There's a thin and often blurred line between a makeover and a redesign.

We're all painfully used to so-called 'revolutionary' new products that turn out to be last year's gear in this year's fashions. In that light, we can't help but applaud ATC and its SiA 2-150 amplifier.

Sturdy design

ATC – Gloucestershire's finest maker of loudspeakers, amplifiers and the combination of the two: active loudspeakers – has radically redesigned the look of its cult integrated amplifier, but there's no hint of a 'Mk ii', a 'Special edition' or a 'Limited'. There's not even a change to the product name; what used to be called the SiA 2-150 amplifier is still called the SiA 2-150 amplifier.

The reason for this is simple; what's inside this box is not so different to what was in the previous version. There have been changes to the PCB layouts and extra functions have been added, but ATc has stuck with what it considers to be a pretty solid design.

This means a wide bandwidth, low distortion, low noise floor and high output power design... and all of these features were already readily available from the last model. So perhaps this is the ultimate expression of the 'if it ain't broke, don't fix it' ethos in today's hi-fi industry.

Lower price

We originally reviewed the last SiA 2-150 in June 2002 and it was not a brand new product then, what's more it cost £2,375.

The fact that the latest version costs more than a hundred quid less than it did six years ago is apparently because ATC has refined its production process to be more efficient; there's also an economy of scale, as ATC upped the numbers it builds to accommodate demand from new markets.

Nevertheless, for a company to be able to add a better looking bit of casework and extra socketry while reducing the price in both real and actual terms is hugely impressive.

Beautifully made

The snappy product name remains merely a stark description of its role: SiA stands for stereo integrated amplifier, 2 for the amount of channels and 150 indicates the power in watts that it's specified to deliver into an eight ohm load.

Its beautifully machined aluminium front panel is 12mm thick and offers the minimum of controls, one large knob adjusts volume while the other is used to click through the four inputs indicated by green lights in the central bar. The two smaller buttons are for standby and monitor, the latter accessing whatever is connected to the tape input, who knows it might even be a tape recorder.

There is also a slightly lightweight remote handset which can be used to do all of these things as well as mute the output. outputs consist of preamp (variable), subwoofer (fixed) and headphone socket.

The good news here is the socket is the traditional 6mm jack (instead of the all-too-common 2.5mm mini jack nicked from portable audio); the bad news is that it's placed on the rear panel, which is inconvenient but does keep the front looking good.

Focus on power

ATC, being a company with strong ties to the studio world, believes in power being a necessity for accurate music reproduction.

This is why this amplifier has a massive power supply that delivers a class A/B output of 150 watts. The first two thirds of which are said to be in class A.

This puts it in a pretty select group for its price; there are only two other integrated amplifiers that compete on watts per quid in our listings and both of those come from large companies.