Integrated Amplifiers

Set-up is as straightforward as it gets, although be aware this warm-running amplifier needs sufficient ventilation – Pass Labs recommends a minimum of 6in clearance. There's a remote control as minimalist at the amp itself, with small-scale buttons lost amid a desert of brushed metal. Note this is the same handset used across the company's better-specified designs, so it offers controls for features – including balance and pass through – that are redundant here. But you can use the remote to dim the LED display if desired.

Velvet Underground
Pass Labs' claim that this amp 'breathes new life into the music' is, of course, what hi-fi brands say about even the most prosaic of products, but here it really doesn't feel like hyperbole. The INT-25 is an effortless, unfatiguing listen, but there's no feeling of details being glossed over or thrown away in favour of reassuring warmth. The sound is succinct and clean, resolving musical minutiae with finesse. Just as importantly, this notionally 25W amp behaves like something beefier, powering through percussion and bouncing along with the most robust of basslines. There's a rich, velvet quality to its low-end that's as appetising as its upper-band acrobatics and tonal nuance. In short, it's rather special.

Take Moby's 'God Moving Over The Face Of The Waters' [Everything Is Wrong; Tidal MQA] – a sweeping synthetic piece used to close Michael Mann's epic crime drama Heat. With the INT-25 in charge, this track swelled from my three-way floorstanders, creating a soundstage that combined light and dark as sweet-sounding strings faced off against deep, surging bass. There's nothing particularly inventive about Moby's mix, yet through this amp it still managed to sound layered and involving.

Deft At Dynamics
This was just an amuse-bouche. A greater appreciation of the amp's musical quality and soundstaging came from Johannes Pramsohler and Ensemble Diderot's Audax recording of Montanari Violin Concertos [ADX13704; 96kHz/24-bit FLAC]. Right from the start of No 6(i) the INT-25 exhibited a seductive liveliness, which helped emphasise the piece's overt jollity and had violin and harpsichord notes dancing from my speakers. I wouldn't really describe it as an up-and-at-'em performance, for this integrated is too even-handed to ever be considered rowdy. Yet nor is it frustratingly polite. The dynamic peaks and troughs of Pramsohler's playing demand an amp with a deft touch and transient ability – and, via the INT-25, that's what they got.

Natural Groove
I like to think that really great hi-fi experiences have a 'wow' moment. My 'wow' moment with Pass Labs' integrated came from a replay of 'Albert's Shuffle', the 1968 blues instrumental from Al Kooper and Mike Bloomfield [Tidal 44.1kHz/16-bit]. This superb recording dovetailed with the INT-25's abundant expression and sheer believability, leaving me imagining myself sat in a smoke-filled backroom bar, tapping my foot while watching virtuosos at work.

The track starts with a walking blues bassline, brushed hi-hats and a vibrato-filled guitar solo. The tone of the latter was startling, Kooper's picked notes given a piercing leading edge followed by textured highs. Then came the wider instrumentation, including Hammond organ, ondioline, horn and tenor sax. Each had its own distinct sound, was afforded its own space and was staged with precision amid a pleasingly deep soundstage. Best of all it came across as a gang of musicians having a thoroughly good time, locked into a natural groove.

The scale this 'smaller' Pass Labs amp can engineer from a range of recordings is exceptional. Pantera's 'Domination' [Cowboys From Hell; Atco Records 7567-91372-2] gained a stature that its reverb-heavy mix had always suggested, yet I'd never previously heard or fully enjoyed. The pounding kick drums that signal its coda hit hard and sounded huge. Heading further down the dark and dirty rabbit hole, I ended up at Dillinja's drum 'n' bass track 'Hard Noize' [Tidal 44.1kHz/16-bit] where the INT-25 again enjoyed the challenge. It gripped my speakers' woofers with authority, finding the sub-bass beneath the bass.

Regards power, the INT-25 had the subjective grunt to never sound like it was straining with my floorstanders. Swapping them for some Q Acoustics standmounts, and ignoring the price difference between amp and speakers, it made the compact cabinets sound substantially bigger than they are. The amp's character – energetic but not aggressive, musical and deliciously detailed – still shone through, so it's hard to imagine it not forming a formidable partnership with anything but the most needy of loudspeakers.

Hi-Fi News Verdict
If your test for an integrated amp is one that sounds extremely musical without lacking muscle, then the INT-25 passes – if you'll excuse the pun – with flying colours. That a product at this price should ooze no-nonsense build quality, if not style, is almost a given. But sublime sound? Here, yes. So Pass Labs' spec. may hint at a back-to-basics approach, but when the basics are this good, who needs the extra frills?