The Plinius 9100 is an integrated amplifier with a moderate 120-watt output rating, but what you probably don't know is that it is also the entry-level model in an extensive range of two-channel and multichannel power amplifiers, integrateds and preamps, some with switchable class A and class AB operation.

In fact, the circuit of the 9100 is a scaled down version of the one in the company's high-end Odeon power amplifier. There are also other products, notably an appropriately exotic CD player called the CD-101.

Standard fare

On paper, at least, the 9100 follows a path familiar to other high-end producers. There are few frills, although it is equipped with four line inputs and two tape circuits (which can double as line inputs if needed), with a preamp output and bi-wirable sets of solid 4mm binding posts.

Mains power is supplied to an IEC input and an earth lift switch is available on the back panel which may well be appreciated by adding a phono step up, but this was not required for this test. The fuses are also externally accessible, along with a mains on/off rocker switch.

The J-FET inputs all offer a 47kOhm input impedance, which will make system matching easier than the usual amplifier with lower input impedance values. The inputs are tailored to be -3dB at 5hz and 70khz, so the same comment applies here too.

Power output is 120 watts into 8 ohms, 20hz – 20khz at <0.2 per cent THD. There are no traps here for the unwary. Our test sample came without a remote control, but we understand that a large brick-like remote is available to control the source input selection and the volume level.

Solid form

Front panel controls are limited to volume, plus record and source selectors with clear markings in each case and internal LED displays.

The most unusual feature of the 9100 is the rounded exterior front panel, which means no sharp edges and an aesthetic character that mirrors the Classé range, albeit in a more elegant, slimline form. It's all beautifully executed from the front, but if any criticism is to be levelled then it's in the use of protruding screws on the top, which are all too clearly visible. Full marks to the rear side extensions, which include small grab handles.

There is little else you need to know. The amplifier doesn't run excessively hot and it's quiet (hum and noise free) under normal use, that is with the volume set high and no input. Just be sure to warm the amplifier for about an hour at the start of a listening session.

For those with greater ambitions than the 9100 will satisfy, take a look at the visually almost identical 9200, which starts out with the same basic configuration, but which adds a balanced input, a processor loop so that it can cooperate with a multichannel processor or amplifier's volume control and a phono input intended for MM and MC cartridges. Power output is also higher, at a rated 200 watts per channel.

Valve sound

Amplifiers come in various guises. Some are transparently neutral, or strive to be. Others have a more deliberate character and this is true of the Plinius 9100.

There is something of a valve-like character to the 9100. OK, perhaps it would be an oversimplification to say that this amplifier has the qualities of a valve amplifier, as there are very few worthwhile designs of that type anywhere near this price and none at all in this price category with the real world power output that this amplifier brings to bear. But, it is hard to gainsay the idea that there really is more than a hint of valves here.

The 9100 is at its best in the middle registers. On a bad day, the Plinius can sound a little bloated at the low frequency extreme, though you can counter this with careful positioning and speaker cables that don't exaggerate the problem – Nordost Valhalla fits the bill extremely well here, not because it has lean balance, though this is a common accusation, but because it is so well-controlled throughout the audio band.

The treble extreme, by contrast, is rather sweet (valve-like) and finely detailed without being particularly demonstrative. If anything, the sound is a little understated in this region. Where the Plinius excels, as noted above, is in the middle registers. This is a sophisticated, expressive sounding amplifier, which invests music with a feeling of solidity and architecture and this definitely is a valve-like attribute, though it is achieved here with little or none of the traditional losses of dynamics and drive.

If anything, it is just the opposite. It's a very well-controlled, but unusually muscular amplifier. Rock material has real strength and solidity: Dire Straits' Calling Elvis, for example, comes up smelling of roses, with a real underpinning pulse, where in some systems it can sound a little flabby.

And ditto Ry Cooder's wonderfully quirky 3 cool cats lyrics from Chavez Ravine. Similarly, Diana Krall's classic Boulevard of Broken Dreams and Marianne Faithful's whisky-flavoured Alabama Song from 20th Century Blues both come across with a touch of electricity, along with the indefinable magic that through other amplifiers can fade with repeated listening. This remains the case, even with the volume control turned to levels where other similarly rated amplifiers are beginning to sound ill-at-ease.

There is no reason to think that power output is necessarily greater than other similarly rated amplifiers, but the 9100's 120 watts is arguably more useable than most, no matter (within reason) the starting volume level setting.

There were similar results with other music genres, too, not least classical, which is where we tend to start in some reviews. It does a great job with vocal material of all kinds, from Strauss Four Last Songs to the equally sprightly Cecila Bartoli singing Mozart's Im Uomini, In Solidati from Cosi fan Tutte (you'll recognise it when you hear it).

We were equally impressed with instrumental and full-blooded orchestral material, or nearly as impressed. There is something about the Plinius that empathises particularly well with the human voice.

There are any number of good amplifiers in the same price territory as this one and, to an extent, choosing from among them is a matter of taste as much as anything more objective. But we really like the 9100, which is supremely well-balanced and whose midband, in particular, sings like a thoroughbred.

We are now more than a little curious to find out what the senior version, the 9200, can bring to the party. But as it stands, the 9100 is a fine, expressive amplifier with a more than a useful ability to play loud and one which works unusually well with the human voice.