In the escalating product race between Denon and Marantz, both companies have introduced a range of high-grade disc players and amplifiers that have helped to push the boundaries of what's commonly referred to as 'state-of-the-art' in the world of hi-fi.

The Marantz SA-7S1 is an excellent example of this. It's a stereo-only model and is Marantz' best CD/SACD player to date, from a range so far known as the Legendary Series.

It's not a rehash of anything that came before either, and that includes its spiritual predecessor, the mighty SA1, which sold for around the same price, until it was discontinued in 2002, leaving a top-end gap.

The external casework and general presentation owes much to the more recent CD-7, but with subtle changes. It has many of the same trademark features, including a copper-plated chassis and an unusually solid, low-resonance dual-layer base.

The mechanism is a new in-house design based on a disc tray fabricated from 10mm thick solid aluminium to reduce resonant behaviour and to inhibit internal noise radiation. Where other players use opto-couplers to provide ground plane separation between different functional areas of the circuit, the SA-7S1 uses digital isolators using Giant Magneto Resistive materials from Swiss company IsoLoop.

A key piece of the internal digital clockwork is the PEC777f2, which performs multiple roles, acting as a digital filter, DC filter, noise shaper and eight times oversampler.

Features include selectable absolute phase inversion performed in the digital domain, which should (and to our ears, does) mean no unwanted side effects, and an input for an external high-precision clock.

The latter parallels a similar facility found on some other players, from Teac Esoteric and dCS, for example, and makes the SA-7S1 capable of locking onto clock signals of 44.1, 88.2 and 176.4kHz presented to a rear panel BNC.

There is no Marantz-branded clock available, however, even in Japan, and we didn't have any third-party clock to try. Our prior experience with such devices is that some players - for example Esoteric - tend to benefit, but in other cases the result is merely a difference, which is difficult to describe as better or worse.

The obvious quid pro quo is the additional cost of the clock, which is likely to be of the same order as the player itself.

The power supply is described as having a choke input. This is nothing to do with choke regulation, Musical Fidelity style, which some suggest make amplifiers sound as though their bass and treble run independently, like having two amplifiers in one box - an odd, and slightly disconcerting sensation.

We discovered during conversation with Ken that he has had a similar experience. The configuration used here is optimised for consistency across the frequency spectrum, and for overall dynamic range, which in his words is "difficult to do".

The display is said to be a low noise design, though it looks like a conventional enough fluorescent design. Standard optical and coaxial digital outputs are available from CD only, but they can be switched off when not required.

And like virtually all self-respecting high-end players these days, the analogue audio output is available in balanced and single-ended form. The SACD section delivers text readouts from text-enabled SA discs, but this sadly doesn't extend to CD Text, which would have been good. So would a smoother scrolling text display, but that's just being pedantic.