Pre/Power Amplifiers

The overall effect is rather intriguing then – it's almost a valve amp for someone who's not quite willing to go fully 'native'. Especially when running in ultralinear mode, it has a distinctly upfront sound that will be more familiar to solid-state fans than long-term users of Quad IIs. Indeed, cue up Steely Dan's 'Home At Last' [Aja; MCA Records 088 112 056-2] for example, and this normally fairly smooth and silky '70s rock track actually becomes rather forward and feisty. That's not to say it sounded harsh, but neither were Donald Fagen's distinctive vocals shy and retiring. This complemented the well-lit treble, as cymbals came over with bite. Bass was punchy and thumpy, the power amplifier delivering a big thwack into my loudspeakers, as if to make a point.

The EVO 400 pre/power combination sounded unexpectedly barrel-chested for things that glow in the dark, and anyone walking into the room without seeing the electronics being used would most likely laugh if you told them it wasn't solid-state. This combo has real guts and oomph then, with just a slight padding out of the upper bass to signal its valve origins.

Whistle-Clean
When I switched to triode mode, the same Steely Dan song was instantly transformed. No longer did this combo sound so physical, as there was a subtle diminution of bass power and a slight flattening of treble. Yet the midband came into its own, the textures of the many different instruments now distinct, vibrant, less generic. I began to hear real tonal colour, with the saxophones presenting themselves in a softer and more subtle way, their rawness unabrasive but better resolved. I was also struck by the piano sound in triode mode, as it was deliciously rich and bristling with whistle-clean harmonics. By comparison, in ultralinear mode, this same instrument sounded more artificial and processed.

In practice the switchable ultralinear and triode modes completely define this amplifier for while it's a great feature to have, it's also quite distracting. During my listening, the more I got to know the amplifier, the less I fiddled with the remote, and indeed began to realise that my choice of programme material was beginning to make the decision for me. For example, when I cued up Nookie's 'Give A Little Love' [The Sound Of Music; RIVET CD 05] the jury wasn't out for long. This is no slinky Steely Dan jazz-funk, it's banging early '90s jungle/hardcore, bristling with scratchy 8-bit samples and a massive sub-bass.

Here triode mode sounded a touch too soft – it was clearly better in the midrange but all the action was with the sub-bass modulating up and down, and the frenetic hi-hats crashing away above it.

Ultralinear mode added a welcome bite that made the song sound wonderfully visceral. Even at seriously high listening levels, the EVO 400 power amplifier held on tight and showed few signs of its output transformers saturating. Indeed, I couldn't help thinking to myself, 'Gosh, all this power from pairs of EL34s!'.

Just to complicate things, the ultralinear/triode divide doesn't confine itself to power and tonal colour. The former is brighter and bassier, while the latter still delivers music in a more fluid, free-and-easy way. Even the frenetic Nookie track flowed a lot better in triode mode, so I loved the way the drum machine's rim-shots and snare loops were more easily distinguished.

This was even more obvious with pop music such as ABC's 'Date Stamp' [The Lexicon Of Love; Phonogram 32PD-90], which bounced along at a cracking pace. The song's subtle rhythmic nuances, such as the rhythm guitar work and phrasing of Martin Fry's vocals flowed better, and to great emotional effect.

Large 'N' Luxurious
This pre/power seems able to get into the song's groove right down to an almost granular level, as if to celebrate what was secreted inside this classic early '80s recording. By contrast, to these ears, many more expensive solid-state amplifiers sound far more matter-of-fact.

Finally, the sense of recorded space never failed to impress, whichever way one ran this pre/power combination. Good valve amps seem to have a special knack of making music seem larger than life, and this PrimaLuna duo was no exception. The haunting modern jazz of Herbie Hancock's 'I Have A Dream' [The Prisoner; Blue Note TOCJ-4321] had a luxuriously wide acoustic. This classic late '60s track is simple but effective, and the EVO 400 pre/power amps opened it right up.

The combo's confidence when driving even awkward loudspeakers meant it threw images far stage left and stage right, yet was subtle enough to hang things back nicely, especially in triode mode. The beautiful flute, trumpet and flugelhorn playing also charmed me, being locked confidently in space, panned hard to either side and dancing between the speakers.

At the same time, I was struck by the sheer absence of noise and hum when using this pair of amplifiers, which only further helped the sense of scale and three-dimensionality on offer. It was yet another reminder that this is a thoroughly modern valve pre/power design.

Hi-Fi News Verdict
The PrimaLuna EVO 400 pre/power gets embarrassingly close to the top tier for a fraction of the price of high-end equipment. Given a good source and loudspeakers, it's the impressive centrepiece of a serious hi-fi system – one with a charm that many rivals conspicuously lack. A great affordable audiophile valve amp combination then, built to a high standard and with masses of upgrade potential.