Dynamic Amp Modules (HDAM) to reduce noise in the analogue output section. The latter devices are probably the secret to the CD-63's supremacy in the entry-level arena. What Ken Ishiwata has added to the SE's recipe to justify the Signature tag are a new, over-sized ultra-low-impedance toroidal transformer, a completely copper-plated anti-vibration chassisand improved copper versions of Marantz's HDAMs. To give you some idea of what the K.I. Signature HDAMs do, they improve on the 80V m/sec slew rate of cheap'n'nasty op amps to typically 15V m/sec.

Only two external details identify the K.I. Signature: the flashy name plate on the front and large copper-coloured areas visible underneath. It's this which is particularly Ishiwata-esque, harking back to the high-end Marantz CD players with which he's been involved, including the CD-12/DA-12 which started the ball rolling. The overkill power supply, matched components and greater resistance to vibration are also Ishiwata trademarks, so the K.I. Signature labelling is no mere conceit. (It should also be known that, belatedly, Marantz Europe has recognised Ken's deserved pan-European celebrity status and its market value. And putting a designer's name on a product must be a first of some sort for a Japanese electronics firm, even one that's Dutch-owned.)

Given that I keep a '63SE as my budget reference and a bunch of duplicated CD titles for such comparisons, I was able to A/B myself into oblivion. Alas, the results were more difficult to confirm because the gains were of the most subtle sort, and certainly not as gross as the difference between a standard '63 and the 'SE. It's a situation which, ironically, provides us with another unique opportunity: an audition consisting of the standard CD-63II versus CD-63SE versus K.I. Signature provides painful proof of 'The Law of Diminishing Returns'.