Pre/Power Amplifiers

Very low and very high power outputs tend to under-read here, so a 0.75W/8ohm output appears as 0.075W on the REF80S's 'Pentode' scale while 75W/8ohm, just prior to clipping, registers at the tick midway between 7.5-75W. However, a mid-power 7.5W/8ohm – not an unlikely output in common usage – finds the needle flickering near enough bang-on the mark.

Music On Tap
There are certainly no 'bangs' when you fire-up the REF80S, its output muted for a couple of minutes as the PSU and KT150s cycle up and back down again to stabilise the tubes' temperature and biasing. Connection to the rear 16, 8 and 4ohm speaker taps is not necessarily so straightforward – in Triode mode you'll achieve the best results with 4ohm nominal speakers connected to the 4ohm tap (circa 40W), but the same is not true in UL mode. Here the KT150's screen grids are connected to an additional transformer winding – the 'feedback' squeezing down tube distortion – this configuration causing the REF80S to deliver more power into tougher 4ohm loads from its 8ohm output (~80W) than via its 4ohm tap (~45W).

I reported the same 'feature' in our VT80 review and here, as there, I heard my 'reference' B&W 800 D3s [HFN Oct '16] singing most confidently via the REF80S's 8ohm terminals. I'd dearly love to have experienced the REF80S with the high impedance/high sensitivity DeVore Fidelity O/96s [HFN Apr '21] as these would be one of the very few speakers to make good use of ARC's unusual (these days) 16ohm option. Sadly, the Audio Research REF80S and DeVore O/96s passed in and out of my listening room like ships in the night...

Nevertheless the REF80S commands sufficient presence, and down-to-earth 'grunt', to marshal tremendous sonic forces – necessary in realising the likes of Wagner's Ring Cycle [Duisburger Phil/Jonathan Darlington; Acousence ACO21309, 192kHz/24-bit]. This it does with not a little substance and style, the panoramic richness of the 105 players – including guests! – revealed across a gloriously wide and deep soundscape.

The instruments, from violins to oboes to tympani and harps are all sharply drawn but their union is a richly coloured tapestry, not a contrasty black-and-white sketch. The chimes and other percussion that mark the Nibelungs' 'Forging' sounded spectacularly vivid here, the hollow metallic ringing bringing a very realistic sense of height to this orchestral drama. If you fancy being swept away by music of such scale, then the REF80S makes for a very secure lifeboat.

It does intimacy too. Chip Taylor and Carrie Rodriguez's 'Sweet Tequila Blues' [Let's Leave This Town; Train Wreck Records TW019] is about as undemanding but sensitively-played a C&W set as will caress your ears, Chip's world-weary lament juxtaposed by the punchier quality of his more youthful fiddler and vocalist companion. With the REF80S in tow you are not so much invited as compelled to drum your fingers and tap your feet as you are wrapped in the close, but never cloying, acoustic of this very honest, stripped-back recording.

Ready To Rock
But can the REF80S rock? You bet! I could feel the raw electricity generated by Lifeson's opening riff to the 96kHz remix of Rush's one-time chart hit 'The Spirit Of Radio' [Permanent Waves 40th Anniversary; Mercury Records]. Peart's drums, and the backing sequencer, possessed all the impact and energy I'd expect to hear from the big Constellation amps [HFN Oct '19] that ordinarily put the hammer down on my 800 D3s. Like these monoblocks, the REF80S has genuine 'slam', delivering bass with richness, texture and speed – there's none of the laziness or overhang you might hear from a more 'traditional' tube amp.

Tubes Or Transistors?
Time passes, to be sure, but the security and 'positivity' of the REF80S's presentation reminded me of listening to the fabulously eccentric KR Audio Kronzilla DX [HFN Sep '15] with late-lamented colleague and contributor John Bamford. KR's custom T-1610 direct-heated double-triodes are an entirely different kettle of filaments, but the REF80S shares with them a solidity of sound, a definition and precision that's as close to 'solid-state' as any tube amp would care to attempt. This is 'tube sound' curated for 21st century listening.

Hi-Fi News Verdict
If Audio Research's first act of freedom was to embrace the 'everyday' audiophile then the forthcoming I-series looks to be just the ticket, just as this REF80S is surely the most accessible and compelling gateway to its top-tier Reference range yet offered. It's hardly beer-budget stuff but the fiscal strain will likely prove secondary to the emotional wrench if you hear this amp in full flight but then must walk away.