This is either because it doesn't have certain euphonic distortions that create the sensation of energy, which is presumably a result of the characteristics of regular power supplies and output devices combined, or because it is intrinsically less muscular and less able to drive real-world speaker loads.

Digital amps of yore have suffered from a far higher sensitivity to the load they are driving than their analogue counterparts, which can result in a sound that seems to lack dynamics. Given that early stumble when fighting above its weight with the B&W, we lined up a variety of different speakers to see how well this aeronautical lawn-breaker coped.

In the main, it handled things very well. The Mole was unfazed by Acoustic Energy's AE1, a compact, metal-driver speaker that's designed to take a lot of power. The amp extracted a solid and tight bass allied to a super-detailed midband and a well extended and remarkably clean top end, one which revelled in finer, high-resolution recordings such as David Wilczewski's Room in the Clouds SACD.

Decent tonal variety

Similarly, the more analytical qualities of ATC's SCM19 standmount did little to undermine the Mole's case. Here, the amp allowed the speaker to reveal decent tonal variety from a male choir and a thoroughly engaging sense of timing. It also did a good job of distracting from the analysis and letting us hear the music.

Even the aforementioned 802D, while being too much of a handful for the amp to sound like it was in full control, illustrated how the quality of high-frequency resolve provides definition right across the audio band. The bass got a little boomy and lacked the conviction and gravitas that more powerful sounding amplifiers can extract from this speaker, yet the Mole did show the shape of higher bass notes well and managed to provide plenty of timing clues.

But of all the speakers tested, the Living Voice OBX-R speaker proved to be a very sweet match. The smoothness of its treble fused perfectly with the Mole's crisp top end, delivering a result with real sonic integrity, transparency and precision.

The Flying Mole design reveals what can be achieved with digital amp technology if you leave out the bells and whistles and focus on the essence. This is a remarkably refined performer, even in the face of some seriously good amplifiers in and around the same price.

The only real limitation is in the dynamic range, and even here this is a relatively mild shortcoming. This is not an amplifier that plays loud, but neither does it 'sound' loud at any given volume level. Normally, perceptibly loud amplification suggests distortion, but the CA-S10 understates the sound more than usual.

Other low-distortion amps seem louder because they pull out dynamics significantly better, which suggests greater sensitivity to level variations. Such designs are rare, but not impossible to find at the Mole's price.

So it's a matter of picking your compromise - there's usually an alternative that does something a little better. But here it's pretty fundamental: do you want a refined and incredibly clean sound that demands a smooth, high-quality source, or do you want a ballsy sound with grunt that is better suited to rocking out?

If you think that the former could be for you, then this small but beautifully formed amp is a hard act to beat. So long as you don't want the bells and whistles, of course. Jason Kennedy