One measure of truly excellent hi-fi components is that they will sound exciting and stimulating regardless of the sort of music you play through them. They won't restrict you to listening to those vacant, over-polished demo 'favourites' we've come to loathe over the years.

Naim's new entry-level pre/power combination - the NAC 122x preamplifier and the NAP 150x power amplifier - falls squarely into this 'exciting and stimulating' camp. In fact, when first listening to the duo, it's hard to believe that they are entry-level offerings: they seem far more composed and effortlessly informative than any 'starter' combination has any right to do.

The £750 NAC 122x replaces the NAC 112x in Naim Audio's preamp hierarchy, and draws on the heritage of the more upmarket and expensive NAC 202. In terms of improvements over the model it replaces, the new design uses a hard-wired, motorised, Alps volume control for better performance, lower noise in use and an improved feel over the resistor ladder control of the NAC 112x.

Its six inputs are relay-switched rather than being multiplexed, as were those of its predecessor, which, again, is said to enhance its performance.

Furthermore, great care has been taken to make the casework and PCB as low resonance as possible and to isolate the PCB from the environment and any deleterious vibrations present therein. This means that you'll encounter a little play when plugging in connections but this is intended to be there and is nothing to be concerned about.

The £825 NAP 150x represents Naim's first step on the power amp ladder and its design also owes much to more upmarket Naim models; in this case, the flagship NAP 500. It features many improvements over the original NAP 150, including a hefty toroidal transformer for improved regulation, with discrete windings for each audio channel. There's also an enhanced power supply for the preamplifier.

As is common with most Naim preamps, the NAC 122x can be upgraded - or, perhaps more accurately, users can explore the full potential of what it has to offer - by using an external power supply unit. This is an approach to design that seems outwardly unusual, but one that makes perfect sense when you hear the improvements that it can bring.