In common with most of the rest of the world, Marantz seems to be updating its ranges more rapidly these days than a few years ago, but certain aspects of the Marantz PM8003 integrated amplifier look familiar from mid-range Marantz models of yore.

The use of HDAM (Hyper Dynamic Amplifier Module – effectively an op-amp circuit, but built with discrete components and optimised for audio duty) circuits certainly comes under the heading of 'if it ain't broke, don't fix it' and we'd swear we've seen some corners from the rest of the circuit before too.

Power supply

In terms of new design, Marantz is keen to emphasise that there has been considerable influence from its upmarket amps, which act to some extent as technology proving grounds for more mass-market designs.

The power supply starts with a large toroidal transformer, which feeds a bridge rectifier made up of high-speed diodes mounted on the main heatsink.

A rectifier diode seems an awfully prosaic component to tweak, but regular ones have been shown to create high-frequency interference which, while not necessarily directly audible, seems to cause some mild degradation of fine detail in delicate audio signals.

High-speed ones reduce that and mounting them on a big heatsink is even more beneficial as it 'swallows up' most of the radiated field from the diodes.

Clearer bass

The next stage after diodes is smoothing capacitors and here again Marantz has done the listener proud with unusually generous provision.

This is another of amplifier design's near-intangible issues, but there is substantial accumulated evidence to support the argument that larger capacitors are very much a good thing, tending to give a fuller and also clearer bass.

As for the main circuitry, there is less evidence of tweaky construction here and indeed most of the passive components (resistors and capacitors) are thoroughly mundane types. They are assembled to a circuit board that in today's high-tech age looks frankly retro, with wire links and not a surface-mount component in sight.

Volume control

About the only real concession to modernity is a solid-state switch for input selection, a familiar part which we've found in the past to offer good performance: it also avoids a weakness of some such parts with regard to high input levels, which it accepts without complaint.

The volume control is the noted Alps 'blue velvet' type, a component not found in many mass-market products, motorised for remote control convenience. Although it has good sound quality credentials, we did find it a bit twitchy to use over some of its range.

Finally, there is a phono stage, suitable for moving magnet (high output) cartridges only. Assembled on its own circuit board as far as physically possible from the mains transformer, it is quite a deluxe-looking affair built from discrete transistors rather than the usual single op-amp afterthought.

Robust build

Physical build of the amp is good, with decent-quality connectors, nicely weighted switches and some very chunky output terminals, a little pretentiously finished in 'faux metal' – they're actually plastic on the outside.

From them issues a healthy output: Marantz's rating of 70 watts is conservative and we got more like 90 watts, with admirably low distortion and impressively flat frequency response from line and phono inputs alike.

Lacking detail

Having been used to high standards from Marantz amps over recent years, we were just very slightly underwhelmed by PM8003, which seems to lack some of the insight we've found in previous models.

The sound is large-bodied, tonally full and never less than pleasant, but it doesn't seem to have quite the level of detail that the PM7001Ki offered.