Pre/Power Amplifiers

‘Business as usual’ marks life at Audio Research under Quadrivio, its new, Italian owners. The American-as-root-beer virtues that exemplify the products remain; banish any notions that we’ll see ARC amps made with staves of curvy walnut. The new 120W/ch VS115 is pure Yankee ARC all the way, though one now needs to turn to Russia for 6550s.
   Advancing from the VS110 by adding balanced inputs, the VS115 retains the layout of its predecessor: open architecture and an anodized top plate with every aperture clearly labelled for each of the eight matched 6550 output tubes and the quartet of 6H30 gain and cathode follower valves. Optimal ventilation is a given, the structure preventing all but the most majestically stupid of users from putting anything on top of it.
   As is ARC practise, the VS115 benefits from the development of the Reference models, in particular the REF110’s FET input stage design. It means that we now have a medium-size stereo amp from Audio Research with both balanced and single-ended operation in a true differential topology. The balanced-vs-single-ended debate will never end, but I am one who categorically prefers the former. It’s no coincidence that my favourite preamps, eg McIntosh’s C2200, work best in that mode.
   Changes over the VS110 include much wider power bandwidth (100kHz in contrast to 40kHz) and output up by 20W/ch on its predecessor, though still residing in what is arguably the ‘middle power’ category in today’s market. Used with Sonus faber’s (now Audio Research’s sister brand) Cremona Auditor Elipsa loudspeakers, power was not an issue.
   Bias test points for each valve are located on the rear panel, with adjustment through apertures near each valve base. The back also contains 12V triggers for system switch-on, binding posts for 4 and 8ohm speaker loads, a socket for the heavier blade-style detachable mains cable, and the input sockets, with small jumpers to prevent access to the XLRs if you use really must use this in single-ended mode.
   Audio Research promises ‘more speed, top-end air, improved mid-band resolution and more articulate, impactful bass’ over the VS110. ‘Textures and timbres are finely rendered and silky-smooth, with the grainless resolution that only our reference series amps have previously been capable of.’ All of which had me anticipating a baby version of the REF110, one of my all-time favourite ARC amps. Although, if I had a Lotto win, I’d spring for a REF210 and hide the display...

GRIP AND FLUIDITY
Once I’d manoeuvred the rear-biased 28.2kg, 445x201x483mm (whd) bulk onto a GM Accessori table, I wired it with Yter cables, to the rest of the system: C2200, SME 30/Series V turntable with Transfiguration Orpheus MC, Audio Research’s PH5 phono stage. Fresh from sessions with the Feickert turntable [see p56], I continued with Classic Records’ live Dylan, mono LPs from Connie Francis and Louis Prima, plus my treasured 7in copy of Mr Big’s ‘To Be With You’. New to the pile were LPs of Mudcrutch – Tom Petty’s return to a pre-Heartbreakers band – and Keb’ Mo’s eponymous debut.
   There’s much to be said for avoiding the excess of 200W-plus behemoths, despite exhortations that there’s no such thing as too much power: cost, bulk, green issues. Some years ago, one of audio’s gurus noted that the sweetest-sounding amps in his experience were all 60-watters; my own litany of favourites, too, consists entirely of what would be deemed power-shy by today’s standards. The VS115 seems, then, to be an ideal update for that dictum. After all, we’re only talking another 3dB.
   If power is one of your obsessions, let me assure you that, in my ‘typical’ 12x18ft room, the VS115 delivered more than enough level from the baby Elipsas, the Guarneris, LS3/5As, PMC’s DB1+ and the hungrier-than-you-think Tannoy Autograph Mini. In every instance, whatever bass the speaker could offer, was exploited to the fullest; consistent from speaker to speaker were grip and fluidity without any traces of artificial snap or hardness, while the matching with the Mk I Guarneris was on a par with the best I’d ever heard: mid-to-late-1990s Krells. If there’s anything lacking, it’s the sort of weight that the REF610T brings to the party. But then, I’m not a bass addict.
   All of the above speakers excel in soundstage recreation, so it was joyous to find that the VS115 is an absolute champion of three-dimensionality, especially stage depth. Width was OK, nowhere near the best I’ve heard – those absurdly huge Musical Fidelity kilowatters – but it extended beyond the speakers’ edges every time. The depth appeared most vividly with live Dylan, the amp seeming to grace the space with another few metres of depth.

NOT FOR BEGINNERS
What most revealed the worth of the VS115 relative to my particular set of quirky needs were specific instruments and voices, such as the bottleneck guitar-work of Keb’ Mo’ and the slightly nasal yet thoroughly distinctive vocal delivery of Tom Petty. As a showcase for his tremulous voice, the VS115 delivered every nuance, useful for a side-by-side contrast with Roger McGuinn – in case you think the two are interchangeable. And on occasion, they are.
   Better still was the metallic twang of Keb’ Mo’s National Steel. It shimmers through the VS115, entering the room with the sashay of a 1940s lounge lizard – this amp could have been custom-made for Slim Gaillard. Underscoring its solidity, a true foundation: the opening notes to ‘Am I Wrong’, with that not-too-dry kick drum, will excite the hairs on your neck.
   Mono: dead centre. Female vocals: liquid. Prima’s brass: punch with perfect transients. Overall texture: silky rather than squeaky-clean. In other words, valves for the aficionado. Not the neophyte.

VERDICT
Because the VS115 competes with stunners from McIntosh, Quad, Air-Tight and so many others, ‘choosing’ equals ‘torment’. But Audio Research engenders brand loyalty. With the VS115, its supporters will not be disappointed: here is classic ARC behaviour in every sense. Solid, fast and robust, yet transparent and delicate: one could want for nothing more.

Originally published in the October 2008 issue.